As a canonical lymphocyte antigen-6/urokinase-type plasminogen activator receptor Ly6/uPAR family protein, lymphocyte antigen 6 complex, locus E (LY6E), plays important roles in immunological ...regulation, T cell physiology, and oncogenesis. Emerging evidence indicates that LY6E is also involved in the modulation of viral infection. Consequently, viral infection and associated pathogenesis have been associated with altered LY6E gene expression. The interaction between viruses and the host immune system has offered insights into the biology of LY6E. In this review, we summarize the current knowledge of LY6E in the context of viral infection, particularly viral entry.
Current efforts to develop Zika virus (ZIKV) subunit vaccines have been focused on pre-membrane (prM) and envelope (E) proteins, but the role of NS1 in ZIKV-specific immune response and protection is ...poorly understood. Here, we develop an attenuated recombinant vesicular stomatitis virus (rVSV)-based vaccine expressing ZIKV prM-E-NS1 as a polyprotein. This vectored vaccine candidate is attenuated in mice, where a single immunization induces ZIKV-specific antibody and T cell immune responses that provide protection against ZIKV challenge. Co-expression of prM, E, and NS1 induces significantly higher levels of Th2 and Th17 cytokine responses than prM-E. In addition, NS1 alone is capable of conferring partial protection against ZIKV infection in mice even though it does not induce neutralizing antibodies. These results demonstrate that attenuated rVSV co-expressing prM, E, and NS1 is a promising vaccine candidate for protection against ZIKV infection and highlights an important role for NS1 in ZIKV-specific cellular immune responses.
Despite more effective chemotherapy combined with limb-salvage surgery for the osteosarcoma treatment, survival rates for osteosarcoma patients have stagnated over the past three decades due to the ...poor prognosis. Osteosarcoma cancer stem cells (OSCs) are responsible for the growth and metastasis of osteosarcoma. The existence of OSCs offers a theoretical explanation for therapeutic failures including tumor recurrence, metastasis, and drug resistance. Understanding the pathways that regulate properties of OSCs may shed light on mechanisms that lead to osteosarcoma and suggest better modes of treatment. In this study, we showed that the expression level of Kruppel-like factor 4 (KLF4) is highly associated with human osteosarcoma cancer stemness. KLF4-overexpressed osteosarcoma cells displayed characteristics of OSCs: increased sphere-forming potential, enhanced levels of stemness-associated genes, great chemoresistance to adriamycin and CDDP, as well as more metastasis potential. Inversely, KLF4 knockdown could reduce colony formation in vitro and inhibit tumorigenesis in vivo, supporting an oncogenic role for KLF4 in osteosarcoma pathogenesis. Furthermore, KLF4 was shown to activate the p38 MAPK signaling pathway to promote cancer stemness. Altogether, our studies uncover an essential role for KLF4 in regulation of OSCs and identify KLF4-p38 MAPK axis as a potential therapeutic target for osteosarcoma treatment.
The accumulation of lipid peroxides is recognized as a determinant of the occurrence of ferroptosis. However, the sensors and amplifying process of lipid peroxidation linked to ferroptosis remain ...obscure. Here we identify PKCβII as a critical contributor of ferroptosis through independent genome-wide CRISPR-Cas9 and kinase inhibitor library screening. Our results show that PKCβII senses the initial lipid peroxides and amplifies lipid peroxidation linked to ferroptosis through phosphorylation and activation of ACSL4. Lipidomics analysis shows that activated ACSL4 catalyses polyunsaturated fatty acid-containing lipid biosynthesis and promotes the accumulation of lipid peroxidation products, leading to ferroptosis. Attenuation of the PKCβII-ACSL4 pathway effectively blocks ferroptosis in vitro and impairs ferroptosis-associated cancer immunotherapy in vivo. Our results identify PKCβII as a sensor of lipid peroxidation, and the lipid peroxidation-PKCβII-ACSL4 positive-feedback axis may provide potential targets for ferroptosis-associated disease treatment.
Background
The prognostic significance of hyperperfusion after reperfusion therapy in patients with acute ischemic stroke (AIS) remains controversial.
Purpose
To investigate the clinical factors ...associated with hyperperfusion, and the 90‐day prognostic value of hyperperfusion after mechanical thrombectomy in AIS patients.
Study Type
Retrospective.
Population/Subjects
Fifty‐four AIS patients who underwent mechanical thrombectomy.
Field Strength/Sequence
Time‐of‐flight MR angiography, pulsed arterial spin labeling (ASL), diffusion‐weighted imaging (DWI), and susceptibility‐weighted imaging were performed at 3.0T within 1 week after thrombectomy.
Assessment
Clinical factors including demographics, risk factors, stroke and treatment characteristics were collected and assessed. Hyperperfusion on ASL was defined as a focal increased cerebral blood flow on the affected side ≥130% of its mirror counterpart. Good clinical outcome at 90 days was defined as modified Rankin Scale score of 0–2.
Statistical Tests
The interrater agreement was assessed using Cohen's kappa or the intraclass correlation coefficient. The relationship between hyperperfusion and clinical factors were analyzed by appropriate univariate statistics. Predictors of 90‐day functional outcome were assessed by univariate analyses followed by multivariate logistic regression analysis and receiver‐operating‐characteristic curves.
Results
Thirty‐six (66.7%) patients developed hyperperfusion on ASL after thrombectomy. Hyperperfusion was significantly correlated with successful recanalization (P < 0.05) and improvement of National Institutes of Health Stroke Scale scores at 24 hours (NIHSS24h) (P < 0.05). A higher incidence of hemorrhage transformation was observed in patients with hyperperfusion than those without (63.9% vs. 50.0%), but no significant difference was found (P = 0.327). NIHSS24h (odds ratio OR, 0.75, 95% confidence interval CI 0.62–0.91, P < 0.05), lesion volume on diffusion‐weighted imaging (OR, 0.97, 95% CI 0.95–1.00, P < 0.05), and hyperperfusion on ASL (OR, 9.8, 95% CI 1.7–55.3, P < 0.05) were independent variables for predicting good functional outcomes.
Data Conclusion
Hyperperfusion on ASL correlated with successful recanalization and may be an independent prognostic marker for good neurological outcomes at 90 days in AIS patients after mechanical thrombectomy.
Level of Evidence
4
Technical Efficacy Stage
2
Overexpression of ANXA1 and EphA2 has been linked to various cancers and both proteins have attracted considerable attention for the development of new anticancer drugs. Here we report that ANXA1 ...competes with Cbl for binding EphA2 and increases its stability by inhibiting Cbl-mediated EphA2 ubiquitination and degradation in nasopharyngeal carcinoma (NPC). Binding of ANXA1 to EphA2 promoted NPC cell growth and metastasis
and
by elevating EphA2 levels and increasing activity of EphA2 oncogenic signaling (pS897-EphA2). Expression of ANXA1 and EphA2 was positively correlated and both were significantly higher in NPC tissues than in the normal nasopharyngeal epithelial tissues. Patients with high expression of both proteins presented poorer disease-free survival and overall survival relative to patients with high expression of one protein alone. Furthermore, amino acid residues 20-30aa and 28-30aa of the ANXA1 N-terminus bound EphA2. An 11 amino acid-long ANXA1-derived peptide (EYVQTVKSSKG) was developed on the basis of this N-terminal region, which disrupted the connection of ANXA1 with EphA2, successfully downregulating EphA2 expression and dramatically suppressing NPC cell oncogenicity
and in mice. These findings suggest that ANXA1 promotes NPC growth and metastasis via binding and stabilization of EphA2 and present a strategy for targeting EphA2 degradation and treating NPC with a peptide. This therapeutic strategy may also be extended to other cancers with high expression of both proteins. SIGNIFICANCE: These findings show that EphA2 is a potential target for NPC therapeutics and an ANXA1-derived peptide suppresses NPC growth and metastasis. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/20/4386/F1.large.jpg.
LY6E is a glycosylphosphatidylinositol-anchored, IFN-inducible protein that regulates T lymphocytes proliferation, differentiation, and development. Single-nucleotide polymorphism rs2572886 in the ...LY6 family protein locus has been shown to associate with accelerated progression to AIDS. In this study, we show that LY6E promotes HIV, type 1 (HIV-1) infection by enhancing viral entry and gene expression. Knockdown of LY6E in human peripheral blood mononuclear, SupT1, and THP-1 cells diminishes HIV-1 replication. Virion-cell and cell-cell fusion experiments revealed that LY6E promotes membrane fusion of the viral entry step. Interestingly, we find that LTR-driven HIV-1 gene expression is also enhanced by LY6E, suggesting additional roles of LY6E in HIV-1 replication. HIV-1 infection induces LY6E expression in human peripheral blood mononuclear cells, concomitant with increased production of type I IFN and some classical IFN-stimulated genes. Altogether, our results demonstrate that IFN-inducible LY6E promotes HIV-1 entry and replication and highlight a positive regulatory role of IFN-induced proteins in HIV-1 infection. Our work emphasizes the complexity of IFN-mediated signaling in HIV-host interaction and AIDS pathogenesis.
Lymphocyte antigen 6E (LY6E) is a GPI-anchored, interferon-inducible protein that has been shown to modulate viral infection in a cell type-dependent manner. Our recent work showed that LY6E promotes ...HIV-1 infection in some high-CD4-expressing cells, including human peripheral blood mononuclear cells (PBMCs) and the SupT1 cell line. In this work, we provide evidence that LY6E inhibits HIV-1 entry and spread in low-CD4-expressing Jurkat cells and human monocyte-derived macrophages (MDMs) through downregulation of the viral receptor CD4. We found that knockdown of LY6E in Jurkat cells and MDMs increases HIV-1 infection, yet overexpression of LY6E in Jurkat cells inhibits HIV-1 entry and replication. LY6E was found to be colocalized with CD4 on the plasma membrane of Jurkat cells and MDMs and enhances CD4 internalization. We artificially manipulated the CD4 level in Jurkat and SupT1 cells and found that overexpression of CD4 in Jurkat cells overcomes the inhibitory effect of LY6E; conversely, blocking the function of CD4 in SupT1 with a neutralizing antibody eliminates the enhancement of LY6E on HIV-1 entry. The CD4-dependent inhibitory phenotype of LY6E in low-CD4-expressing human MDMs can be recapitulated for a panel of transmitted founder viruses and laboratory-adapted HIV-1 strains. Given that HIV-1 can target low-CD4-expressing cells during acute infection yet replicates efficiently in high-CD4-expressing T cells at the late stage of disease, our observation that LY6E differentially modulates HIV-1 replication in a CD4-dependent manner has implications for understanding the complex roles of interferon (IFN)-induced proteins in AIDS pathogenesis.
The role of IFN-induced genes (ISGs) in viral infection remains incompletely understood. While most ISGs are antiviral, some ISGs have been shown to promote viral infection, including HIV-1 infection. We previously showed that IFN-inducible LY6E protein promotes HIV-1 infection in human PMBCs and high-CD4-expressing SupT1 cells. Here we found that LY6E inhibits HIV-1 entry and replication in low-CD4-expressing MDMs and Jurkat cells. Mechanistically, we demonstrated that LY6E downregulates the cell surface receptor CD4, thus impairing the virus binding to target cells. This is in contrast to the situation of high-CD4-expressing cells, where LY6E predominantly promotes viral membrane fusion. The opposing role of IFN-inducible LY6E in modulating HIV-1 infection highlights the complex roles of ISGs in viral infection and viral pathogenesis.
While cytoplasmic aggregation of TDP-43 is a pathological hallmark of amyotrophic lateral sclerosis and frontotemporal dementia, how aggregates form and what drives its nuclear clearance have not ...been determined. Here we show that TDP-43 at its endogenous level undergoes liquid-liquid phase separation (LLPS) within nuclei in multiple cell types. Increased concentration of TDP-43 in the cytoplasm or transient exposure to sonicated amyloid-like fibrils is shown to provoke long-lived liquid droplets of cytosolic TDP-43 whose assembly and maintenance are independent of conventional stress granules. Cytosolic liquid droplets of TDP-43 accumulate phosphorylated TDP-43 and rapidly convert into gels/solids in response to transient, arsenite-mediated stress. Cytoplasmic TDP-43 droplets slowly recruit importin-α and Nup62 and induce mislocalization of RanGap1, Ran, and Nup107, thereby provoking inhibition of nucleocytoplasmic transport, clearance of nuclear TDP-43, and cell death. These findings identify a neuronal cell death mechanism that can be initiated by transient-stress-induced cytosolic de-mixing of TDP-43.
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•Transient stress induces long-lasting phase separation of cytoplasmic TDP-43•Formation/maintenance of phase separated TDP-43 is independent of stress granules•Phase-separated TDP-43 inhibits nuclear transport by de-mixing importin-α and Nup62•Cytoplasmic TDP-43 de-mixing depletes nuclear TDP-43 and induces cell death
TDP-43 aggregation is the major hallmark of multiple neurodegenerative diseases, including ALS and FTD. Gasset-Rosa et al. demonstrate that transient stress induces long-lasting cytoplasmic TDP-43 de-mixing independent of stress granules, driving nuclear import defects, nuclear TDP-43 clearance, and cell death.
This study aimed to evaluate the feasibility of intraarterial (IA) delivery and in vivo MR imaging of superparamagnetic iron oxide (SPIO)-labeled mesenchymal stem cells (MSCs) in a canine stroke ...model.
MSCs harvested from beagles' bone marrow were labeled with home-synthesized SPIO. Adult beagle dogs (n = 12) were subjected to left proximal middle cerebral artery (MCA) occlusion by autologous thrombus, followed by two-hour left internal carotid artery (ICA) occlusion with 5 French vertebral catheter. One week later, dogs were classified as three groups before transplantation: group A: complete MCA recanalization, group B: incomplete MCA recanalization, group C: no MCA recanalization. 3×10(6) labeled-MSCs were delivered through left ICA. Series in vivo MRI images were obtained before cell grafting, one and 24 hours after transplantation and weekly thereafter until four weeks. MRI findings were compared with histological studies at the time point of 24 hours and four weeks.
Home-synthesized SPIO was useful to label MSCs without cell viability compromise. MSCs scattered widely in the left cerebral hemisphere in group A, while fewer grafted cells were observed in group B and no cell was detected in group C at one hour after transplantation. A larger infarction on the day of cell transplantation was associated with more grafted cells in the brain. Grafted MSCs could be tracked effectively by MRI within four weeks and were found in peri-infarction area by Prussian blue staining.
It is feasible of IA MSCs transplantation in a canine stroke model. Both the ipsilateral MCA condition and infarction volume before transplantation may affect the amount of grafted cells in target brain. In vivo MR imaging is useful for tracking IA delivered MSCs after SPIO labeling.
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