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Advances in Virus Research 2024The surfaces of cells and enveloped viruses alike are coated in carbohydrates that play multifarious roles in infection and immunity. Organisms across all kingdoms of... (Review)
Review
The surfaces of cells and enveloped viruses alike are coated in carbohydrates that play multifarious roles in infection and immunity. Organisms across all kingdoms of life make use of a diverse set of monosaccharide subunits, glycosidic linkages, and branching patterns to encode information within glycans. Accordingly, sugar-patterning enzymes and glycan binding proteins play integral roles in cell and organismal biology, ranging from glycoprotein quality control within the endoplasmic reticulum to lymphocyte migration, coagulation, inflammation, and tissue homeostasis. Unsurprisingly, genes involved in generating and recognizing oligosaccharide patterns are playgrounds for evolutionary conflicts that abound in cross-species interactions, exemplified by the myriad plant lectins that function as toxins. In vertebrates, glycans bearing acidic nine-carbon sugars called sialic acids are key regulators of immune responses. Various bacterial and fungal pathogens adorn their cells in sialic acids that either mimic their hosts' or are stolen from them. Yet, how viruses commandeer host sugar-patterning enzymes to thwart immune responses remains poorly studied. Here, we review examples of viruses that interact with sialic acid-binding immunoglobulin-like lectins (Siglecs), a family of immune cell receptors that regulate toll-like receptor signaling and govern glycoimmune checkpoints, while highlighting knowledge gaps that merit investigation. Efforts to illuminate how viruses leverage glycan-dependent checkpoints may translate into new clinical treatments that uncloak viral antigens and infected cell surfaces by removing or masking immunosuppressive sialoglycans, or by inhibiting viral gene products that induce their biosynthesis. Such approaches may hold the potential to unleash the immune system to clear long intractable chronic viral infections.
Topics: Glycocalyx; Humans; Animals; Viruses; Polysaccharides; Sialic Acid Binding Immunoglobulin-like Lectins; Virus Diseases; Host-Pathogen Interactions
PubMed: 38897709
DOI: 10.1016/bs.aivir.2024.03.001 -
The Journal of Investigative Dermatology Jun 2024RAS proteins regulate cell division, differentiation and apoptosis via multiple downstream effector pathways. Oncogenic RAS variants are the commonest drivers in...
RAS proteins regulate cell division, differentiation and apoptosis via multiple downstream effector pathways. Oncogenic RAS variants are the commonest drivers in cancers, however they also drive many benign lesions predisposing to malignancy, such as melanocytic naevi, thyroid nodules, and colonic polyps. Reversal of these benign lesions could reduce cancer incidence, however the effects of oncogenic RAS have been notoriously difficult to target with downstream pathway inhibitors. Here we show effective suppression of oncogenic and currently undruggable NRAS in primary cells from melanocytic naevi using siRNA targeted to the recurrent causal variant. This results in striking reduction in expression of ARL6IP1, a known inhibitor of endoplasmic reticulum stress-induced apoptosis not previously linked to NRAS. We go on to show that a single dose of siRNA in primary cells triggers an apoptotic cascade, in contrast to treatment with a MEK inhibitor. Protective packaging of the targeted siRNA into lipid nanoparticles permits successful delivery into a humanised mouse model of melanocytic naevi, and results in variant NRAS knockdown in vivo. These data show that RAS-induced protection from apoptosis is involved in persistence of NRAS-driven melanocytic naevi and anticipate that targeted siRNA could form the basis of clinical trials for RAS-driven benign tumours.
PubMed: 38897541
DOI: 10.1016/j.jid.2024.04.031 -
Journal of Advanced Research Jun 2024Chemoimmunotherapy, which benefits from the combination of chemotherapy and immunotherapy, has emerged as a promising strategy in cancer treatment. However, effectively...
INTRODUCTION
Chemoimmunotherapy, which benefits from the combination of chemotherapy and immunotherapy, has emerged as a promising strategy in cancer treatment. However, effectively inducing a robust immune response remains challenging due to the limited responsiveness across patients. Endoplasmic reticulum (ER) stress is essential for activating intracellular signaling pathways associated with immunogenic cell death (ICD), targeting drugs to ER might enhance ER stress and improve ICD-related immunotherapy.
OBJECTIVES
To improve the immune response of Chemoimmunotherapy.
METHODS
ER targeting nanoparticles TSE-CEL/NP were constructed to enhance immunogenic cancer cell death. Flow cytometry, confocal microscope, TEM and immunofluorescence were used to evaluate the ER targeting effect and immunogenic tumor cell death in vitro on B16F10 tumor cells. Unilateral and bilateral tumor models were constructed to investigate the efficacy of anti-tumor and immunotherapy in vivo. Lung metastasis B16F10 melanoma tumor-bearing mice were used to assess the anti-metastasis efficacy.
RESULTS
TSE-CEL/NP could specially accumulate in ER, thereby induce ER stress. High ER stress trigger the exposure of CRT, the extracellular release of HMGB1 and ATP. These danger signals subsequently promote the recruitment and maturation of dendritic cells (DCs), which in turn increase the proliferation of cytotoxic T lymphocytes (CD8 T cells), ultimately resulted in an improved immunotherapy efficacy against melanoma. Invivo experiments showed that TSE-CEL/NP exhibits excellent antitumor efficacy and triggers a strong immune response.
CONCLUSION
Our findings demonstrated that celastrol ER targeting delivery could amplify immunogenic cell death in melanoma, which provide experimental basis for melanoma immunotherapy.
PubMed: 38897272
DOI: 10.1016/j.jare.2024.06.011 -
ELife Jun 2024The protein translocon at the endoplasmic reticulum comprises the Sec61 translocation channel and numerous accessory factors that collectively facilitate the biogenesis...
The protein translocon at the endoplasmic reticulum comprises the Sec61 translocation channel and numerous accessory factors that collectively facilitate the biogenesis of secretory and membrane proteins. Here, we leveraged recent advances in cryo-electron microscopy (cryo-EM) and structure prediction to derive insights into several novel configurations of the ribosome-translocon complex. We show how a transmembrane domain (TMD) in a looped configuration passes through the Sec61 lateral gate during membrane insertion; how a nascent chain can bind and constrain the conformation of ribosomal protein uL22; and how the translocon-associated protein (TRAP) complex can adjust its position during different stages of protein biogenesis. Most unexpectedly, we find that a large proportion of translocon complexes contains RAMP4 intercalated into Sec61's lateral gate, widening Sec61's central pore and contributing to its hydrophilic interior. These structures lead to mechanistic hypotheses for translocon function and highlight a remarkably plastic machinery whose conformations and composition adjust dynamically to its diverse range of substrates.
Topics: Ribosomes; Cryoelectron Microscopy; SEC Translocation Channels; Endoplasmic Reticulum; Protein Conformation; Ribosomal Proteins; Humans; Models, Molecular; Protein Transport; Membrane Proteins
PubMed: 38896445
DOI: 10.7554/eLife.95814 -
Discover Oncology Jun 2024Pancreatic cancer-associated fibroblasts (CAFs) play a crucial role in tumor progression and immune evasion. Asperuloside (ASP) is an iridoid glycoside with potential...
BACKGROUND
Pancreatic cancer-associated fibroblasts (CAFs) play a crucial role in tumor progression and immune evasion. Asperuloside (ASP) is an iridoid glycoside with potential anti-tumor properties. This study aimed to explore the molecular mechanisms of ASP on CAFs, particularly focusing on its effects on activating transcription factor 6 (ATF6), a key regulator of endoplasmic reticulum stress.
METHOD
CAFs were treated with different concentrations of ASP (0, 1, 3, and 5 mM), and the role of ATF6 was investigated by over-expressing it in CAFs. Subsequently, western blot was used to detect ATF6, α-smooth muscle actin (α-SMA), fibroblast activating protein (FAP), and vimentin protein levels in CAFs. The collagen gel contraction assay and Transwell assay were applied to evaluate the contraction and migration ability of CAFs. In addition, the interleukin (IL)-6, C-C motif chemokine ligand (CCL)-2, and C-X-C motif chemokine ligand (CXCL)-10 levels were detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR).
RESULTS
CAFs had significantly higher expression levels of α-SMA, FAP, and vimentin compared to normal fibroblasts (NFs). ASP significantly inhibited the activation, contraction, and migration of CAFs in a concentration-dependent manner. ASP treatment also reduced the expression of cytokines (IL-6, CCL2, and CXCL10) and down-regulated ATF6 levels. Over-expression of ATF6 mitigated the inhibitory effects of ASP.
CONCLUSION
ASP exerts its anti-tumor effects by down-regulating ATF6, thereby inhibiting the activation and function of pancreatic CAFs. These findings suggest that ASP could be a promising therapeutic agent for pancreatic cancer by modulating the tumor microenvironment.
PubMed: 38896161
DOI: 10.1007/s12672-024-01095-w -
Applied Microbiology and Biotechnology Jun 2024Chinese hamster ovary (CHO) cells are popular in the pharmaceutical industry for their ability to produce high concentrations of antibodies and their resemblance to...
Chinese hamster ovary (CHO) cells are popular in the pharmaceutical industry for their ability to produce high concentrations of antibodies and their resemblance to human cells in terms of protein glycosylation patterns. Current data indicate the relevance of CHO cells in the biopharmaceutical industry, with a high number of product commendations and a significant market share for monoclonal antibodies. To enhance the production capabilities of CHO cells, a deep understanding of their cellular and molecular composition is crucial. Genome sequencing and proteomic analysis have provided valuable insights into the impact of the bioprocessing conditions, productivity, and product quality. In our investigation, we conducted a comparative analysis of proteomic profiles in high and low monoclonal antibody-producing cell lines and studied the impact of tunicamycin (TM)-induced endoplasmic reticulum (ER) stress. We examined the expression levels of different proteins including unfolded protein response (UPR) target genes by using label-free quantification techniques for protein abundance. Our results show the upregulation of proteins associated with protein folding mechanisms in low producer vs. high producer cell line suggesting a form of ER stress related to specific protein production. Further, Hspa9 and Dnaja3 are notable candidates activated by the mitochondria UPR and play important roles in protein folding processes in mitochondria. We identified significant upregulation of Nedd8 and Lgmn proteins in similar levels which may contribute to UPR stress. Interestingly, the downregulation of Hspa5/Bip and Pdia4 in response to tunicamycin treatment suggests a low-level UPR activation. KEY POINTS: • Proteome profiling of recombinant CHO cells under mild TM treatment. • Identified protein clusters are associated with the unfolded protein response (UPR). • The compared cell lines revealed noticeable disparities in protein expression levels.
Topics: CHO Cells; Cricetulus; Tunicamycin; Animals; Antibodies, Monoclonal; Proteomics; Endoplasmic Reticulum Stress; Unfolded Protein Response; Proteome; Cricetinae
PubMed: 38896138
DOI: 10.1007/s00253-024-13223-1 -
Aging Cell Jun 2024The transcription factor HSF-1 (heat shock factor 1) acts as a master regulator of heat shock response in eukaryotic cells to maintain cellular proteostasis. The protein...
Age-dependent heat shock hormesis to HSF-1 deficiency suggests a compensatory mechanism mediated by the unfolded protein response and innate immunity in young Caenorhabditis elegans.
The transcription factor HSF-1 (heat shock factor 1) acts as a master regulator of heat shock response in eukaryotic cells to maintain cellular proteostasis. The protein has a protective role in preventing cells from undergoing ageing, and neurodegeneration, and also mediates tumorigenesis. Thus, modulating HSF-1 activity in humans has a promising therapeutic potential for treating these pathologies. Loss of HSF-1 function is usually associated with impaired stress tolerance. Contrary to this conventional knowledge, we show here that inactivation of HSF-1 in the nematode Caenorhabditis elegans results in increased thermotolerance at young adult stages, whereas HSF-1 deficiency in animals passing early adult stages indeed leads to decreased thermotolerance, as compared to wild-type. Furthermore, a gene expression analysis supports that in young adults, distinct cellular stress response and immunity-related signaling pathways become induced upon HSF-1 deficiency. We also demonstrate that increased tolerance to proteotoxic stress in HSF-1-depleted young worms requires the activity of the unfolded protein response of the endoplasmic reticulum and the SKN-1/Nrf2-mediated oxidative stress response pathway, as well as an innate immunity-related pathway, suggesting a mutual compensatory interaction between HSF-1 and these conserved stress response systems. A similar compensatory molecular network is likely to also operate in higher animal taxa, raising the possibility of an unexpected outcome when HSF-1 activity is manipulated in humans.
PubMed: 38895933
DOI: 10.1111/acel.14246 -
Frontiers in Plant Science 2024Plant viruses cause substantial losses in crop yield and quality; therefore, devising new, robust strategies to counter viral infections has important implications for...
Plant viruses cause substantial losses in crop yield and quality; therefore, devising new, robust strategies to counter viral infections has important implications for agriculture. Virus inhibitory protein endoplasmic reticulum-associated interferon-inducible (Viperin) proteins are conserved antiviral proteins. Here, we identified a set of Viperin and Viperin-like proteins from multiple species and tested whether they could interfere with RNA viruses . Our data from transient and stable overexpression of these proteins in reveal varying levels of interference against the RNA viruses tobacco mosaic virus (TMV), turnip mosaic virus (TuMV), and potato virus x (PVX). Harnessing the potential of these proteins represents a novel avenue in plant antiviral approaches, offering a broader and more effective spectrum for application in plant biotechnology and agriculture. Identifying these proteins opens new avenues for engineering a broad range of resistance to protect crop plants against viral pathogens.
PubMed: 38895613
DOI: 10.3389/fpls.2024.1385169 -
BioRxiv : the Preprint Server For... Jun 2024Exposure to loud noise is a common cause of acquired hearing loss. Disruption of subcellular calcium homeostasis and downstream stress pathways in the endoplasmic...
Exposure to loud noise is a common cause of acquired hearing loss. Disruption of subcellular calcium homeostasis and downstream stress pathways in the endoplasmic reticulum and mitochondria, including the unfolded protein response, have been implicated in the pathophysiology of noise-induced hearing loss. However, studies on the association between calcium homeostasis and stress pathways has been limited due to limited ability to measure calcium dynamics in mature-hearing, noise-exposed mice. We used a genetically encoded calcium indicator mouse model in which GcAMP is expressed specifically in hair cells or supporting cells under control of Myo15Cre or Sox2Cre, respectively. We performed live calcium imaging and UPR gene expression analysis in 8-week-old mice exposed to levels of noise that cause cochlear synaptopathy (98 db SPL) or permanent hearing loss (106 dB SPL). UPR activation occurred immediately after noise exposure and was noise dose-dependent, with the pro-apoptotic pathway upregulated only after 106 dB noise exposure. Spontaneous calcium transients in hair cells and intercellular calcium waves in supporting cells, which are present in neonatal cochleae, were quiescent in mature-hearing cochleae, but re-activated upon noise exposure. 106 dB noise exposure was associated with more persistent and expansive ICS wave activity. These findings demonstrate a strong and dose-dependent association between noise exposure, UPR activation, and changes in calcium homeostasis in hair cells and supporting cells, suggesting that targeting these pathways may be effective to develop treatments for noise-induced hearing loss.
PubMed: 38895437
DOI: 10.1101/2024.06.05.597671 -
BioRxiv : the Preprint Server For... Jun 2024Local protein synthesis in axons and dendrites underpins synaptic plasticity. However, the composition of the protein synthesis machinery in distal neuronal processes...
Local protein synthesis in axons and dendrites underpins synaptic plasticity. However, the composition of the protein synthesis machinery in distal neuronal processes and the mechanisms for its activity-driven deployment to local translation sites remain unclear. Here, we employed cryo-electron tomography, volume electron microscopy, and live-cell imaging to identify Ribosome-Associated Vesicles (RAVs) as a dynamic platform for moving ribosomes to distal processes. Stimulation via chemically-induced long-term potentiation causes RAV accumulation in distal sites to drive local translation. We also demonstrate activity-driven changes in RAV generation and dynamics , identifying tubular ER shaping proteins in RAV biogenesis. Together, our work identifies a mechanism for ribosomal delivery to distal sites in neurons to promote activity-dependent local translation.
PubMed: 38895376
DOI: 10.1101/2024.06.07.598007