Cell Communication and Signaling最新文献

Background: Severe cases of COVID-19 are characterized by an excessive presence of neutrophils. Neutrophil extracellular traps (NETs), released by activated neutrophils due to SARS-CoV-2 infection, contribute to lung epithelial cell death and are key drivers in COVID-19-associated immunothrombosis. However, the mechanism underlying NET formation in COVID-19 remain unclear.

Methods: Extracellular vesicles (EVs) were isolated from the serum of COVID-19 patients and healthy volunteers, while neutrophils were isolated from blood samples of healthy volunteers. Neutrophils were treated with EVs, and the formation of NETs was observed. To identify the components responsible for the COVID-19-EVs-induced NET formation, we analyzed the expression profiles of microRNA (miRNAs) in COVID-19-EVs. We identified eight highly expressed miRNAs in COVID-19-EVs and explored their potential roles in COVID-19-EVs-mediated NET formation. Additionally, we explored the role of miR-20b-5p in COVID-19-EVs-induced NET formation.

Results: In this study, we demonstrate that patients with COVID-19 have a higher concentration of serum EVs (COVID-19-EVs) than healthy controls (Normal-EVs). We also found that COVID-19-EVs are internalized by neutrophils to induced NET formation. Through comprehensive miRNA profiling of COVID-19-EVs versus Normal-EVs, we identified 78 differentially expressed miRNAs, with 27 of these being upregulated and 51 being downregulated. Subsequently, we discovered that COVID-19-EVs that were highly abundant with certain miRNAs promote NET formation. Specifically, miR-20b-5p was found to be the strongest inducer of NET formation of the identified miRNAs. Inhibition of miR-20b-5p resulted in a significant decrease in COVID-19-EVs-mediated induction of NET formation.

Conclusion: Herein, we reveal a previously unknown role of COVID-19-EVs in NET formation, which contributes to COVID-19 progression. This study suggests that miR-20b-5p may serve as a potential therapeutic target for COVID-19 treatment.

Background: Pharmacological targeting of Hedgehog (HH)/GLI has proven effective for certain blood, brain and skin cancers including basal cell carcinoma (BCC). However, limited response rates and the development of drug resistance call for improved anti-HH therapies that take synergistic crosstalk mechanisms and immune evasion strategies into account. In previous work, we demonstrated that cooperation of HH/GLI and Interleukin 6 (IL6)/STAT3 signaling drives BCC growth. Whether synergistic HH-IL6 signaling promotes BCC via the activation of immune evasion mechanisms remained unclear.

Methods: HH-IL6 regulated immunosuppressive genes such as indoleamine 2,3-dioxygenase 1 (IDO1) were identified by gene expression profiling. IDO1 expression was evaluated in human BCC and melanoma models by qPCR and Western blot analyses. The cis-regulatory region of IDO1 was interrogated for HH-IL6-regulated GLI and STAT transcription factor binding and epigenetic modifications by targeted chromatin-immunoprecipitation and bisulfite pyrosequencing. Functional analyses of the immunosuppressive effects of IDO1 involved HPLC-MS measurements of its metabolites and the assessment of T cell proliferation via flow cytometry. Bioinformatic analyses of GLI-STAT cooperation were conducted on published bulk and single-cell RNA-seq data of human BCC and melanoma patients.

Results: We identified IDO1 as a target gene of cooperative GLI-STAT activity in BCC and melanoma. GLI1 and STAT3 transcription factors synergistically enhanced IDO1 expression by jointly binding to the cis-regulatory region of IDO1 and by increasing active chromatin marks at the histone level. In human melanoma cells, inhibition of GLI1 expression prevented the induction of IDO1 expression in response to IL6/STAT3 and IFNγ/STAT1 signaling. Pharmacological targeting of HH/GLI signaling reduced IDO1 expression, resulting in decreased production of the immunosuppressive metabolite kynurenine. Further, inhibition of GLI1 enhanced the efficacy of the selective IDO1 inhibitor epacadostat and rescued T cell proliferation by attenuating IDO1/kynurenine-mediated immunosuppression. Elevated expression of IDO1 correlated with active HH/GLI and JAK/STAT signaling in skin cancer patients supporting the clinical relevance of the mechanistic data presented.

Conclusions: These results identify the immunosuppressive IDO1-kynurenine pathway as a novel pro-tumorigenic target of oncogenic GLI and STAT1/STAT3 cooperation. Our data suggest simultaneous pharmacological targeting of these signaling axes as rational combination therapy in melanoma and non-melanoma skin cancers.

Background: Adenosine A_2A receptor (A_2AR) antagonists have been consistently demonstrated to protect against multiple sclerosis (MS) pathology, but A_2AR knockout (A_2AR^-/-) mice exhibit exacerbated immune injury, raising concerns regarding the use of A_2AR antagonists for MS treatment. Here, we revealed the critical involvement of A_2AR-mediated interactions between Th1⁺ T cells and the choroid plexus (ChP) epithelium in the pathology of experimental autoimmune encephalomyelitis (EAE).

Methods: We assessed the effects of A_2AR knockout on ChP gateway activity and the interferon gamma (IFN-γ)-secreting capacity of Th1⁺ T cells in an EAE model by immunofluorescence, qPCR and flow cytometry (FCM). We also investigated the effects of A_2AR-mediated interactions between Th1⁺ T cells and the ChP epithelium on ChP gateway activity in vivo via intracerebroventricular (ICV) injection of Th1⁺ T cells and in vitro via coculture of ChP epithelial cells and splenic Th1⁺ T cells. We further knocked down IFN-γ receptor 1 (IFNGR1) specifically in the ChP of A_2AR^-/- mice via ICV injection of AAV2/5-shRNA (IFNGR1) to disrupt the interactions between Th1⁺ T cells and the ChP epithelium and thus assess the roles of these interactions in the development of EAE pathology.

Results: A_2AR knockout disrupted the ChP barrier and increased T-cell infiltration across the ChP in EAE model mice. Coculture of splenic Th1⁺ T cells and ChP epithelial cells revealed that A_2AR knockout in ChP epithelial cells strengthened the ChP barrier and attenuated T-cell migration, whereas A_2AR knockout in Th1⁺ T cells increased the accumulation of Th1⁺ T cells in the ChP via the secretion of IFN-γ. Consistent with the coculture results, ICV injection of activated splenic Th1⁺ T cells from A_2AR^-/- mice increased the accumulation of T cells in the ChP to a greater extent than did injection of Th1⁺ T cells from A_2AR^+/+ mice. This effect was due to the increased secretion of IFN-γ in A_2AR^-/- mice compared with A_2AR^+/+ mice. Finally, ChP-specific knockdown of IFNGR1 attenuated A_2AR knockout-induced T-cell infiltration, brain inflammation and EAE pathology.

Conclusion: A_2AR-mediated interactions between Th1⁺ T cells and the ChP epithelium via the secretion of IFN-γ from CD4⁺ T cells and the binding IFN-γ to IFNGR1 in the ChP epithelium control immune cell invasion and the development of EAE pathology in A_2AR^-/- mice.

Background: Glycosylation is an important posttranslational modification of proteins and in most cases indispensable for proper protein function. Like most soluble proteins, IgA, the second most prevalent antibody in human serum, contains several N- and O-glycosylation sites. While for IgG the impact of Fc glycosylation on effector functions and inflammatory potential has been studied intensively, only little is known for IgA. In addition, only glimpses exist regarding the regulation of IgA glycosylation. We have previously shown that IgA1 and IgA2 differ functionally and also show differences in their glycosylation pattern. The more pro-inflammatory IgA2 which is linked to autoimmune diseases displays decreased sialylation, galactosylation, fucosylation and bisection as compared to IgA1. In the present study, we aimed to investigate these differences in glycosylation in detail and to explore the mechanisms underlying them.

Methods: IgA1 and IgA2 was isolated from serum of 12 healthy donors. Site specific glycosylation was analyzed by mass spectrometry. In addition, human bone marrow plasma cells were investigated using single cell mRNA sequencing, flow cytometry and ELISpot.

Results: We found that certain glycoforms greatly differ in their abundance between IgA1 and IgA2 while others are equally abundant. Overall, the IgA2 glycans displayed a more immature phenotype with a higher prevalence of oligomannose and fewer fully processed glycans. Of note, these differences can't be explained by differences in the glycosylation enzyme machinery as mRNA sequencing and flow cytometry analysis showed equal enzyme expression in IgA1 and IgA2 producing plasma cells. ELISpot analysis suggested a slightly increased antibody production rate in IgA2 producing plasma cells which might contribute to its lower glycan processing rates. But this difference was only minor, suggesting that further factors such as steric accessibility determine glycan processing. This is supported by the fact that glycans at different positions on the same IgA chain differ dramatically in fucosylation, sialylation and bisection.

Conclusion: In summary, our detailed overview of IgA1 and IgA2 glycosylation shows a class, subclass, and site-specific glycosylation fingerprint, most likely due to structural differences of the protein backbones.

Background: The neuroretinal vascular system is comprised of three interconnected layers. The initial superficial vascular plexus formation is guided by astrocytes around birth in mice. The formation of the deep and intermediate vascular plexuses occurs in the second postnatal week and is driven by Müller-cell-derived angiogenic signaling. Previously, we reported that microglia play an important role in regulating astrocyte density during superficial vascular plexus formation. Here, we investigated the role of microglia in regulating Müller-cell-dependent inner retinal vascular development.

Methodology: In this study, we depleted microglia during retinal development using Csf1R antagonist (PLX5622). We characterized the developmental progression of inner retinal vascular growth, effect of microglial depletion on inner retinal vascular growth and Müller cell marker expressions by immunostaining. Differential expressions of genes in the control and microglia depleted groups were analyzed by mRNA-seq and qPCR. Unpaired t-test was performed to determine the statistical differences between groups.

Results: This study show that microglia interact with Müller cells and the growing inner retinal vasculature. Depletion of microglia resulted in reduced inner retinal vascular layers densities and decreased Vegfa isoforms transcript levels. RNA-seq analysis further revealed that microglial depletion significantly reduced specific Müller cell maturation markers including glutamine synthetase, responsible for glutamine biosynthesis, necessary for angiogenesis.

Conclusions: Our study reveals an important role for microglia in facilitating inner retinal angiogenesis and Müller cell maturation.

Membrane contact sites (MCS) are specialized regions where organelles are closely interconnected through membrane structures, facilitating the transfer and exchange of ions, lipids, and other molecules. This proximity enables a synergistic regulation of cellular homeostasis and functions. The formation and maintenance of these contact sites are governed by specific proteins that bring organelle membranes into close apposition, thereby enabling functional crosstalk between cellular compartments. In eukaryotic cells, lipids are primarily synthesized and metabolized within distinct organelles and must be transported through MCS to ensure proper cellular function. Consequently, MCS act as pivotal platforms for lipid synthesis and trafficking, particularly in cancer cells and immune cells within the tumor microenvironment, where dynamic alterations are critical for maintaining lipid homeostasis. This article provides a comprehensive analysis of how these cells exploit membrane contact sites to modulate lipid synthesis, metabolism, and transport, with a specific focus on how MCS-mediated lipid dynamics influence tumor progression. We also examine the differences in MCS and associated molecules across various cancer types, exploring novel therapeutic strategies targeting MCS-related lipid metabolism for the development of anticancer drugs, while also addressing the challenges involved.

Background: Transfer RNA-derived small RNAs (tsRNAs), including tRNA-derived fragments (tRFs) and tRNA halves (tiRNAs), constitute a novel class of small noncoding RNAs (sncRNAs). tsRNAs have been linked to tumorigenesis and the progression of carcinogenesis; however, the precise molecular mechanism through which tRFs act in gastric cancer (GC) remains unknown.

Methods: tRF-Tyr is a potential GC tumor suppressor that was identified through high-throughput sequencing technology. The expression and subcellular localization of tRF-Tyr in GC were detected by via qRT‒PCR and FISH. RNA pull-down, mass spectrometry, RNA immunoprecipitation (RIP), dual-luciferase reporter and rescue assays were performed to explore the regulatory mechanisms through which tRF-Tyr acts in GC.

Results: tRF-Tyr was significantly downregulated and the downregulation of its mainly concentrated in the nuclei of GC cells. Functionally, tRF-Tyr inhibited the proliferation, invasiveness and migration of GC cells and promoted GC cells apoptosis in vitro; meanwhile, tRF-Tyr inhibited tumor growth in vivo. Mechanistically, tRF-Tyr bound directly to the hnRNPD protein and competitively inhibited the binding of hnRNPD to the c-Myc 3'UTR, thereby, regulating the c-Myc/Bcl2/Bax pathway and ultimately inhibiting the progression of GC.

Conclusions: This study focused on a novel GC suppressor, tRF-Tyr, and revealed a previously undiscovered mechanism that tRF-Tyr inhibits tumor progression by targeting hnRNPD. These findings provide new insight into the involvement of tRFs in GC and suggest a novel target for GC treatment.

Sepsis remains the leading cause of death in intensive care units. Despite newer antimicrobial and supportive therapies, specific treatments are still lacking. Neutrophils are pivotal components of the effector phase of the host immune defense against pathogens and play a crucial role in the control of infections under normal circumstances. In addition to its anti-infective effects, the dysregulation and overactivation of neutrophils may lead to severe inflammation or tissue damage and are potential mechanisms for poor prognosis in sepsis. This review focuses on recent advancements in the understanding of the functional status of neutrophils across various pathological stages of sepsis to explore the mechanisms by which neutrophils participate in sepsis progression and provide insights for the treatment of sepsis by targeting neutrophils.

Background: Tumor dissemination is a life-threatening event which confers to most cancer-related deaths with limited effective therapeutic option. TNFα-induced protein 2 (TNFAIP2) reveals pro-metastasis potential in several cancers. However, its definite role and underlying mechanism in oral squamous cell carcinoma (OSCC) is largely unknown.

Methods: The impact of TNFAIP2 on tumor metastasis was assessed based on the conditional knockout mouse with 4-nitroquinoline-1-oxide (4NQO) induced OSCC model through feature and immunohistochemistry analysis. To explore the specific mechanism, enrichment analysis and co-immunoprecipitation were applied. Meanwhile, the nano-hydroxyapatite (nHAp) and poly-L-lysine (PLL) based RNA interference delivery system was designed to restrict tumor dissemination.

Results: The conditional knockout Tnfaip2 in epithelium reduced tumor initiation rate, differentiation degree and cervical lymph node metastasis (LNM) in mouse exposed to 4NQO. Enrichment analysis suggested nuclear factor-kappa B (NF-κB) signaling was associated with these effects. Western blot proved that TNFAIP2 prevented the ubiquitin proteasome degradation of inhibitor of kappa light polypeptide gene enhancer in B-cells, kinase beta (IKKβ), a classical transcriptional activator protein in NF-κB signaling. Mechanistically, TNFAIP2 was demonstrated to competitively interact with kelch-like ECH-associated protein 1 (KEAP1) to avoid IKKβ from ubiquitination at K63 and proteasomal degradation subsequently, which finally sustained NF-κB signaling and facilitated tumor metastasis by enhancing epithelial-mesenchymal transition (EMT) and lymphangiogenesis. Notably, the synthetic small interfering RNA delivery systems nHAp@PLL-siTnfaip2 showed significant effect in attenuating tumor progression of OSCC mouse.

Conclusion: Above results showed TNFAIP2 promoted EMT and lymphangiogenesis of OSCC by regulating NF-κB signaling, a mechanism that was dependent on the interaction with KEAP1 competitively. The nHAp based TNFAIP2 interference might serve as a novel therapeutic in limiting OSCC metastasis.

Stress granules (SGs) are conserved messenger ribonucleoprotein (mRNP) granules that form through rapid coalescence in the cytoplasm of eukaryotic cells under stressful environments. These dynamic membrane-free organelles can respond to a variety of both intracellular and extracellular stressors. Studies have shown that stress conditions such as heat stress, arsenite exposure, and hypoxic stress can induce SGs formation. The formation of SGs helps mitigates the effects of environmental stimuli on cells, protects them from damage, and promotes cell survival. This paper focuses on the biogenesis of SGs and summarizes the role in regulating environmental stress-induced male reproductive disorders, with the aim of exploring SGs as a potential means of mitigating male reproduction disorders. Numerous studies have demonstrated that the detrimental effects of environmental stress on germ cells can be effectively suppressed by regulating the formation and timely disassembly of SGs. Therefore, regulating the phosphorylation of eIF2α and the assembly and disassembly of SGs could offer a promising therapeutic strategy to alleviate the impacts of environmental stress on male reproduction health.