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Science (New York, N.Y.) Mar 2024Cytoplasmic dynein is a microtubule motor vital for cellular organization and division. It functions as a ~4-megadalton complex containing its cofactor dynactin and a...
Cytoplasmic dynein is a microtubule motor vital for cellular organization and division. It functions as a ~4-megadalton complex containing its cofactor dynactin and a cargo-specific coiled-coil adaptor. However, how dynein and dynactin recognize diverse adaptors, how they interact with each other during complex formation, and the role of critical regulators such as lissencephaly-1 (LIS1) protein (LIS1) remain unclear. In this study, we determined the cryo-electron microscopy structure of dynein-dynactin on microtubules with LIS1 and the lysosomal adaptor JIP3. This structure reveals the molecular basis of interactions occurring during dynein activation. We show how JIP3 activates dynein despite its atypical architecture. Unexpectedly, LIS1 binds dynactin's p150 subunit, tethering it along the length of dynein. Our data suggest that LIS1 and p150 constrain dynein-dynactin to ensure efficient complex formation.
Topics: Cryoelectron Microscopy; Dynactin Complex; Dyneins; Microtubule-Associated Proteins; Microtubules; Protein Binding; Humans; HeLa Cells; 1-Alkyl-2-acetylglycerophosphocholine Esterase; Nerve Tissue Proteins; Adaptor Proteins, Signal Transducing; WD40 Repeats; Protein Interaction Mapping
PubMed: 38547289
DOI: 10.1126/science.adk8544 -
Drug Discovery Today May 2024Compared to other nanovectors, liposomes exhibit unique advantages, such as good biosafety and high drug-loading capacity. However, slow drug release from conventional... (Review)
Review
Compared to other nanovectors, liposomes exhibit unique advantages, such as good biosafety and high drug-loading capacity. However, slow drug release from conventional liposomes makes most payloads unavailable, restricting the therapeutic efficacy. Therefore, in the last ∼20 years, enzyme-responsive liposomes have been extensively investigated, which liberate drugs under the stimulation of enzymes overexpressed at disease sites. In this review, we elaborate on the research progress on enzyme-responsive liposomes. The involved enzymes mainly include phospholipases, particularly phospholipase A2, matrix metalloproteinases, cathepsins, and esterases. These enzymes can cleave ester bonds or specific peptide sequences incorporated in the liposomes for controlled drug release by disrupting the primary structure of liposomes, detaching protective polyethylene glycol shells, or activating liposome-associated prodrugs. Despite decades of efforts, there are still a lack marketed products of enzyme-responsive liposomes. Therefore, more efforts should be made to improve the safety and effectiveness of enzyme-responsive liposomes and address the issues associated with production scale-up.
PubMed: 38705509
DOI: 10.1016/j.drudis.2024.104014 -
American Journal of Kidney Diseases :... Mar 2024Rituximab is the first-choice therapy for patients with primary membranous nephropathy (MN) and nephrotic syndrome. However, approximately 30% of patients are...
RATIONALE & OBJECTIVE
Rituximab is the first-choice therapy for patients with primary membranous nephropathy (MN) and nephrotic syndrome. However, approximately 30% of patients are treatment-resistant or become treatment-intolerant with hypersensitivity reactions upon repeated drug exposures. We aimed to assess whether ofatumumab, a fully human second-generation anti-CD20 antibody, could be a valuable alternative to rituximab in this population.
STUDY DESIGN
Case series.
SETTING & PARTICIPANTS
7 rituximab-intolerant and 10 rituximab-resistant patients with MN who consented to receive ofatumumab (50-300mg, single intravenous infusion) and were followed at the nephrology unit of Azienda Socio-Sanitaria Territoriale Papa Giovanni XXIII (Bergamo, Italy) between September 2015 and January 2019.
FINDINGS
Over a median (IQR) follow-up of 5.0 (3.0-9.8) months, all 7 rituximab-intolerant and 3 of the 10 rituximab-resistant patients exhibited complete (proteinuria<0.3g/d) or partial (proteinuria<3.5g/d with≥50% reduction vs baseline) remission of nephrotic syndrome. Circulating B cells were similarly depleted in all patients by 1 week, and serum anti-phospholipase A receptor antibody concentrations decreased to<2.7 relative units/mL in 3 of 4 rituximab-intolerant and 4 of 8 rituximab-resistant patients with phospholipase A receptor-related disease. Ofatumumab significantly reduced 24-hour urinary protein and immunoglobulin G excretion and increased serum albumin and immunoglobulin G levels. These effects were greater in rituximab-intolerant than in rituximab-resistant patients. Measured glomerular filtration rate significantly increased by an average of 13.4% at 24 months compared with baseline (P=0.036) among all patients in the series. There were 14 nonserious infusion-related adverse events in 9 patients that recovered with temporary infusion interruption.
LIMITATIONS
Retrospective design, limited number of patients.
CONCLUSIONS
Ofatumumab may represent an effective and safe treatment for rituximab-intolerant cases of MN. Larger prospective studies will be needed to validate these preliminary findings and explore the effectiveness of other second-generation anti-CD20 antibodies in this clinical setting.
PLAIN-LANGUAGE SUMMARY
Primary membranous nephropathy (MN) is one of the most frequent causes of nephrotic syndrome (NS) in adults. In this case series, we explored the efficacy of ofatumumab, a fully human second-generation anti-CD20 antibody, in 17 patients with MN and NS who were intolerant or unresponsive to rituximab. All 7 rituximab-intolerant patients exhibited complete or partial clinical remission, compared with only 3 of the 10 rituximab-resistant patients. Autoantibody levels decreased in all patients with phospholipase A receptor-related disease. Ofatumumab achieved a significant reduction in urinary protein and immunoglobulin G excretion while increasing serum albumin and immunoglobulin G levels. Ofatumumab may be a promising option for patients with MN who are rituximab-intolerant. Further investigations are warranted to validate these preliminary findings.
Topics: Adult; Humans; Rituximab; Nephrotic Syndrome; Glomerulonephritis, Membranous; Retrospective Studies; Prospective Studies; Antibodies, Monoclonal, Humanized; Immunoglobulin G; Proteinuria; Serum Albumin; Phospholipases; Immunosuppressive Agents; Receptors, Phospholipase A2
PubMed: 37777061
DOI: 10.1053/j.ajkd.2023.08.010 -
Science Signaling Jul 2023Uncontrolled inflammation is linked to poor outcomes in sepsis and wound healing, both of which proceed through distinct inflammatory and resolution phases. Eicosanoids...
Uncontrolled inflammation is linked to poor outcomes in sepsis and wound healing, both of which proceed through distinct inflammatory and resolution phases. Eicosanoids are a class of bioactive lipids that recruit neutrophils and other innate immune cells. The interaction of ceramide 1-phosphate (C1P) with the eicosanoid biosynthetic enzyme cytosolic phospholipase A (cPLA) reduces the production of a subtype of eicosanoids called oxoeicosanoids. We investigated the effect of shifting the balance in eicosanoid biosynthesis on neutrophil polarization and function. Knockin mice expressing a cPLA mutant lacking the C1P binding site (α mice) showed enhanced and sustained neutrophil infiltration into wounds and the peritoneum during the inflammatory phase of wound healing and sepsis, respectively. The mice exhibited improved wound healing and reduced susceptibility to sepsis, which was associated with an increase in anti-inflammatory N2-type neutrophils demonstrating proresolution behaviors and a decrease in proinflammatory N1-type neutrophils. The N2 polarization of α neutrophils resulted from increased oxoeicosanoid biosynthesis and autocrine signaling through the oxoeicosanoid receptor OXER1 and partially depended on OXER1-dependent inhibition of the pentose phosphate pathway (PPP). Thus, C1P binding to cPLAα suppresses neutrophil N2 polarization, thereby impairing wound healing and the response to sepsis.
Topics: Animals; Mice; Neutrophils; Sepsis; Autocrine Communication; Group IV Phospholipases A2; Inflammation
PubMed: 37433004
DOI: 10.1126/scisignal.add6527 -
Medicine Nov 2023To investigate the risk factors for acute ischemic stroke (AIS) in patients with type 2 diabetes mellitus (T2DM) patients. a total of 120 T2DM patients who met the... (Randomized Controlled Trial)
Randomized Controlled Trial
To investigate the risk factors for acute ischemic stroke (AIS) in patients with type 2 diabetes mellitus (T2DM) patients. a total of 120 T2DM patients who met the inclusion and exclusion criteria, from between January 2021 to June 2022, were randomly selected and divided into T2DM and T2DM + AIS groups based on the presence or absence of a history of AIS. Blood samples were collected by fasting, 24 hours after admission, and levels of serum uric acid (UA), serum homocysteine (Hcy), serum creatinine (SCR), blood urea nitrogen (BUN), fasting blood glucose (FBG), glycated hemoglobin A1c (HbA1c), serum total cholesterol (TC), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, high-sensitivity C-reactive protein (hs-CRP), and lipoprotein-associated phospholipase A2 (Lp-PLA2) were measured. Multivariate logistic regression analysis was performed for the significantly associated indicators to analyze the risk factors for AIS, and finally ROC curve analysis was carried out to explore the predictive value of the above risk factors for AIS in T2DM patients. the levels of FBG, Hcy, Hs-CRP and Lp-PLA2 were significantly higher in the T2DM + AIS group than those in T2DM group (P < .05). Multivariate logistic regression analysis revealed that hs-CRP and Lp-PLA2 were independent risk factors for the development of AIS in patients with T2DM with an OR of 2.85 (95% CI: 1.26-6.43, P = .012) and 3.64 (95% CI: 1.63-8.12, P = .002), respectively. ROC curve analysis showed that plasma hs-CRP and Lp-PLA2 showed good performance to predict AIS occurrence in T2DM patients (AUC = 0.749, 95% CI: 0.663, 0.835; and 0.791, 95% CI: 0.712, 0.870), with a sensitivity of 58.1% and 83.9%, and a specificity of 84.5% and 60.3%, respectively. The optimal concentration cutoff points of hs-CRP and Lp-PLA2 were 3.38 mg/L and 204.2 ng/mL. our findings suggested that plasma hs-CRP and Lp-PLA2 were independent risk factors for developing AIS in T2DM patients. Hs-CRP and Lp-PLA2 are potential biomarker for risk for AIS in patients with T2DM.
Topics: Humans; Diabetes Mellitus, Type 2; C-Reactive Protein; 1-Alkyl-2-acetylglycerophosphocholine Esterase; Ischemic Stroke; Uric Acid; Risk Factors; Biomarkers; Cholesterol, LDL; Stroke
PubMed: 38013286
DOI: 10.1097/MD.0000000000036114 -
Nature Chemistry Jul 2023Cellular membranes contain numerous lipid species, and efforts to understand the biological functions of individual lipids have been stymied by a lack of approaches for...
Cellular membranes contain numerous lipid species, and efforts to understand the biological functions of individual lipids have been stymied by a lack of approaches for controlled modulation of membrane composition in situ. Here we present a strategy for editing phospholipids, the most abundant lipids in biological membranes. Our membrane editor is based on a bacterial phospholipase D (PLD), which exchanges phospholipid head groups through hydrolysis or transphosphatidylation of phosphatidylcholine with water or exogenous alcohols. Exploiting activity-dependent directed enzyme evolution in mammalian cells, we have developed and structurally characterized a family of 'superPLDs' with up to a 100-fold enhancement in intracellular activity. We demonstrate the utility of superPLDs for both optogenetics-enabled editing of phospholipids within specific organelle membranes in live cells and biocatalytic synthesis of natural and unnatural designer phospholipids in vitro. Beyond the superPLDs, activity-based directed enzyme evolution in mammalian cells is a generalizable approach to engineer additional chemoenzymatic biomolecule editors.
Topics: Animals; Phospholipids; Phosphatidylcholines; Cell Membrane; Phospholipase D; Hydrolysis; Mammals
PubMed: 37217787
DOI: 10.1038/s41557-023-01214-0 -
ACS Synthetic Biology Jan 2024Cells experience time-varying and spatially heterogeneous chemokine signals , activating cell surface proteins including G protein-coupled receptors (GPCRs). The Gαq...
Cells experience time-varying and spatially heterogeneous chemokine signals , activating cell surface proteins including G protein-coupled receptors (GPCRs). The Gαq pathway activation by GPCRs is a major signaling axis with broad physiological and pathological significance. Compared with other Gα members, GαqGTP activates many crucial effectors, including PLCβ (Phospholipase Cβ) and Rho GEFs (Rho guanine nucleotide exchange factors). PLCβ regulates many key processes, such as hematopoiesis, synaptogenesis, and cell cycle, and is therefore implicated in terminal-debilitating diseases, including cancer, epilepsy, Huntington's Disease, and Alzheimer's Disease. However, due to a lack of genetic and pharmacological tools, examining how the dynamic regulation of PLCβ signaling controls cellular physiology has been difficult. Since activated PLCβ induces several abrupt cellular changes, including cell morphology, examining how the other pathways downstream of Gq-GPCRs contribute to the overall signaling has also been difficult. Here we show the engineering, validation, and application of a highly selective and efficient optogenetic inhibitor (Opto-dHTH) to completely disrupt GαqGTP-PLCβ interactions reversibly in user-defined cellular-subcellular regions on optical command. Using this newly gained PLCβ signaling control, our data indicate that the molecular competition between RhoGEFs and PLCβ for GαqGTP determines the potency of Gq-GPCR-governed directional cell migration.
Topics: Phospholipase C beta; Signal Transduction
PubMed: 38092428
DOI: 10.1021/acssynbio.3c00490 -
Molecular Cell Apr 2024Batten disease, the most prevalent form of neurodegeneration in children, is caused by mutations in the CLN3 gene, which encodes a lysosomal transmembrane protein. CLN3...
Batten disease, the most prevalent form of neurodegeneration in children, is caused by mutations in the CLN3 gene, which encodes a lysosomal transmembrane protein. CLN3 loss leads to significant accumulation of glycerophosphodiesters (GPDs), the end products of glycerophospholipid catabolism in the lysosome. Despite GPD storage being robustly observed upon CLN3 loss, the role of GPDs in neuropathology remains unclear. Here, we demonstrate that GPDs act as potent inhibitors of glycerophospholipid catabolism in the lysosome using human cell lines and mouse models. Mechanistically, GPDs bind and competitively inhibit the lysosomal phospholipases PLA2G15 and PLBD2, which we establish to possess phospholipase B activity. GPDs effectively inhibit the rate-limiting lysophospholipase activity of these phospholipases. Consistently, lysosomes of CLN3-deficient cells and tissues accumulate toxic lysophospholipids. Our work establishes that the storage material in Batten disease directly disrupts lysosomal lipid homeostasis, suggesting GPD clearance as a potential therapeutic approach to this fatal disease.
Topics: Mice; Animals; Child; Humans; Membrane Glycoproteins; Molecular Chaperones; Neuronal Ceroid-Lipofuscinoses; Lysosomes; Phospholipases; Glycerophospholipids; Phospholipids
PubMed: 38447580
DOI: 10.1016/j.molcel.2024.02.006 -
Toxicon : Official Journal of the... Sep 2023Research on centipede venoms has led to the discovery of a diverse array of novel proteins and peptides, including those with homology to previously discovered toxin...
Research on centipede venoms has led to the discovery of a diverse array of novel proteins and peptides, including those with homology to previously discovered toxin families (e.g., phospholipase A2s and pM12a metalloproteases) and novel toxin families not previously detected in venoms (e.g., β-pore forming toxins and scoloptoxins). Most of this research has focused on centipedes in the order Scolopendromorpha, particularly those in the families Scolopendridae, Cryptopidae, and Scolopocryptopidae. To generate the first high-throughput venom characterization for a centipede in the scolopendromorph family Plutoniumidae, we performed venom-gland transcriptomics and venom proteomics on two Theatops posticus. We identified a total of 64 venom toxins, 60 of which were detected in both the venom-gland transcriptome and venom proteome and four of which were only detected transcriptomically. We detected a single highly abundant arylsulfatase B (ARSB) toxin, the first ARSB toxin identified from centipede venoms. As ARSBs have been detected in other venomous species (e.g., scorpions), ARSBs in T. posticus highlights a new case of convergent evolution across venoms. Theatops posticus venom also contained a much higher abundance and diversity of phospholipase A2 toxins compared to other characterized centipede venoms. Conversely, we detected other common centipedes toxins, such as CAPs and scoloptoxins, at relatively low abundances and diversities. Our observation of a diverse set of toxins from T. posticus venom, including those from novel toxin families, emphasizes the importance of studying unexplored centipede taxonomic groups and the continued potential of centipede venoms for novel toxin discovery and unraveling the molecular mechanisms underlying trait evolution.
Topics: Animals; Chilopoda; Arthropods; Arylsulfatases; Phospholipases; Arthropod Venoms; Transcriptome
PubMed: 37517595
DOI: 10.1016/j.toxicon.2023.107231 -
Experimental Parasitology Dec 2023The free-living protozoan Acanthamoeba can cause severe keratitis known as Acanthamoeba Keratitis (AK) and granulomatous amoebic encephalitis (GAE). The pathogenesis of...
INTRODUCTION
The free-living protozoan Acanthamoeba can cause severe keratitis known as Acanthamoeba Keratitis (AK) and granulomatous amoebic encephalitis (GAE). The pathogenesis of Acanthamoeba includes intricate interactions between the organism and the host's immune system. The downstream analysis of a well-annotated genome assembly along with proteomic analysis can unravel several biological processes and aid in the identification of potential genes involved in pathogenicity.
METHODS
Based on the next-generation sequencing data analysis, genes including lysophospholipase, phospholipase, S8/S53 peptidase, carboxylesterase, and mannose-binding protein were selected as probable pathogenic targets that were validated by conventional PCR in a total of 30 Acanthamoeba isolates. This was followed by real-time PCR for the evaluation of relative gene expression in the keratitis and amoebic encephalitis animal model induced using keratitis (CHA5), encephalitis (CHA24) and non-pathogenic environmental isolate (CHA36). In addition, liquid chromatography-mass spectrometry (LC-MS/MS) was performed for keratitis, encephalitis, and non-pathogenic environmental isolate before and after treatment with polyhexamethylene biguanide (PHMB).
RESULTS
The conventional PCR demonstrated the successful amplification of lysophospholipase, phospholipase, S8/S53 peptidase, carboxylesterase, and mannose-binding protein genes in clinical and environmental isolates. The expression analysis revealed phospholipase, lysophospholipase, and mannose-binding genes to be significantly upregulated in the keratitis isolate (CHA 5) during AK in the animal model. In the case of the amoebic encephalitis model, phospholipase, lysophospholipase, S8/S53 peptidase, and carboxylesterase were significantly upregulated in the encephalitis isolate compared to the keratitis isolate. The proteomic data revealed differential protein expression in pathogenic versus non-pathogenic isolates in the pre and post-treatment with PHMB.
CONCLUSION
The gene expression data suggests that lysophospholipase, phospholipase, S8/S53 peptidase, carboxylesterase, and mannose-binding protein (MBP) could play a role in the contact-dependent and independent mechanisms of Acanthamoeba pathogenesis. In addition, the proteomic profiling of the 3 isolates revealed differential protein expression crucial for parasite growth, survival, and virulence. Our results provide baseline data for selecting possible pathogenic targets that could be utilized for designing knockout experiments in the future.
Topics: Animals; Acanthamoeba; Mannose-Binding Lectin; Lysophospholipase; Chromatography, Liquid; Proteomics; Tandem Mass Spectrometry; Acanthamoeba Keratitis; Amebiasis; Encephalitis; Real-Time Polymerase Chain Reaction; Gene Expression; Peptide Hydrolases
PubMed: 37820893
DOI: 10.1016/j.exppara.2023.108630