-
Cellular and Molecular Life Sciences :... Nov 2023During macroautophagy, the Atg8 protein is conjugated to phosphatidylethanolamine (PE) in autophagic membranes. In Apicomplexan parasites, two cysteine proteases, Atg4...
During macroautophagy, the Atg8 protein is conjugated to phosphatidylethanolamine (PE) in autophagic membranes. In Apicomplexan parasites, two cysteine proteases, Atg4 and ovarian tumor unit (Otu), have been identified to delipidate Atg8 to release this protein from membranes. Here, we investigated the role of cysteine proteases in Atg8 conjugation and deconjugation and found that the Plasmodium parasite consists of both activities. We successfully disrupted the genes individually; however, simultaneously, they were refractory to deletion and essential for parasite survival. Mutants lacking Atg4 and Otu showed normal blood and mosquito stage development. All mice infected with Otu KO sporozoites became patent; however, Atg4 KO sporozoites either failed to establish blood infection or showed delayed patency. Through in vitro and in vivo analysis, we found that Atg4 KO sporozoites invade and normally develop into early liver stages. However, nuclear and organelle differentiation was severely hampered during late stages and failed to mature into hepatic merozoites. We found a higher level of Atg8 in Atg4 KO parasites, and the deconjugation of Atg8 was hampered. We confirmed Otu localization on the apicoplast; however, parasites lacking Otu showed no visible developmental defects. Our data suggest that Atg4 is the primary deconjugating enzyme and that Otu cannot replace its function completely because it cleaves the peptide bond at the N-terminal side of glycine, thereby irreversibly inactivating Atg8 during its recycling. These findings highlight a role for the Atg8 deconjugation pathway in organelle biogenesis and maintenance of the homeostatic cellular balance.
Topics: Animals; Mice; Cysteine Proteases; Parasites; Plasmodium berghei; Autophagy-Related Protein 8 Family; Autophagy; Malaria; Protozoan Proteins
PubMed: 37910326
DOI: 10.1007/s00018-023-05004-2 -
Journal of Hazardous Materials Sep 2023Copper (Cu) pollution has become a serious environmental problem especially in recent decades. In this study, the mechanisms of Bacillus coagulans (Weizmannia coagulans)...
Copper (Cu) pollution has become a serious environmental problem especially in recent decades. In this study, the mechanisms of Bacillus coagulans (Weizmannia coagulans) XY2 against Cu-induced oxidative stress were explored through a dual model. In mice, Cu disturbed microbial community structure, revealing an increased level of Enterorhabdus abundance and decreased levels of Intestinimonas, Faecalibaculu, Ruminococcaceae and Coriobacteriaceae_UCG-002 abundance. Meanwhile, B. coagulans (W. coagulans) XY2 intervention reversed this trend along with alleviated Cu-induced metabolic disturbances by increasing levels of hypotaurine and L-glutamate and declining levels of phosphatidylcholine and phosphatidylethanolamine. In Caenorhabditis elegans, nuclear translocation of DAF-16 and SKN-1 was inhibited by Cu, which in turn suppressed antioxidant-related enzymes activities. XY2 mitigated biotoxicity associated with oxidative damage caused by Cu exposure via regulating DAF-16/FoxO and SKN-1/Nrf2 pathways and intestinal flora to eliminate excess ROS. Our study provides a theoretical basis formulating future strategy of probiotics against heavy metal contamination.
Topics: Bacillus; Male; Animals; Mice; Gastrointestinal Microbiome; Copper; Caenorhabditis elegans; Antioxidants; Oxidative Stress; Metabolic Networks and Pathways; Probiotics; Mice, Inbred C57BL
PubMed: 37270965
DOI: 10.1016/j.jhazmat.2023.131741 -
Archives of Microbiology Feb 2024An aerobic bacterium, designated as PT-12, was isolated from soil collected from agriculture field, and its taxonomic position was validated through a comprehensive...
An aerobic bacterium, designated as PT-12, was isolated from soil collected from agriculture field, and its taxonomic position was validated through a comprehensive polyphasic methodology. The strain was identified as Gram-stain-negative, non-motile, rod-shaped, and catalase- and oxidase-positive. The yellow-colored colonies showed growth ability at temperature range of 18-37 °C, NaCl content of 0-1.0% (w/v), and at a pH of 6.0-8.0. The 16S rRNA gene and phylogenetic analysis showed that strain PT-12 affiliated with the genus Sphingomonas in the family Sphingomonadaceae, and displayed the highest 16S rRNA nucleotide sequence similarity with Sphingomonas limnosediminicola 03SUJ6 (98.4%). The genome size of strain PT-12 was 2,656,862 bp and the DNA G + C content estimated from genome was 63.5%. The highest values of average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) were observed between strain PT-12 and Sphingomonas segetis YJ09, accounting to 76.2% and 20.2%, respectively. In addition, both ANI and dDDH values between strain PT-12 and other phylogenetically related neighbors ranged between 69.6% and 76.2% and 18.4% and 20.2%, respectively. Chemotaxonomic features exhibited Q-10 as the only ubiquinone; homospermidine as the major polyamine; summed feature 8 (Cω7c and/or Cω6c), C, and 10-methyl C as the notable fatty acids; and phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, and sphingoglycolipid as dominating polar lipids. Overall, the comprehensive polyphasic data supported that strain PT-12 represents a novel bacterial species within the genus Sphingomonas. Accordingly, we propose the name Sphingomonas flavescens sp. nov. The type strain is PT-12 (= KCTC 92114 = NBRC 115717).
Topics: Phospholipids; Sphingomonas; Phylogeny; RNA, Ribosomal, 16S; Soil; Bacterial Typing Techniques; DNA, Bacterial; Spermidine; Soil Microbiology; Fatty Acids; Sequence Analysis, DNA
PubMed: 38396312
DOI: 10.1007/s00203-024-03851-6 -
Angewandte Chemie (International Ed. in... Feb 2024The vast majority of membrane phospholipids (PLs) include two asymmetrically positioned fatty acyls: oxidizable polyunsaturated fatty acids (PUFA) attached predominantly...
Strikingly High Activity of 15-Lipoxygenase Towards Di-Polyunsaturated Arachidonoyl/Adrenoyl-Phosphatidylethanolamines Generates Peroxidation Signals of Ferroptotic Cell Death.
The vast majority of membrane phospholipids (PLs) include two asymmetrically positioned fatty acyls: oxidizable polyunsaturated fatty acids (PUFA) attached predominantly at the sn2 position, and non-oxidizable saturated/monounsaturated acids (SFA/MUFA) localized at the sn1 position. The peroxidation of PUFA-PLs, particularly sn2-arachidonoyl(AA)- and sn2-adrenoyl(AdA)-containing phosphatidylethanolamines (PE), has been associated with the execution of ferroptosis, a program of regulated cell death. There is a minor subpopulation (≈1-2 mol %) of doubly PUFA-acylated phospholipids (di-PUFA-PLs) whose role in ferroptosis remains enigmatic. Here we report that 15-lipoxygenase (15LOX) exhibits unexpectedly high pro-ferroptotic peroxidation activity towards di-PUFA-PEs. We revealed that peroxidation of several molecular species of di-PUFA-PEs occurred early in ferroptosis. Ferrostatin-1, a typical ferroptosis inhibitor, effectively prevented peroxidation of di-PUFA-PEs. Furthermore, co-incubation of cells with di-AA-PE and 15LOX produced PUFA-PE peroxidation and induced ferroptotic death. The decreased contents of di-PUFA-PEs in ACSL4 KO A375 cells was associated with lower levels of di-PUFA-PE peroxidation and enhanced resistance to ferroptosis. Thus, di-PUFA-PE species are newly identified phospholipid peroxidation substrates and regulators of ferroptosis, representing a promising therapeutic target for many diseases related to ferroptotic death.
Topics: Phosphatidylethanolamines; Arachidonate 15-Lipoxygenase; Cell Death; Phospholipids; Fatty Acids, Unsaturated; Lipid Peroxidation
PubMed: 38230815
DOI: 10.1002/anie.202314710 -
Nature May 2024Phosphatidylcholine and phosphatidylethanolamine, the two most abundant phospholipids in mammalian cells, are synthesized de novo by the Kennedy pathway from choline and...
Phosphatidylcholine and phosphatidylethanolamine, the two most abundant phospholipids in mammalian cells, are synthesized de novo by the Kennedy pathway from choline and ethanolamine, respectively. Despite the essential roles of these lipids, the mechanisms that enable the cellular uptake of choline and ethanolamine remain unknown. Here we show that the protein encoded by FLVCR1, whose mutation leads to the neurodegenerative syndrome posterior column ataxia and retinitis pigmentosa, transports extracellular choline and ethanolamine into cells for phosphorylation by downstream kinases to initiate the Kennedy pathway. Structures of FLVCR1 in the presence of choline and ethanolamine reveal that both metabolites bind to a common binding site comprising aromatic and polar residues. Despite binding to a common site, FLVCR1 interacts in different ways with the larger quaternary amine of choline in and with the primary amine of ethanolamine. Structure-guided mutagenesis identified residues that are crucial for the transport of ethanolamine, but dispensable for choline transport, enabling functional separation of the entry points into the two branches of the Kennedy pathway. Altogether, these studies reveal how FLVCR1 is a high-affinity metabolite transporter that serves as the common origin for phospholipid biosynthesis by two branches of the Kennedy pathway.
Topics: Humans; Binding Sites; Biological Transport; Choline; Ethanolamine; Membrane Transport Proteins; Models, Molecular; Phosphatidylcholines; Phosphatidylethanolamines; Phosphorylation; Mutagenesis
PubMed: 38693265
DOI: 10.1038/s41586-024-07374-4 -
International Journal of Systematic and... Aug 2023A facultative anaerobic, Gram-stain-negative rod-shaped bacterium, designated R, was isolated from the faecal material of a rabbit (). The strain could not be identified...
A facultative anaerobic, Gram-stain-negative rod-shaped bacterium, designated R, was isolated from the faecal material of a rabbit (). The strain could not be identified using an MALDI Biotyper sirius CA System. The closest matches based on the Bruker library were members of the genera and . However, the score value was in the range of no organism identification possible. Based on pairwise of 16S rRNA gene sequence analysis, the isolate was found to be a member of the family . The highest sequence similarities were found to the sequences of LMG 26273 (98.7 %), NBRC 102595 (98.5 %) and 090008 (98.4 %). Phylogenetic and whole genome analysis demonstrated that strain R represents a novel species within the genus . The predominant cellular fatty acids of strain R were C and products present in summed feature 2 (C) aldehyde, summed feature 3 (C ω6 and/or Cω7) and summed feature 8 (C ω7 and/or C ω6). genome analysis showed the presence of enzymes required for production of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol and phosphatidylserine. The G+C content determined from the genome was 54.94 mol %. Based on biochemical, phylogenetic, genotypic and chemotaxonomic criteria, the isolate represents a novel species of the genus for which the name sp. nov. is proposed. The type strain is strain R (=CCUG 76269=ATCC TSD-291).
Topics: Animals; Rabbits; Fatty Acids; Phospholipids; Pantoea; Ubiquinone; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA; Base Composition; DNA, Bacterial; Bacterial Typing Techniques
PubMed: 37535055
DOI: 10.1099/ijsem.0.005968 -
Free Radical Biology & Medicine Nov 2023Oxidized low-density lipoprotein (OX-LDL)-induced inflammation and autophagy dysregulation are important events in the progression of atherosclerosis....
Oxidized low-density lipoprotein (OX-LDL)-induced inflammation and autophagy dysregulation are important events in the progression of atherosclerosis. Phosphatidylethanolamine (PE), a multifunctional phospholipid that is enriched in cells, has been proven to be directly involved in autophagy which is closely associated with inflammation. However, whether PE can influence OX-LDL-induced autophagy dysregulation and inflammation has not been reported. In the present study, we revealed that OX-LDL significantly induced macrophage inflammation through the CD36-NLRP1-caspase-1 signaling pathway in fish. Meanwhile, cellular PE levels were significantly decreased in response to OX-LDL induction. Based on the relationship between PE and autophagy, we then examined the effect of PE supplementation on OX-LDL-mediated autophagy impairment and inflammation induction in macrophages. As expected, exogenous PE restored impaired autophagy and alleviated inflammation in OX-LDL-stimulated cells. Notably, autophagy inhibitors reversed the inhibitory effect of PE on OX-LDL-induced maturation of IL-1β, indicating that the regulation of PE on OX-LDL-induced inflammation is dependent on autophagy. Furthermore, the positive effect of PE on OX-LDL-induced inflammation was relatively conserved in mouse and fish macrophages. In conclusion, we elucidated the role of the CD36-NLRP1-caspase-1 signaling pathway in OX-LDL-induced inflammation in fish and revealed for the first time that altering PE abundance in OX-LDL-treated cells could alleviate inflammasome-mediated inflammation by inducing autophagy. Given the relationship between OX-LDL-induced inflammation and atherosclerosis, this study prompts that the use of PE-rich foods promises to be a new strategy for atherosclerosis treatment in vertebrates.
Topics: Animals; Mice; Atherosclerosis; Autophagy; Caspase 1; Inflammasomes; Inflammation; Lipoproteins, LDL; Macrophages; Phosphatidylethanolamines
PubMed: 37660837
DOI: 10.1016/j.freeradbiomed.2023.08.031 -
Frontiers in Cell and Developmental... 2023The TLC Domain Containing 1 (TLCD1) protein, a key regulator of phosphatidylethanolamine (PE) composition, is distributed across several cellular membranes, including...
The TLC Domain Containing 1 (TLCD1) protein, a key regulator of phosphatidylethanolamine (PE) composition, is distributed across several cellular membranes, including mitochondrial plasma membranes. Existing research has revealed the impact of TLCD1 on the development of non-alcoholic fatty liver disease. However, there remains a gap in comprehensive pan-cancer analyses of TLCD1, and the precise role of TLCD1 in cancer patient prognosis and immunological responses remains elusive. This study aims to provide a comprehensive visualization of the prognostic landscape associated with TLCD1 across a spectrum of cancers, while shedding light on the potential links between TLCD1 expression within the tumor microenvironment and immune infiltration characteristics. TLCD1 expression data were obtained from GTEx, TCGA, and HPA data repositories. Multiple databases including TIMER, HPA, TISIDB, cBioPortal, GEPIA2, STRING, KEGG, GO, and CancerSEA were used to investigate the expression pattern, diagnostic and prognostic significance, mutation status, functional analysis, and functional status of TLCD1. In addition, we evaluated the relationship between TLCD1 expression and immune infiltration, tumor mutational burden (TMB), microsatellite instability (MSI), and immune-related genes in pan-cancer. Furthermore, the association of TLCD1 with drug sensitivity was analyzed using the CellMiner database. We found that TLCD1 is generally highly expressed in pan-cancers and is significantly associated with the staging and prognosis of various cancers. Furthermore, our results also showed that TLCD1 was significantly associated with immune cell infiltration and immune regulatory factor expression. Using CellMiner database analysis, we then found a strong correlation between TLCD1 expression and sensitivity to anticancer drugs, indicating its potential as a therapeutic target. The most exciting finding is that high TLCD1 expression is associated with worse survival and prognosis in GBM and SKCM patients receiving anti-PD1 therapy. These findings highlight the potential of TLCD1 as a predictive biomarker for response to immunotherapy. TLCD1 plays a role in the regulation of immune infiltration and affects the prognosis of patients with various cancers. It serves as both a prognostic and immunologic biomarker in human cancer.
PubMed: 38559424
DOI: 10.3389/fcell.2023.1305906 -
Journal of Biochemistry Jun 2024Chondroitin sulfate (CS) is a linear polysaccharide chain of alternating residues of glucuronic acid (GlcA) and N-acetylgalactosamine (GalNAc), modified with sulfate...
Chondroitin sulfate (CS) is a linear polysaccharide chain of alternating residues of glucuronic acid (GlcA) and N-acetylgalactosamine (GalNAc), modified with sulfate groups. Based on the structure, CS chains bind to bioactive molecules specifically and regulate their functions. For example, CS whose GalNAc is sulfated at the C4 position, termed CSA, and CS whose GalNAc is sulfated at both C4 and C6 positions, termed CSE, bind to a malaria protein VAR2CSA and receptor type of protein tyrosine phosphatase sigma (RPTPσ), respectively in a specific manner. Here, we modified CSA and CSE chains with phosphatidylethanolamine (PE) at a reducing end, attached them to liposomes containing phospholipids, and generated CSA- and CSE-liposomes. The CS-PE was incorporated into the liposome particles efficiently. Inhibition ELISA revealed specific interaction of CSA and CSE with recombinant VAR2CSA and RPTPσ, respectively, more efficiently than CS chains alone. Furthermore, CSE-liposome was specifically incorporated into RPTPσ-expressing HEK293T cells. These results indicate CS-liposome as a novel and efficient drug delivery system, especially for CS-binding molecules.
PubMed: 38861406
DOI: 10.1093/jb/mvae041 -
Autophagy Oct 2023Macroautophagy/autophagy is a highly conserved pathway of cellular degradation and recycling that maintains cell health during homeostatic conditions and facilitates...
Macroautophagy/autophagy is a highly conserved pathway of cellular degradation and recycling that maintains cell health during homeostatic conditions and facilitates survival during stress. Aberrant cellular autophagy contributes to the pathogenesis of human diseases such as cancer, neurodegeneration, and cardiovascular, metabolic and lysosomal storage disorders. Despite decades of research, there remain unanswered questions as to how autophagy modulates cellular metabolism, and, conversely, how cellular metabolism affects autophagy activity. Here, we have identified the yeast metabolic transcription factor Stb5 as a negative regulator of autophagy. Chromosomal deletion of in the yeast enhances autophagy. Loss of Stb5 results in the upregulation of select uophay-related () transcripts under nutrient-replete conditions; however, the Stb5-mediated impact on autophagy occurs primarily through its effect on genes involved in NADPH production and the pentose phosphate pathway. This work provides insight into the intersection of Stb5 as a transcription factor that regulates both cellular metabolic responses and autophagy activity.: bp, base pairs; ChIP, chromatin immunoprecipitation; G6PD, glucose-6-phosphate dehydrogenase; GFP, green fluorescent protein; IDR, intrinsically disordered region; NAD, nicotinamide adenine dinucleotide; NADP, nicotinamide adenine dinucleotide phosphate; NADPH, nicotinamide adenine dinucleotide phosphate (reduced); ORF, open reading frame; PA, protein A; PCR, polymerase chain reaction; PE, phosphatidylethanolamine; PPP, pentose phosphate pathway; prApe1, precursor aminopeptidase I; ROS, reactive oxygen species; RT-qPCR, real-time quantitative PCR; SD, standard deviation; TF, transcription factor; TOR, target of rapamycin; WT, wild-type.
Topics: Humans; Autophagy; Gene Expression Regulation, Fungal; NADP; Saccharomyces cerevisiae; Transcription Factors
PubMed: 37345792
DOI: 10.1080/15548627.2023.2228533