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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 -
Investigative Ophthalmology & Visual... Jul 2024Glucocorticoid-induced glaucoma (GIG) is a prevalent complication associated with glucocorticoids (GCs), resulting in irreversible blindness. GIG is characterized by the...
PURPOSE
Glucocorticoid-induced glaucoma (GIG) is a prevalent complication associated with glucocorticoids (GCs), resulting in irreversible blindness. GIG is characterized by the abnormal deposition of extracellular matrix (ECM) in the trabecular meshwork (TM), elevation of intraocular pressure (IOP), and loss of retinal ganglion cells (RGCs). The objective of this study is to investigate the effects of nicotinamide riboside (NR) on TM in GIG.
METHODS
Primary human TM cells (pHTMs) and C57BL/6J mice responsive to GCs were utilized to establish in vitro and in vivo GIG models, respectively. The study assessed the expression of ECM-related proteins in TM and the functions of pHTMs to reflect the effects of NR. Mitochondrial morphology and function were also examined in the GIG cell model. GIG progression was monitored through IOP, RGCs, and mitochondrial morphology. Intracellular nicotinamide adenine dinucleotide (NAD+) levels of pHTMs were enzymatically assayed.
RESULTS
NR significantly prevented the expression of ECM-related proteins and alleviated dysfunction in pHTMs after dexamethasone treatment. Importantly, NR protected damaged ATP synthesis, preventing overexpression of mitochondrial reactive oxygen species (ROS), and also protect against decreased mitochondrial membrane potential induced by GCs in vitro. In the GIG mouse model, NR partially prevented the elevation of IOP and the loss of RGCs. Furthermore, NR effectively suppressed the excessive expression of ECM-associated proteins and mitigated mitochondrial damage in vivo.
CONCLUSIONS
Based on the results, NR effectively enhances intracellular levels of NAD+, thereby mitigating abnormal ECM deposition and TM dysfunction in GIG by attenuating mitochondrial damage induced by GCs. Thus, NR has promising potential as a therapeutic candidate for GIG treatment.
Topics: Animals; Niacinamide; Pyridinium Compounds; Glucocorticoids; Mice, Inbred C57BL; Mitochondria; Mice; Glaucoma; Extracellular Matrix; Intraocular Pressure; Humans; Disease Models, Animal; Trabecular Meshwork; Cells, Cultured; Retinal Ganglion Cells; Reactive Oxygen Species; Dexamethasone; Male
PubMed: 38949632
DOI: 10.1167/iovs.65.8.1 -
Physiological Genomics Jul 2024Type 2 diabetes (T2D) is a common metabolic disease due to insufficient insulin secretion by pancreatic beta cells in the context of insulin resistance. Islet molecular...
Type 2 diabetes (T2D) is a common metabolic disease due to insufficient insulin secretion by pancreatic beta cells in the context of insulin resistance. Islet molecular pathology reveals a role for protein misfolding in beta cell dysfunction and loss with islet amyloid derived from islet amyloid polypeptide (IAPP), a protein co-expressed and co-secreted with insulin. The most toxic form of misfolded IAPP is intracellular membrane disruptive toxic oligomers present in beta cells in T2D and in beta cells of mice transgenic for human IAPP (hIAPP). Prior work revealed a high degree of overlap of transcriptional changes in islets from T2D and pre-diabetic 9-10-week-old mice transgenic for hIAPP with most changes being pro-survival adaptations and therefore of limited therapeutic guidance. Here we investigated islets from hIAPP transgenic mice at an earlier age (6 weeks) to screen for potential mediators of hIAPP toxicity that precede predominance of pro-survival signaling. We identified early suppression of cholesterol synthesis and trafficking along with aberrant intra-beta cell cholesterol and lipid deposits, and impaired cholesterol trafficking to cell membranes. These findings align with comparable lipid deposits present in beta cells in T2D and increased vulnerability to develop T2D in individuals taking medications that suppress cholesterol synthesis.
PubMed: 38949617
DOI: 10.1152/physiolgenomics.00029.2024 -
Molecular Plant-microbe Interactions :... Jul 2024Hemibiotrophic fungi in the genus employ a biotrophic phase invading host epidermal cells followed by a necrotrophic phase spreading through neighboring mesophyll and...
Hemibiotrophic fungi in the genus employ a biotrophic phase invading host epidermal cells followed by a necrotrophic phase spreading through neighboring mesophyll and epidermal cells. We used serial block face scanning electron microscopy (SBF-SEM) to compare subcellular changes that occur in (alfalfa) cotyledons during infection by (compatible on ) and (incompatible on ). Three-dimensional reconstruction of serial images revealed that alfalfa epidermal cells infected with undergo massive cytological changes during the first 60 hours following inoculation to accommodate extensive intracellular hyphal growth. Conversely, inoculation with the incompatible species resulted in no successful penetration events and frequent formation of papilla-like structures and cytoplasmic aggregates beneath attempted fungal penetration sites. Further analysis of the incompatible interaction using focused ion beam-scanning electron microcopy (FIB-SEM) revealed formation of large multivesicular body-like structures that appeared spherical and were not visible in compatible interactions. These structures often fused with the host plasma membrane, giving rise to paramural bodies that appeared to be releasing extracellular vesicles (EVs). Isolation of EVs from the apoplastic space of alfalfa leaves at 60h post inoculation showed significantly more vesicles secreted from alfalfa infected with incompatible fungus compared to compatible fungus, which in turn was more than produced by non-infected plants. Thus, the increased frequency of paramural bodies during incompatible interactions correlated with an increase in EV quantity in apoplastic wash fluids. Together, these results suggest that EVs and paramural bodies contribute to immunity during pathogen attack in alfalfa.
PubMed: 38949504
DOI: 10.1094/MPMI-04-24-0045-R -
Molecular Imaging and Radionuclide... Jun 2024We present the case of a patient with newly diagnosed high-risk prostate cancer. The patient underwent nephrectomy for renal cell carcinoma (RCC) in 2009. The...
We present the case of a patient with newly diagnosed high-risk prostate cancer. The patient underwent nephrectomy for renal cell carcinoma (RCC) in 2009. The prostate-specific membrane antigen (PSMA) scan revealed a primary tumor with seminal vessel involvement, PSMA-positive regional lymph nodes, several nodular lung lesions with mild PSMA uptake, PSMA-positive mediastinal lymph nodes, and a PSMA-positive mass in the pancreatic head. Ultrasound-guided biopsy was performed for the pancreatic lesions revealing metastasis from a RCC. Simultaneous treatment for prostate cancer and metastatic RCC was initiated. To separate metastatic sites for both primaries, we attempted to use fluorodeoxyglucose positron emission tomography/computed tomography, which was moderately positive for the pancreatic mass but not for the other locations. RCC is a Ga PSMA-positive tumor; the synchronous combination of RCC with prostate cancer can be confusing and requires more complex clinical interpretation.
PubMed: 38949477
DOI: 10.4274/mirt.galenos.2023.90582 -
Paths of least resistance: Unconventional effector secretion by fungal and oomycete plant pathogens.Molecular Plant-microbe Interactions :... Jul 2024Effector secretion by different routes mediates the molecular interplay between host plant and pathogen, but mechanistic details in eukaryotes are sparse. This may limit...
Effector secretion by different routes mediates the molecular interplay between host plant and pathogen, but mechanistic details in eukaryotes are sparse. This may limit the discovery of new effectors that could be utilized for improving host plant disease resistance. In fungi and oomycetes, apoplastic effectors are secreted via the conventional ER-Golgi pathway while cytoplasmic effectors are packaged into vesicles that bypass Golgi in an unconventional protein secretion (UPS) pathway. In , the Golgi bypass UPS pathway incorporates components of the exocyst complex and a t-SNARE, presumably to fuse Golgi bypass vesicles to the fungal plasma membrane. Upstream, cytoplasmic effector mRNA translation in requires the efficient decoding of AA-ending codons. This involves the modification of wobble uridines in the anticodon loop of cognate tRNAs and fine-tunes cytoplasmic effector translation and secretion rates to maintain biotrophic interfacial complex integrity and permit host infection. Thus, plant-fungal interface integrity is intimately tied to effector codon usage, a surprising constraint on pathogenicity. Here, we discuss these findings within the context of fungal and oomycete effector discovery, delivery, and function in host cells. We show how cracking the codon code for unconventional cytoplasmic effector secretion in has revealed AA-ending codon usage bias in cytoplasmic effector mRNAs across kingdoms, including within the RxLR-dEER motif-encoding sequence of a bona fide cytoplasmic effector, suggesting its subjection to translational speed control. By focusing on recent developments in understanding unconventional effector secretion, we draw attention to this important but understudied area of host-pathogen interactions.
PubMed: 38949402
DOI: 10.1094/MPMI-12-23-0212-CR -
Advanced Materials (Deerfield Beach,... Jun 2024Heart transplantation offers life-saving treatment for patients with end-stage heart failure; however, ischemia-reperfusion injury (IRI) and subsequent immune responses...
Heart transplantation offers life-saving treatment for patients with end-stage heart failure; however, ischemia-reperfusion injury (IRI) and subsequent immune responses remain significant challenges. Current therapies primarily target adaptive immunity, with limited options available for addressing IRI and innate immune activation. Although plant-derived vesicle-like nanoparticles show promise in managing diseases, their application in organ transplantation complications is unexplored. Here, this work develops a novel reactive oxygen species (ROS)-responsive multifunctional fusion extracellular nanovesicles carrying rapamycin (FNVs@RAPA) to address early IRI and Ly6CLy6G inflammatory macrophage-mediated rejection in heart transplantation. The FNVs comprise Exocarpium Citri grandis-derived extracellular nanovesicles with anti-inflammatory and antioxidant properties, and mesenchymal stem cell membrane-derived nanovesicles expressing calreticulin with macrophage-targeting ability. A novel ROS-responsive bio-orthogonal chemistry approach facilitates the active targeting delivery of FNVs@RAPA to the heart graft site, effectively alleviating IRI and promoting the polarization of Ly6CLy6G inflammatory macrophages toward an anti-inflammatory phenotype. Hence, FNVs@RAPA represents a promising therapeutic approach for mitigating early transplantation complications and immune rejection. The fusion-targeted delivery strategy offers superior heart graft site enrichment and macrophage-specific targeting, promising improved transplant outcomes.
PubMed: 38949397
DOI: 10.1002/adma.202406758 -
FASEB Journal : Official Publication of... Jul 2024Cancer metastasis is the leading cause of death for those afflicted with cancer. In cancer metastasis, the cancer cells break off from the primary tumor, penetrate... (Review)
Review
Cancer metastasis is the leading cause of death for those afflicted with cancer. In cancer metastasis, the cancer cells break off from the primary tumor, penetrate nearby blood vessels, and attach and extravasate out of the vessels to form secondary tumors at distant organs. This makes extravasation a critical step of the metastatic cascade. Herein, with a focus on triple-negative breast cancer, the role that the prospective secondary tumor microenvironment's mechanical properties play in circulating tumor cells' extravasation is reviewed. Specifically, the effects of the physically regulated vascular endothelial glycocalyx barrier element, vascular flow factors, and subendothelial extracellular matrix mechanical properties on cancer cell extravasation are examined. The ultimate goal of this review is to clarify the physical mechanisms that drive triple-negative breast cancer extravasation, as these mechanisms may be potential new targets for anti-metastasis therapy.
Topics: Glycocalyx; Humans; Triple Negative Breast Neoplasms; Female; Tumor Microenvironment; Animals; Neoplastic Cells, Circulating; Neoplasm Metastasis; Endothelium, Vascular
PubMed: 38949120
DOI: 10.1096/fj.202400380R -
The Journal of Clinical Investigation Jul 2024Ubiquitination plays an essential role in protein stability, subcellular localization, and interactions. Crosstalk between different types of ubiquitination results in...
Ubiquitination plays an essential role in protein stability, subcellular localization, and interactions. Crosstalk between different types of ubiquitination results in distinct biological outcomes for proteins. However, the role of ubiquitination-related crosstalk in lymph node (LN) metastasis and the key regulatory factors controlling this process have not been determined. Using high-throughput sequencing, we found that ubiquitin-conjugating enzyme E2 C (UBE2C) was overexpressed in bladder cancer (BCa) and was strongly associated with an unfavorable prognosis. Overexpression of UBE2C increased BCa lymphangiogenesis and promoted LN metastasis both in vitro and in vivo. Mechanistically, UBE2C mediated sodium-coupled neutral amino acid transporter 2 (SNAT2) monoubiquitination at lysine 59 to inhibit K63-linked polyubiquitination at lysine 33 of SNAT2. Crosstalk between monoubiquitination and K63-linked polyubiquitination increased SNAT2 membrane protein levels by suppressing epsin 1-mediated (EPN1-mediated) endocytosis. SNAT2 facilitated glutamine uptake and metabolism to promote VEGFC secretion, ultimately leading to lymphangiogenesis and LN metastasis in patients with BCa. Importantly, inhibition of UBE2C significantly attenuated BCa lymphangiogenesis in a patient-derived xenograft model. Our results reveal the mechanism by which UBE2C mediates crosstalk between the monoubiquitination and K63-linked polyubiquitination of SNAT2 to promote BCa metastasis and identify UBE2C as a promising target for treating LN-metastatic BCa.
Topics: Ubiquitin-Conjugating Enzymes; Humans; Ubiquitination; Urinary Bladder Neoplasms; Animals; Lymphatic Metastasis; Mice; Cell Line, Tumor; Lymphangiogenesis; Female; Male; Vascular Endothelial Growth Factor C; Neoplasm Proteins; Minor Histocompatibility Antigens; Amino Acid Transport System ASC
PubMed: 38949026
DOI: 10.1172/JCI179122 -
Small (Weinheim An Der Bergstrasse,... Jul 2024A cerebral ischemia-reperfusion injury is ensued by an intricate interplay between various pathological processes including excitotoxicity, oxidative stress,...
A cerebral ischemia-reperfusion injury is ensued by an intricate interplay between various pathological processes including excitotoxicity, oxidative stress, inflammation, and apoptosis. For a long time, drug intervention policies targeting a single signaling pathway have failed to achieve the anticipated clinical efficacy in the intricate and dynamic inflammatory environment of the brain. Moreover, inadequate targeted drug delivery remains a significant challenge in cerebral ischemia-reperfusion injury therapy. In this study, a multifunctional nanoplatform (designated as PB-006@MSC) is developed using ZL006-loaded Prussian blue nanoparticles (PBNPs) camouflaged by a mesenchymal stem cell (MSC) membrane (MSCm). ZL006 is a neuroprotectant. It can be loaded efficiently into the free radical scavenger PBNP through mesoporous adsorption. This can simultaneously modulate multiple targets and pathways. MSCm biomimetics can reduce the nanoparticle immunogenicity, efficiently enhance their homing capability to the cerebral ischemic penumbra, and realize active-targeting therapy for ischemic stroke. In animal experiments, PB-006@MSC integrated reactive oxygen species (ROS) scavenging and neuroprotection. Thereby, it selectively targeted the cerebral ischemic penumbra (about fourfold higher accumulation at 24 h than in the non-targeted group), demonstrated a remarkable therapeutic efficacy in reducing the volume of cerebral infarction (from 37.1% to 2.3%), protected the neurogenic functions, and ameliorated the mortality.
PubMed: 38948959
DOI: 10.1002/smll.202401045