Disulfide reduction in the endocytic pathway: immunological functions of gamma-interferon-inducible lysosomal thiol reductase

Enhancing the cytotoxicity of immunotoxins by facilitating their dissociation from target receptors under the reducing conditions of the endocytic pathway

Immunotoxins (ITs) are recombinant chimeric proteins that combine a protein toxin with a targeting moiety to facilitate the selective delivery of the toxin to cancer cells. Here, we present a novel strategy to enhance the cytosolic access of ITs by promoting their dissociation from target receptors under the reducing conditions of the endocytic pathway. We engineered monobodySS, a human fibronectin type III domain-based monobody with disulfide bond (SS)-containing paratopes, targeting receptors such as EGFR, EpCAM, Her2, and FAP. MonobodySS exhibited SS-dependent target receptor binding with a significant reduction in binding under reducing conditions. We then created monobodySS-based ITs carrying a 25 kDa fragment of Pseudomonas exotoxin A (PE25), termed monobodySS-PE25. These ITs showed dose-dependent cytotoxicity against target receptor-expressing cancer cells and a wider therapeutic window due to higher efficacy at lower doses compared to controls with SS reduction inhibited. ERSS/28-PE25, with a KD of 28 nM for EGFR, demonstrated superior tumor-killing potency compared to ER/21-PE25, which lacks an SS bond, at equivalent and lower doses. In vivo, ERSS/28-PE25 outperformed ER/21-PE25 in suppressing tumor growth in EGFR-overexpressing xenograft mouse models. This study presents a strategy for developing solid tumor-targeting ITs using SS-containing paratopes to enhance cytosolic delivery and antitumor efficacy.

Interferon Gamma Inducible Protein 30: from biological functions to potential therapeutic target in cancers

Interferon Gamma Inducible Protein 30 (IFI30), also known as Gamma-Interferon-Inducible Lysosomal Thiol Reductase (GILT), is predominantly found in lysosomes and the cytoplasm. As the sole enzyme identified to catalyze disulfide bond reduction in the endocytic pathway, IFI30 contributes to both major histocompatibility complex (MHC) class I-restricted antigen cross-presentation and MHC class II-restricted antigen processing by decreasing the disulfide bonds of endocytosed proteins. Remarkably, emerging research has revealed that IFI30 is involved in tumorigenesis, tumor development, and the tumor immune response. Targeting IFI30 may provide new strategies for cancer therapy and improve the prognosis of patients. This review provided a comprehensive overview of the research progress on IFI30 in tumor progression, cellular redox status, autophagy, tumor immune response, and drug sensitivity, with a view to providing the theoretical basis for pharmacological intervention of IFI30 in tumor therapy, particularly in immunotherapy.

Proteomimetic Polymers Trigger Potent Antigen-Specific T Cell Responses to Limit Tumor Growth

Elicitation of effective antitumor immunity following cancer vaccination requires the selective activation of distinct effector cell populations and pathways. Here we report a therapeutic approach for generating potent T cell responses using a modular vaccination platform technology capable of inducing directed immune activation, termed the Protein-like Polymer (PLP). PLPs demonstrate increased proteolytic resistance, high uptake by antigen-presenting cells (APCs), and enhanced payload-specific T cell responses. Key design parameters, namely payload linkage chemistry, degree of polymerization, and side chain composition, were varied to optimize vaccine formulations. Linking antigens to the polymer backbone using an intracellularly cleaved disulfide bond copolymerized with a diluent amount of oligo(ethylene glycol) (OEG) resulted in the highest payload-specific potentiation of antigen immunogenicity, enhancing dendritic cell (DC) activation and antigen-specific T cell responses. Vaccination with PLPs carrying either gp100, E7, or adpgk peptides significantly increased the survival of mice inoculated with B16F10, TC-1, or MC38 tumors, respectively, without the need for adjuvants. B16F10-bearing mice immunized with gp100-carrying PLPs showed increased antitumor CD8+ T cell immunity, suppressed tumor growth, and treatment synergy when paired with two distinct stimulator of interferon gene (STING) agonists. In a human papillomavirus-associated TC-1 model, combination therapy with PLP and 2'3'-cGAMP resulted in 40% of mice completely eliminating implanted tumors while also displaying curative protection from rechallenge, consistent with conferment of lasting immunological memory. Finally, PLPs can be stored long-term in a lyophilized state and are highly tunable, underscoring the unique properties of the platform for use as generalizable cancer vaccines.

NCF4 regulates antigen presentation of cysteine peptides by intracellular oxidative response and restricts activation of autoreactive and arthritogenic T cells

Autoimmune diseases, such as rheumatoid arthritis (RA) and systemic lupus erythematous, are regulated by polymorphisms in genes contributing to the NOX2 complex. Mutations in both Ncf1 and Ncf4 affect development of arthritis in experimental models of RA, but the different regulatory pathways mediated by NOX2-derived reactive oxygen species (ROS) have not yet been clarified. Here we address the possibility that intracellular ROS, regulated by the NCF4 protein (earlier often denoted p40phox) which interacts with endosomal membranes, could play an important role in the oxidation of cysteine peptides in mononuclear phagocytic cells, thereby regulating antigen presentation and activation of arthritogenic T cells. To study the role of NCF4 we used mice with an amino acid replacing mutation (NCF4R58A), which is known to affect interaction with endosomal membranes, leading to decreased intracellular ROS production. To study the impact of NCF4 on T cell activation, we used the glucose phosphate isomerase peptide GPI325-339, which contains two cysteine residues (325-339c-c). Macrophages from mice with the NCF458A mutation efficiently presented the peptide when the two cysteines were intact and not crosslinked, leading to a strong arthritogenic T cell response. T cell priming occurred in the draining lymph nodes (LNs) within 8 days after immunization. Clodronate treatment, which depletes antigen-presenting mononuclear phagocytes, ameliorated arthritis severity, whereas treatment with FYT720, which traps activated T cells in LNs, prohibited arthritis. We conclude that NCF4-dependent intracellular ROS maintains cysteine peptides in an oxidized crosslinked state, which prevents presentation of peptides recognized by non-tolerized T cells and thereby protects against autoimmune arthritis.

IFI30 as a key regulator of PDL1 immunotherapy prognosis in breast cancer

BACKGROUND

IFI30 is a lysosomal thiol reductase involved in antigen presentation and immune regulation in various cancers, including breast cancer. Despite its known involvement, the precise mechanism, function, and relationship with the PD-L1 axis and immune response remain unclear.

METHODS

We conducted an extensive investigation into IFI30 mRNA expression in breast cancer utilizing data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases. Furthermore, we characterized IFI30 mRNA expression across various cell types using publicly available single-cell RNA sequencing datasets, and assessed protein expression through immunohistochemistry using an in-house breast cancer tissue microarray. Functional experiments were performed to elucidate the effects of IFI30 overexpression on PD-L1 expression and inhibitory efficacy in both macrophages and breast tumor cells.

RESULTS

Our study unveiled a marked upregulation of IFI30 expression in breast cancer tissues compared to their normal counterparts, with notable associations identified with tumor stage and prognosis. Additionally, IFI30 expression demonstrated significant correlations with various immune-related signaling pathways, encompassing peptide antigen binding, cytokine binding, and MHC class II presentation. Notably, breast cancer samples exhibiting high IFI30 expression in tumor cells displayed high PD-L1 expression on corresponding cells, alongside a diminished ratio of CD8 + T cell infiltration within the tumor microenvironment. Furthermore, ectopic knockdown of IFI30 in both tumor cells and macrophages resulted in a reduction of PD-L1 expression, while conversely, overexpression of IFI30 led to an increase in PD-L1 expression.

CONCLUSIONS

This study offers new insights into the involvement of IFI30 in breast cancer, elucidating its interplay with the PD-L1 axis and immune response dynamics. Our findings suggest that modulation of the IFI30-PD-L1 axis could serve as a promising strategy for regulating T cells infiltration in breast cancer thus treating breast cancer.

Molecular subtype identification and prognosis stratification based on lysosome-related genes in breast cancer

Background

Lysosomes are known to have a significant impact on the development and recurrence of breast cancer. However, the association between lysosome-related genes (LRGs) and breast cancer remains unclear. This study aims to explore the potential role of LRGs in predicting the prognosis and treatment response of breast cancer.

Methods

Breast cancer gene expression profile data and clinical information were downloaded from TCGA and GEO databases, and prognosis-related LRGs were screened for consensus clustering analysis. Lasso Cox regression analysis was used to construct risk features derived from LRGs, and immune cell infiltration, immune therapy response, drug sensitivity, and clinical pathological feature differences were evaluated for different molecular subtypes and risk groups. A nomogram based on risk features derived from LRGs was constructed and evaluated.

Results

Our study identified 176 differentially expressed LRGs that are associated with breast cancer prognosis. Based on these genes, we divided breast cancer into two molecular subtypes with significant prognostic differences. We also found significant differences in immune cell infiltration between these subtypes. Furthermore, we constructed a prognostic risk model consisting of 7 LRGs, which effectively divides breast cancer patients into high-risk and low-risk groups. Patients in the low-risk group have better prognostic characteristics, respond better to immunotherapy, and have lower sensitivity to chemotherapy drugs, indicating that the low-risk group is more likely to benefit from immunotherapy and chemotherapy. Additionally, the risk score based on LRGs is significantly correlated with immune cell infiltration, including CD8 T cells and macrophages. This risk score model, along with age, chemotherapy, clinical stage, and N stage, is an independent prognostic factor for breast cancer. Finally, the nomogram composed of these factors has excellent performance in predicting overall survival of breast cancer.

Conclusions

In conclusion, this study has constructed a novel LRG-derived breast cancer risk feature, which performs well in prognostic prediction when combined with clinical pathological features.

mosGILT controls innate immunity and germ cell development in Anopheles gambiae

Gene-edited mosquitoes lacking a gamma-interferon-inducible lysosomal thiol reductase-like protein, namely (mosGILTnull) have lower Plasmodium infection, which is linked to impaired ovarian development and immune activation. The transcriptome of mosGILTnull Anopheles gambiae was therefore compared to wild type (WT) mosquitoes by RNA-sequencing to delineate mosGILT-dependent pathways. Compared to WT mosquitoes, mosGILTnull A. gambiae demonstrated altered expression of genes related to oogenesis, 20-hydroxyecdysone synthesis, as well as immune-related genes. Serendipitously, the zero population growth gene, zpg, an essential regulator of germ cell development was found to be one of the most downregulated genes in mosGILTnull mosquitoes. These results provide a crucial missing link between two previous studies on the role of zpg and mosGILT in ovarian development. This study further demonstrates that mosGILT has the potential to serve as a target for the biological control of mosquito vectors and to influence the Plasmodium life cycle within the vector.

Functional of tongue sole (Cynoglossus semilaevis) gamma-interferon-inducible lysosomal thiol reductase with implications in innate immune reponse depend on CXXC active site

The enzyme gamma-interferon-inducible lysosomal thiol reductase (GILT) plays an important role in promoting the processing and presentation of major histocompatibility complex (MHC) class II-restricted antigens. It is also involved in MHC I-restricted antigens catalyzing disulfide bond reduction in fishes' adaptive immunity. The open reading frame of tongue sole (Cynoglossus semilaevis) GILT (tsGILT) gene is 771 bp long, encoding 257 amino acids, with a calculated molecular weight of 28.465 kDa and isoelectric point (pI) of 5.35. After induction with lipopolysaccharide, the expression of tsGILT mRNA was upregulated in spleen and kidney and recombinant tsGILT protein transferred to late endosomes and lysosomes in HeLa cells. The refolded tsGILT was capable of catalyzing the reduction of the interchain disulfide bonds against an IgG substrate depend on the active site CXXC motif at residues 75-78. The process of immune response to bacteria challenge needs GILT to catalyze the reduction of disulfide bond and unfolding native protein antigens, promoting their hydrolysis by proteases. Whether a single mutation or a double mutation of active site CXXC at residues75-78, the 3D structure of tsGILT protein has undergone major changes and lost its activity of catalyzing the reduction of the interchain disulfide bonds.

Anopheles gambiae mosGILT regulates innate immune genes and zpg expression

Gene-edited mosquitoes lacking a g amma-interferon-inducible lysosomal thiol reductase-like protein, namely ( mosGILT null ) have lower Plasmodium infection, which is linked to impaired ovarian development and immune activation. The transcriptome of mosGILT null A. gambiae was therefore compared to wild type (WT) by RNA-sequencing to delineate mosGILT-dependent pathways. Compared to WT mosquitoes, mosGILT null A. gambiae demonstrated altered expression of genes related to oogenesis, 20-hydroxyecdysone synthesis, as well as immune-related genes. Serendipitously, the zero population growth gene, zpg , an essential regulator of germ cell development was found to be one of the most downregulated genes in mosGILT null mosquitoes. These results provide the crucial missing link between two previous studies on the role of zpg and mosGILT in ovarian development. This study further demonstrates that mosGILT has the potential to serve as a target for the biological control of mosquito vectors and to influence the Plasmodium life cycle within the vector.

Ultra High-plex Spatial Proteogenomic Investigation of Giant Cell Glioblastoma Multiforme Immune Infiltrates Reveals Distinct Protein and RNA Expression Profiles

A deeper understanding of complex biological processes, including tumor development and immune response, requires ultra high-plex, spatial interrogation of multiple "omes". Here we present the development and implementation of a novel spatial proteogenomic (SPG) assay on the GeoMx Digital Spatial Profiler platform with next-generation sequencing readout that enables ultra high-plex digital quantitation of proteins (>100-plex) and RNA (whole transcriptome, >18,000-plex) from a single formalin-fixed paraffin-embedded (FFPE) sample. This study highlighted the high concordance, R > 0.85 and <15% change in sensitivity between the SPG assay and the single-analyte assays on various cell lines and tissues from human and mouse. Furthermore, we demonstrate that the SPG assay was reproducible across multiple users. When used in conjunction with advanced cellular neighborhood segmentation, distinct immune or tumor RNA and protein targets were spatially resolved within individual cell subpopulations in human colorectal cancer and non-small cell lung cancer. We used the SPG assay to interrogate 23 different glioblastoma multiforme (GBM) samples across four pathologies. The study revealed distinct clustering of both RNA and protein based on pathology and anatomic location. The in-depth investigation of giant cell glioblastoma multiforme (gcGBM) revealed distinct protein and RNA expression profiles compared with that of the more common GBM. More importantly, the use of spatial proteogenomics allowed simultaneous interrogation of critical protein posttranslational modifications alongside whole transcriptomic profiles within the same distinct cellular neighborhoods.

Significance

We describe ultra high-plex spatial proteogenomics; profiling whole transcriptome and high-plex proteomics on a single FFPE tissue section with spatial resolution. Investigation of gcGBM versus GBM revealed distinct protein and RNA expression profiles.

A novel lysosome-related gene signature coupled with gleason score for prognosis prediction in prostate cancer

Background: Prostate cancer (PCa) is highly heterogeneous, which makes it difficult to precisely distinguish the clinical stages and histological grades of tumor lesions, thereby leading to large amounts of under- and over-treatment. Thus, we expect the development of novel prediction approaches for the prevention of inadequate therapies. The emerging evidence demonstrates the pivotal role of lysosome-related mechanisms in the prognosis of PCa. In this study, we aimed to identify a lysosome-related prognostic predictor in PCa for future therapies.

Methods: The PCa samples involved in this study were gathered from The Cancer Genome Atlas database (TCGA) (n = 552) and cBioPortal database (n = 82). During screening, we categorized PCa patients into two immune groups based on median ssGSEA scores. Then, the Gleason score and lysosome-related genes were included and screened out by using a univariate Cox regression analysis and the least absolute shrinkage and selection operation (LASSO) analysis. Following further analysis, the probability of progression free interval (PFI) was modeled by using unadjusted Kaplan–Meier estimation curves and a multivariable Cox regression analysis. A receiver operating characteristic (ROC) curve, nomogram and calibration curve were used to examine the predictive value of this model in discriminating progression events from non-events. The model was trained and repeatedly validated by creating a training set (n = 400), an internal validation set (n = 100) and an external validation (n = 82) from the cohort.

Results: Following grouping by ssGSEA score, the Gleason score and two LRGs—neutrophil cytosolic factor 1 (NCF1) and gamma-interferon-inducible lysosomal thiol reductase (IFI30)—were screened out to differentiate patients with or without progression (1-year AUC = 0.787; 3-year AUC = 0.798; 5-year AUC = 0.772; 10-year AUC = 0.832). Patients with a higher risk showed poorer outcomes (p &lt; 0.0001) and a higher cumulative hazard (p &lt; 0.0001). Besides this, our risk model combined LRGs with the Gleason score and presented a more accurate prediction of PCa prognosis than the Gleason score alone. In three validation sets, our model still achieved high prediction rates.

Conclusion: In conclusion, this novel lysosome-related gene signature, coupled with the Gleason score, works well in PCa for prognosis prediction.

IFITM3 blocks influenza virus entry by sorting lipids and stabilizing hemifusion

Interferon-induced transmembrane protein 3 (IFITM3) inhibits the entry of numerous viruses through undefined molecular mechanisms. IFITM3 localizes in the endosomal-lysosomal system and specifically affects virus fusion with target cell membranes. We found that IFITM3 induces local lipid sorting, resulting in an increased concentration of lipids disfavoring viral fusion at the hemifusion site. This increases the energy barrier for fusion pore formation and the hemifusion dwell time, promoting viral degradation in lysosomes. In situ cryo-electron tomography captured IFITM3-mediated arrest of influenza A virus membrane fusion. Observation of hemifusion diaphragms between viral particles and late endosomal membranes confirmed hemifusion stabilization as a molecular mechanism of IFITM3. The presence of the influenza fusion protein hemagglutinin in post-fusion conformation close to hemifusion sites further indicated that IFITM3 does not interfere with the viral fusion machinery. Collectively, these findings show that IFITM3 induces lipid sorting to stabilize hemifusion and prevent virus entry into target cells.

A Near-Infrared Fluorescent and Photoacoustic Probe for Visualizing Biothiols Dynamics in Tumor and Liver

Biothiols, including glutathione (GSH), homocysteine (Hcy) and cysteine (Cys), play crucial roles in various physiological processes. Though an array of fluorescent probes have been designed to visualize biothiols in living organisms, few one-for-all imaging agents for sensing biothiols with fluorescence and photoacoustic imaging capabilities have been reported, since instructions for synchronously enabling and balancing every optical imaging efficacy are deficient. Herein, a new near-infrared thioxanthene-hemicyanine dye (Cy-DNBS) has been constructed for fluorescence and photoacoustic imaging of biothiols in vitro and in vivo. Upon treatment with biothiols, the absorption peak of Cy-DNBS shifted from 592 nm to 726 nm, resulting in a strong NIR absorption as well as a subsequent turn-on PA signal. Meanwhile, the fluorescence intensity increased instantaneously at 762 nm. Then, Cy-DNBS was successfully utilized for imaging endogenous and exogenous biothiols in HepG2 cells and mice. In particular, Cy-DNBS was employed for tracking biothiols upregulation in the liver of mice triggered by S-adenosyl methionine by means of fluorescent and photoacoustic imaging methods. We expect that Cy-DNBS serves as an appealing candidate for deciphering biothiols-related physiological and pathological processes.

LncRNA-mRNA integrated profiling analysis in response to white spot syndrome virus in hepatopancreas in Penaeus japonicus

Penaeus japonicas is an important shrimp species, which is exposed to stressors including a variety of epidemic diseases. To date, little is known about the mechanisms involved in the response to white spot syndrome virus (WSSV) mediated by long non-coding RNAs (lncRNAs). A total of 6544 putative lncRNAs were identified in the hepatopancreas in P. japonicas, which provides a useful lncRNA reference resource for use in future studies. In addition, a total of 444 differentially expressed mRNAs and 457 differentially expressed lncRNAs were identified at 6, 12, and 24 h after WSSV infection in the hepatopancreas of P. japonicas. Functional enrichment analysis showed that the differentially expressed mRNAs were enriched in terms related to immune response and viral infectivity such as defense response, aminopeptidase activity, whereas the differentially expressed lncRNA partner genes were enriched in ubiquitin-dependent protein catabolic process, lipoprotein metabolic process, and antigen processing and presentation. Moreover, several lncRNAs were induced by WSSV infection, indicating these lncRNAs might participate in regulating many immune processes referring to their partner genes. Co-expression analysis of the lncRNAs and their partner genes identified some high lncRNA-mRNA correlations. These results suggest that WSSV stimulates the immune response in the hepatopancreas potentially through an important coding and non-coding gene network, thereby providing valuable information regarding non-coding responses to WSSV in Penaeus species.

Development of a Liquid Chromatography and High-Resolution and -Accuracy Mass Spectrometry Method to Evaluate New Biotherapeutic Entity Processing in Human Liver Lysosomes

Biotherapeutic immunogenicity remains a great challenge for researchers because multiple factors trigger immune responses. Predicting and assessing the potential human immune response against biological drugs could represent an impressive breakthrough toward generating potentially safer and more efficacious therapeutic proteins. This article describes an in vitro assay that can contribute to evaluating the potential immunogenicity of biotherapeutics by focusing on lysosomal proteolysis. We selected human liver lysosomes (hLLs) from four different donors as a surrogate in vitro model instead of APC lysosomes because they are a ready-to-use lysosomal source. To assess the biological comparability of this surrogate to APC lysosomal extract, we compared the proteome content of hLLs with literature data of lysosomal fractions extracted from murine bone marrow and human blood-derived dendritic cells. Then we tested infliximab (IFX; Remicade) under different proteolytic conditions using liquid chromatography and high-resolution and -accuracy mass spectrometry to better define the degradation kinetics inside the lysosomes. hLLs revealed similar enzymatic content compared with human and murine dendritic cell lysosomes. Degradation assays demonstrated that our liquid chromatography and high-resolution and -accuracy mass spectrometry method could identify both the intact protein and the peptides resulting from proteolysis with high specificity and resolution. The rapid and easy assay described in this article can be extremely useful for evaluating the immunogenic risk associated with therapeutic proteins. In addition, this method can complement information from MHC class II-associated peptide proteomics assays and other in vitro and in silico techniques.

High GILT Expression Is Associated with Improved Survival in Metastatic Melanoma Patients Treated with Immune Checkpoint Inhibition

Simple Summary

Skin cancer is the most common type of cancer, with melanoma being among the deadliest of skin cancers due to its propensity to metastasize. Immune checkpoint inhibitors (ICI) generate anti-tumor immune responses resulting in improved outcomes in patients with metastatic melanoma. However, only a subset of melanoma patients responds to these therapies, which are costly and come with a risk of adverse effects. Therefore, there is a need for biomarkers to predict which patients will respond to ICI. We found that ICI-treated metastatic melanoma patients with high GILT mRNA expression in bulk tumor samples had improved survival. Additionally, high GILT protein expression within metastatic melanoma cells was associated with improved survival in patients treated with ICI. This study suggests that GILT may serve as a biomarker to predict which patients will respond to ICI, which could improve patient care, reduce healthcare costs, and facilitate appropriate selection of therapies for patients with metastatic melanoma.

Abstract

Gamma-interferon-inducible lysosomal thiol reductase (GILT) is critical for MHC class II restricted presentation of multiple melanoma antigens. There is variable GILT protein expression in malignant melanocytes in melanoma specimens. High GILT mRNA expression in melanoma specimens is associated with improved overall survival, before the advent of immune checkpoint inhibitors (ICI). However, the association of GILT in metastatic melanoma with survival in patients treated with ICI and the cell type expressing GILT associated with survival have not been determined. Using RNA sequencing datasets, high GILT mRNA expression in metastatic melanoma specimens was associated with improved progression-free and overall survival in patients treated with ICI. A clinical dataset of metastatic melanoma specimens was generated and annotated with clinical information. Positive GILT immunohistochemical staining in antigen presenting cells and melanoma cells was observed in 100% and 65% of metastatic melanoma specimens, respectively. In the subset of patients treated with ICI in the clinical dataset, high GILT protein expression within melanoma cells was associated with improved overall survival. The association of GILT mRNA and protein expression with survival was independent of cancer stage. These studies support that high GILT mRNA expression in bulk tumor samples and high GILT protein expression in melanoma cells is associated with improved survival in ICI-treated patients. These findings support further investigation of GILT as a biomarker to predict the response to ICI.

Biodegradable and Dual-Responsive Polypeptide-Shelled Cyclodextrin-Containers for Intracellular Delivery of Membrane-Impermeable Cargo

The transport of membrane impermeable compounds into cells is a prerequisite for the efficient cellular delivery of hydrophilic and amphiphilic compounds and drugs. Transport into the cell's cytosolic compartment should ideally be controllable and it should involve biologically compatible and degradable vehicles. Addressing these challenges, nanocontainers based on cyclodextrin amphiphiles that are stabilized by a biodegradable peptide shell are developed and their potential to deliver fluorescently labeled cargo into human cells is analyzed. Host-guest mediated self-assembly of a thiol-containing short peptide or a cystamine-cross-linked polypeptide shell on cyclodextrin vesicles produce short peptide-shelled (SPSVss ) or polypeptide-shelled vesicles (PPSVss ), respectively, with redox-responsive and biodegradable features. Whereas SPSVss are permeable and less stable, PPSVss effectively encapsulate cargo and show a strictly regulated release of membrane impermeable cargo triggered by either reducing conditions or peptidase treatment. Live cell experiments reveal that the novel PPSVSS are readily internalized by primary human endothelial cells (human umbilical vein endothelial cells) and cervical cancer cells and that the reductive microenvironment of the cells' endosomes trigger release of the hydrophilic cargo into the cytosol. Thus, PPSVSS represent a highly efficient, biodegradable, and tunable system for overcoming the plasma membrane as a natural barrier for membrane-impermeable cargo.

Fluorescent Probes for Live Cell Thiol Detection

Thiols play vital and irreplaceable roles in the biological system. Abnormality of thiol levels has been linked with various diseases and biological disorders. Thiols are known to distribute unevenly and change dynamically in the biological system. Methods that can determine thiols' concentration and distribution in live cells are in high demand. In the last two decades, fluorescent probes have emerged as a powerful tool for achieving that goal for the simplicity, high sensitivity, and capability of visualizing the analytes in live cells in a non-invasive way. They also enable the determination of intracellular distribution and dynamitic movement of thiols in the intact native environments. This review focuses on some of the major strategies/mechanisms being used for detecting GSH, Cys/Hcy, and other thiols in live cells via fluorescent probes, and how they are applied at the cellular and subcellular levels. The sensing mechanisms (for GSH and Cys/Hcy) and bio-applications of the probes are illustrated followed by a summary of probes for selectively detecting cellular and subcellular thiols.

miR-145 micelles mitigate atherosclerosis by modulating vascular smooth muscle cell phenotype

In atherosclerosis, resident vascular smooth muscle cells (VSMCs) in the blood vessels become highly plastic and undergo phenotypic switching from the quiescent, contractile phenotype to the migratory and proliferative, synthetic phenotype. Additionally, recent VSMC lineage-tracing mouse models of atherosclerosis have found that VSMCs transdifferentiate into macrophage-like and osteochondrogenic cells and make up to 70% of cells found in atherosclerotic plaques. Given VSMC phenotypic switching is regulated by microRNA-145 (miR-145), we hypothesized that nanoparticle-mediated delivery of miR-145 to VSMCs has the potential to mitigate atherosclerosis development by inhibiting plaque-propagating cell types derived from VSMCs. To test our hypothesis, we synthesized miR-145 micelles targeting the C-C chemokine receptor-2 (CCR2), which is highly expressed on synthetic VSMCs. When miR-145 micelles were incubated with human aortic VSMCs in vitro, >90% miR-145 micelles escaped the lysosomal pathway in 4 hours and released the miR cargo under cytosolic levels of glutathione, an endogenous reducing agent. As such, miR-145 micelles rescued atheroprotective contractile markers, myocardin, α-SMA, and calponin, in synthetic VSMCs in vitro. In early-stage atherosclerotic ApoE-/- mice, one dose of miR-145 micelles prevented lesion growth by 49% and sustained an increased level of miR-145 expression after 2 weeks post-treatment. Additionally, miR-145 micelles inhibited 35% and 43% plaque growth compared to free miR-145 and PBS, respectively, in mid-stage atherosclerotic ApoE-/- mice. Collectively, we present a novel therapeutic strategy and cell target for atherosclerosis, and present miR-145 micelles as a viable nanotherapeutic that can intervene atherosclerosis progression at both early and later stages of disease.

Polymeric nano-carriers for on-demand delivery of genes via specific responses to stimuli

Polymeric nano-carriers have been developed as a most capable and feasible technology platform for gene therapy. As vehicles, polymeric nano-carriers are obliged to possess high gene loading capability, low immunogenicity, safety, and the ability to transfer various genetic materials into specific sites of target cells to express therapeutic proteins or block a process of gene expression. To this end, various types of polymeric nano-carriers have been prepared to release genes in response to stimuli such as pH, redox, enzymes, light and temperature. These stimulus-responsive nano-carriers exhibit high gene transfection efficiency and low cytotoxicity. In particular, dual- and multi-stimulus-responsive polymeric nano-carriers can respond to a combination of signals. Markedly, these combined responses take place either simultaneously or in a sequential manner. These dual-stimulus-responsive polymeric nano-carriers can control gene delivery with high gene transfection both in vitro and in vivo. In this review paper, we highlight the recent exciting developments in stimulus-responsive polymeric nano-carriers for gene delivery applications.

Freezing-then-aging treatment improved the protein digestibility of beef in an in vitro infant digestion model

In vitro protein digestibility of freezing-then-aged beef was investigated in an infant digestion model. The treatments were divided into freezing-then-aging (FA) and aging-only (AO) groups. Carbonyl and total free sulfhydryl contents were the same between both groups for 14-day aging. Freezing had no effect on beef myofibrillar protein tertiary structure. Although caspase-3 activity did not differ, the FA group showed higher cathepsin B activity than the AO group (p < 0.05). The 10% trichloroacetic acid-soluble α-amino content was higher in FA than AO group, on aging day 14 (p < 0.05). Post in vitro digestion of beef aged for 14 days, the FA group had a higher content, than the AO group, of α-amino groups and proteins digested under 3 kDa (p < 0.05). An electrophoretogram of the digesta showed improved digestion of actin in the FA group. Collectively, the freezing-then-aging process enhanced the protein digestibility of beef in this in vitro infant digestion model.

Recent Advances in Organelle-Targeted Fluorescent Probes

Recent advances in fluorescence imaging techniques and super-resolution microscopy have extended the applications of fluorescent probes in studying various cellular processes at the molecular level. Specifically, organelle-targeted probes have been commonly used to detect cellular metabolites and transient chemical messengers with high precision and have become invaluable tools to study biochemical pathways. Moreover, several recent studies reported various labeling strategies and novel chemical scaffolds to enhance target specificity and responsiveness. In this review, we will survey the most recent reports of organelle-targeted fluorescent probes and assess their general strategies and structural features on the basis of their target organelles. We will discuss the advantages of the currently used probes and the potential challenges in their application as well as future directions.

IFI30 expression predicts patient prognosis in breast cancer and dictates breast cancer cells proliferation via regulating autophagy

Introduction: Incidence and mortality rates of breast cancer are increasing in women worldwide. Immunotherapy is a relatively popular treatment modality for all malignant tumors including breast cancer in recent years. Interferon γ-inducible protein 30 (IFI30) could catalyze the reduction of disulfide bonds and enhance major histocompatibility complex (MHC) class II-restricted antigen processing. Recent studies showed that IFI30 played an important role in the immune response of malignant tumors. Methods: The Cancer Genome Atlas (TCGA) database and clinical proteomic tumor Analysis consortium (CPTAC) database were applied to predict the role of IFI30 in breast cancer and the relationship between IFI30 and prognosis of breast cancer patients. Then we detected the expression of IFI30 in clinical samples of breast cancer patients, and analyzed the relationship between IFI30 and the prognosis of breast cancer patients. We used lentivirus infection method to construct a stable IFI30 knockdown cell line, and detected the effect of IFI30 in breast cancer cells. Nude mice tumor bearing experiment was performed to investigate the effect of IFI30 on breast cancer cells in vivo. Western blot was used to verify the regulation of autophagy related protein LC3 and p62 by IFI30. Results: We found that IFI30 was highly expressed in breast cancer tissues and was associated with poor outcome of patients. The knockdown of IFI30 could inhibit the proliferation, migration and invasion of breast cancer cells and significantly inhibit tumor growth in vivo. Increased accumulation of LC3-II and p62 suggested impaired autophagy in IFI30 knockdown cells. Discussion: As a result, we suggested that IFI30 might play a key role in the initiation and progression of human breast cancer and might be a new therapeutic target in breast cancer.

TFEB Transcriptional Responses Reveal Negative Feedback by BHLHE40 and BHLHE41

Transcription factor EB (TFEB) activates lysosomal biogenesis genes in response to environmental cues. Given implications of impaired TFEB signaling and lysosomal dysfunction in metabolic, neurological, and infectious diseases, we aim to systematically identify TFEB-directed circuits by examining transcriptional responses to TFEB subcellular localization and stimulation. We reveal that steady-state nuclear TFEB is sufficient to activate transcription of lysosomal, autophagy, and innate immunity genes, whereas other targets require higher thresholds of stimulation. Furthermore, we identify shared and distinct transcriptional signatures between mTOR inhibition and bacterial autophagy. Using a genome-wide CRISPR library, we find TFEB targets that protect cells from or sensitize cells to lysosomal cell death. BHLHE40 and BHLHE41, genes responsive to high, sustained levels of nuclear TFEB, act in opposition to TFEB upon lysosomal cell death induction. Further investigation identifies genes counter-regulated by TFEB and BHLHE40/41, adding this negative feedback to the current understanding of TFEB regulatory mechanisms.

Development on Citrus medica infected with 'Candidatus Liberibacter asiaticus' has sex-specific and -nonspecific impacts on adult Diaphorina citri and its endosymbionts

Huanglongbing (HLB) is a deadly, incurable citrus disease putatively caused by the unculturable bacterium, 'Candidatus Liberibacter asiaticus' (CLas), and transmitted by Diaphorina citri. Prior studies suggest D. citri transmits CLas in a circulative and propagative manner; however, the precise interactions necessary for CLas transmission remain unknown, and the impact of insect sex on D. citri-CLas interactions is poorly understood despite reports of sex-dependent susceptibilities to CLas. We analyzed the transcriptome, proteome, metabolome, and microbiome of male and female adult D. citri reared on healthy or CLas-infected Citrus medica to determine shared and sex-specific responses of D. citri and its endosymbionts to CLas exposure. More sex-specific than shared D. citri responses to CLas were observed, despite there being no difference between males and females in CLas density or relative abundance. CLas exposure altered the abundance of proteins involved in immunity and cellular and oxidative stress in a sex-dependent manner. CLas exposure impacted cuticular proteins and enzymes involved in chitin degradation, as well as energy metabolism and abundance of the endosymbiont 'Candidatus Profftella armatura' in both sexes similarly. Notably, diaphorin, a toxic Profftella-derived metabolite, was more abundant in both sexes with CLas exposure. The responses reported here resulted from a combination of CLas colonization of D. citri as well as the effect of CLas infection on C. medica. Elucidating these impacts on D. citri and their endosymbionts contributes to our understanding of the HLB pathosystem and identifies the responses potentially critical to limiting or promoting CLas acquisition and propagation in both sexes.

Development of lipid-like materials for RNA delivery based on intracellular environment-responsive membrane destabilization and spontaneous collapse

Messenger RNA and small interfering RNA are attractive modalities for curing diseases by complementation or knock-down of proteins. For success of these RNAs, a drug delivery system (DDS) is required to control a pharmacokinetics, to enhance cellular uptake, to overcome biological membranes, and to release the cargo into the cytoplasm. Based on past research, developing nanoparticles that are neutrally charged have been the mainstream of their development. Also, the materials are further mounted with pH- and/or reducing environment-responsive units. In this review, we summarize progress made in the molecular design of these materials. We also focus on the importance of the hydrophobic scaffold for tissue/cell targeting, intracellular trafficking, and immune responses. As a practical example, the design concept of the SS-cleavable and pH-activated lipid-like material (ssPalm) and subsequent molecular modification tailored to the RNA-based medical application is discussed.

Secretory Production of Functional Grouper Type I Interferon from Epinephelus septemfasciatus in Escherichia coli and Bacillus subtilis

Nervous necrosis virus (NNV) results in high mortality rates of infected marine fish worldwide. Interferons (IFNs) are cytokines in vertebrates that suppress viral replication and regulate immune responses. Heterologous overexpression of fish IFN in bacteria could be problematic because of protein solubility and loss of function due to protein misfolding. In this study, a protein model of the IFN-α of Epinephelus septemfasciatus was built based on comparative modeling. In addition, PelB and SacB signal peptides were fused to the N-terminus of E. septemfasciatus IFN-α for overexpression of soluble, secreted IFN in Escherichia coli (E-IFN) and Bacillus subtilis (B-IFN). Cytotoxicity tests indicated that neither recombinant grouper IFN-α were cytotoxic to a grouper head kidney cell line (GK). The GK cells stimulated with E-IFN and B-IFN exhibited elevated expression of antiviral Mx genes when compared with the control group. The NNV challenge experiments demonstrated that GK cells pretreated or co-treated with E-IFN and B-IFN individually had three times the cell survival rates of untreated cells, indicating the cytoprotective ability of our recombinant IFNs. These data provide a protocol for the production of soluble, secreted, and functional grouper IFN of high purity, which may be applied to aquaculture fisheries for antiviral infection.

Disulfide-containing Macromolecules for Therapeutic Delivery

Development of macromolecules provides applicable platforms for the delivery of therapeutics. In this general overview, we focus on the design principles of synthetic polymers, with disulfide bonds located in either the polymer backbone or side chains. We also discuss the role of disulfide bonds, as well as the remaining questions to better understand their applications in therapeutic delivery systems.

Identification and Characterization of an OSH1 Thiol Reductase from Populus Trichocarpa

Interferon gamma-induced lysosomal thiol reductase (GILT) is abundantly expressed in antigen-presenting cells and participates in the treatment and presentation of antigens by major histocompatibility complex II. Also, GILT catalyzes the reduction of disulfide bonds, which plays an important role in cellular immunity. (1) Background: At present, the studies of GILT have mainly focused on animals. In plants, GILT homologous gene (Arabidopsis thalianaOSH1: AtOSH1) was discovered in the forward screen of mutants with compromised responses to sulphur nutrition. However, the complete properties and functions of poplar OSH1 are unclear. In addition, CdCl2 stress is swiftly engulfing the limited land resources on which humans depend, restricting agricultural production. (2) Methods: A prokaryotic expression system was used to produce recombinant PtOSH1 protein, and Western blotting was performed to identify its activity. In addition, a simplified version of the floral-dip method was used to transform A. thaliana. (3) Results: Here, we describe the identification and characterization of OSH1 from Populus trichocarpa. The deduced PtOSH1 sequence contained CQHGX2ECX2NX4C and CXXC motifs. The transcript level of PtOSH1 was increased by cadmium (Cd) treatment. In addition, recombinant PtOSH1 reduced disulfide bonds. A stress assay showed that PtOSH1-overexpressing (OE) A. thaliana lines had greater resistance to Cd than wild-type (WT) plants. Also, the activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in PtOSH1-OE plants were significantly higher than those in WT A. thaliana. These results indicate that PtOSH1 likely plays an important role in the response to Cd by regulating the reactive oxygen species (ROS)-scavenging system. (4) Conclusions: PtOSH1 catalyzes the reduction of disulfide bonds and behaves as a sulfhydryl reductase under acidic conditions. The overexpression of PtOSH1 in A. thaliana promoted root development, fresh weight, and dry weight; upregulated the expression levels of ROS scavenging-related genes; and improved the activity of antioxidant enzymes, enhancing plant tolerance to cadmium (Cd) stress. This study aimed to provide guidance that will facilitate future studies of the function of PtOSH1 in the response of plants to Cd stress.

Identification of the quantitative trait loci controlling spike-related traits in hexaploid wheat (Triticum aestivum L.)

Totally, 48 loci responsible for six spike-related traits were identified in wheat, and a major locus QGl-4A for grain length was mapped and validated for marker-assisted selection in breeding. Wheat yield is determined by the number of spikes, number of grains per spike (GN), and one-thousand kernel weight (TKW), among which GN and TKW are greatly related to the spike development and thus the spike-related traits, including spike length (SL), number of spikelet per spike (SN), grain length (GL) and grain width (GW). To identify the key loci governing the spike-related traits (SL, SN, GN, TKW, GL and GW), we conducted the quantitative trait loci (QTL) analysis combined with wheat 660K SNP chip and Kompetitive allele-specific PCR (KASP) assay, using the F₂ and F_2:3 populations derived from Luohan6 (LH6) with big spike and grain and Zhengmai366 with small spike and grain, and identified a total of 48 QTLs on 18 chromosomes. Moreover, a major stable QTL for GL on chromosome 4A, designated as QGl-4A, was mapped into a 0.37 cM interval between KASP markers Xib4A-10 and Xib4A-12, corresponding to 20 Mb physical region in the Chinese Spring genome. This QTL explained 17.30% and 5.12% of the phenotypic variation for GL in the F₂ and F_2:3 populations. Further association analysis of flanking markers Xib4A-10 and Xib4A-12 in 192 wheat varieties showed that these two markers could be used for marker-assisted selection in breeding. These results provide valuable information for map-based cloning of the target genes involved in the regulation of spike-related traits in common wheat.

Responsive Antibody Conjugates Enable Quantitative Determination of Intracellular Bond Degradation Rate

Degradable crosslinkers that respond to intracellular biological stimuli are a critical component of many drug delivery systems. With numerous stimuli-responsive drug delivery systems in development, it is important to quantitatively study their intracellular processing. Herein we report a framework for quantifying the rate of intracellular bond degradation in the endocytic pathway. Toward this end, we devised and synthesized a reduction-sensitive FRET-based crosslinker that can be readily conjugated to a variety of targeting ligands. This crosslinker was conjugated to trastuzumab, a humanized monoclonal antibody against the HER2 receptor. We developed a model based on mass-action kinetics to describe the intracellular processing of this conjugate. The kinetic model was developed in conjunction with live-cell experiments to extract the rate constant for intracellular disulfide bond degradation. This framework may be applied to other endocytosis pathways, bond types, and cell types to quantify this fundamental degradation rate parameter.

Human Cysteine Cathepsins Degrade Immunoglobulin G In Vitro in a Predictable Manner

Cysteine cathepsins are critical components of the adaptive immune system involved in the generation of epitopes for presentation on human leukocyte antigen (HLA) molecules and have been implicated in degradation of autoantigens. Immunoglobulin variable regions with somatic mutations and random complementarity region 3 amino acid composition are inherently immunogenic. T cell reactivity towards immunoglobulin variable regions has been investigated in relation to specific diseases, as well as reactivity to therapeutic monoclonal antibodies. Yet, how the immunoglobulins, or the B cell receptors, are processed in endolysosomal compartments of professional antigen presenting cells has not been described in detail. Here we present in silico and in vitro experimental evidence suggesting that cysteine cathepsins S, L and B may have important roles in generating peptides fitting HLA class II molecules, capable of being presented to T cells, from monoclonal antibodies as well as from central nervous system proteins including a well described autoantigen. By combining neural net models with in vitro proteomics experiments, we further suggest how such degradation can be predicted, how it fits with available cellular models, and that it is immunoglobulin heavy chain variable family dependent. These findings are relevant for biotherapeutic drug design as well as to understand disease development. We also suggest how these tools can be improved, including improved machine learning methodology.

Low-dose cadmium potentiates lung inflammatory response to 2009 pandemic H1N1 influenza virus in mice

Cadmium (Cd) is a toxic, pro-inflammatory metal ubiquitous in the diet that accumulates in body organs due to inefficient elimination. Responses to influenza virus infection are variable, particularly severity of pneumonia. We used a murine model of chronic low-dose oral exposure to Cd to test if increased lung tissue Cd worsened inflammation in response to sub-lethal H1N1 infection. The results show that Cd-treated mice had increased lung tissue inflammatory cells, including neutrophils, monocytes, T lymphocytes and dendritic cells, following H1N1 infection. Lung genetic responses to infection (increasing TNF-α, interferon and complement, and decreasing myogenesis) were also exacerbated. To reveal the organization of a network structure, pinpointing molecules critical to Cd-altered lung function, global correlations were made for immune cell counts, leading edge gene transcripts and metabolites. This revealed that Cd increased correlation of myeloid immune cells with pro-inflammatory genes, particularly interferon-γ and metabolites. Together, the results show that Cd burden in mice increased inflammation in response to sub-lethal H1N1 challenge, which was coordinated by genetic and metabolic responses, and could provide new targets for intervention against lethal inflammatory pathology of clinical H1N1 infection.

Identification and functional characterization of interferon-γ-inducible lysosomal thiol reductase (GILT) gene in common Chinese cuttlefish Sepiella japonica

Interferon-γ-inducible lysosomal thiol reductase (GILT) is a pivotal enzyme involved in the histocompatibility complex (MHC) class II-restricted antigen processing whereby it catalyzes the disulfide bond reduction in the endocytic pathway. Here, a novel GILT homologue termed as SjGILT firstly identified from common Chinese cuttlefish Sepiella japonica. SjGILT shared domain topology containing a signal peptide, a signature sequence CQHGX₂ECX₂NX₄C, an activate-site CXXC motif, two potential N-glycosylation sites and six conserved cysteins with its counterparts in other animals. SjGILT transcripts were constitutively expressed in all examined tissues in S. japonica, with the higher expression levels in immune-related tissues such as pancreas, intestines, liver and gills. Upon lipopolysaccharide (LPS) challenge, SjGILT transcripts were significantly induced in liver and gill tissues, and SjGILT protein transferred to late endosomes and lysosomes in HeLa cells. Further study showed that recombinant SjGILT had obvious thiol reductase activity demonstrated by reducing the interchain disulfide bonds of IgG under acidic conditions. Taken together, these results suggested that SjGILT may be involved in the immune response to bacteria challenge, and then might play an important role in the processing of MHC class II-restricted antigens in S. japonica.

A novel antimicrobial peptide-derived vehicle for oligodeoxynucleotide delivery to inhibit TNF-α expression

Indolicidin (IL), an antimicrobial peptide, was investigated as a vehicle to promote oligodeoxynucleotides (ODNs) delivery. To increase charge density, IL was dimerized by adding a cysteine to its C or N terminus, which was denoted as ILC or CIL, respectively. In contrast to IL, cytotoxicity of ILC and CIL was significantly reduced because these dimeric peptides were longer than IL, which restricted their insertions to cell membrane. In contrast to ILC, CIL displayed well loading efficiency. These peptides were applied to deliver ODNs against tumor necrosis factor-α (TNF-α) because TNF-α is a pro-inflammatory cytokine which plays an important role in immunological diseases. Although IL/ODN slightly reduced TNF-α expression, the high cytotoxicity restricted its application window. Furthermore, ILC/ODN was incapable of inducing gene silence due to its low encapsulation efficiency and poor endosomal escape. In contrast, CIL exhibited excellent ODN transportation and the internalized CIL/ODN complexes may escape from endosomes. Therefore, TNF-α expression can be specifically reduced by CIL/ODN complexes, and the silence effect was maintained longer than 14 h. This study provides a useful strategy of peptide vehicle design, which may facilitate the delivery of not only ODN but also other oligonucleotides, including siRNA and miRNA, to promote gene silence application.

Identification and characterization of the interferon-γ-inducible lysosomal thiol reductase gene in Chinese soft-shelled turtle, Pelodiscus sinensis

The reduction of disulfide bonds of exogenous antigens is crucial to the MHC-II class antigen processing and presenting pathway and is catalysed by interferon-γ-inducible lysosomal thiol reductase (GILT). In this study, a reptile GILT gene from Chinese soft-shelled turtle, Pelodiscus sinensis (PsGILT), was identified. The full-length cDNA of PsGILT is 1631 nucleotides (nt), including a 5'-untranslated region (UTR) of 3 nt, a 3'-UTR of 860 nt and an open reading frame (ORF) of 768 nt encoding 255 amino acids (aa). The conserved features in known GILTs, such as signal peptide, CXXC motif, GILT signature sequence, N-glycosylation site and conserved cysteines, were all found in the putative PsGILT protein. Genomic analysis revealed that PsGILT kept the "7 exons and 6 introns" structure of vertebrate GILT genes. PsGILT was expressed in all examined organs/tissues and was mainly expressed in spleen and blood. Increased mRNA expression levels of PsIFN-γ and PsGILT in PBLs were observed after induction with LPS, PolyI:C and recombinant IFN-γ (rIFN-γ). We also tested the reductase activity of rGILT in vitro and found that it could reduce intact human IgG into H chains and L chains. These above results implied that PsGILT may play an important role in resisting bacterial and viral infections, like other vertebrate GILTs.

Microglia express gamma-interferon-inducible lysosomal thiol reductase in the brains of Alzheimer's disease and Nasu-Hakola disease

Gamma-interferon-inducible lysosomal thiol reductase (GILT), expressed in antigen-presenting cells (APCs), facilitates the reduction of disulfide bonds of endocytosed proteins in the endocytic pathway and they are further processed for presentation of immunogenic peptides loaded on major histocompatibility complex (MHC) class II. Although the constitutive and IFNγ-inducible expression of GILT was observed in various APCs, such as dendritic cells, monocytes/macrophages, and B cells, GILT-expressing cell types remain unknown in the human central nervous system (CNS). Nasu-Hakola disease (NHD) is a rare autosomal recessive disorder characterized by sclerosing leukoencephalopathy and multifocal bone cysts, caused by a loss-of-function mutation of either TYROBP (DAP12) or TREM2, both of which are expressed on microglia. A rare heterozygous variant of the TREM2 gene encoding p.Arg47His causes a 3-fold increase in the risk for late-onset Alzheimer's disease (LOAD), suggesting that both NHD and AD are induced by dysfunction of the microglial TREM2 signaling pathway in the brains. We studied by immunohistochemistry GILT expression in NHD and AD brains. GILT was expressed on amoeboid microglia with the highest levels of expression in AD brains, compared with those in non-neurological control (NC) brains and in NHD brains. In AD brains, the clusters of amoeboid microglia surrounding amyloid-beta (Aꞵ) deposition strongly expressed GILT. Furthermore, a human microglial cell line expressed GILT in response to IFNγ. These results indicate that microglia, expressing constitutively high levels of GILT, act as a principal cell type of APCs in AD brains, in contrast to baseline levels of GILT expression in NHD brains.

Association of NOX2 subunits genetic variants with autoimmune diseases

A single nucleotide polymorphism in Ncf1 has been found with a major effect on chronic inflammatory autoimmune diseases in the rat with the surprising observation that a lower reactive oxygen response led to more severe diseases. This finding was subsequently reproduced in the mouse and the effect operates in many different murine diseases through different pathogenic pathways; like models for rheumatoid arthritis, encephalomyelitis, lupus, gout, psoriasis and psoriatic arthritis. The human gene is located in an unstable region with many variable sequence repetitions, which means it has not been included in any genome wide associated screens so far. However, identification of copy number variations and single nucleotide polymorphisms has now clearly shown that major autoimmune diseases are strongly associated with the Ncf1 locus. In systemic lupus erythematosus the associated Ncf1 polymorphism (leading to an amino acid substitution at position 90) is the strongest locus and is associated with a lower reactive oxidative burst response. In addition, more precise mapping analysis of polymorphism of other NOX2 genes reveals that these are also associated with autoimmunity. The identified genetic association shows the importance of redox control and that ROS regulate chronic inflammation instead of promoting it. The genetic identification of Ncf1 polymorphisms now opens for relevant studies of the regulatory mechanisms involved, effects that will have severe consequences in many different pathogenic pathways and understanding of the origin of autoimmune diseases.

Molecular and biological characterization of gamma-interferon-inducible lysosomal thiol reductase in silver carp (Hypophthalmichthys molitrix)

Gamma-interferon-inducible lysosomal thiol reductase (GILT) plays an important role in the processing of major histocompatibility complex (MHC) class II-restricted antigens by catalyzing disulfide bonds reduction. Herein, a GILT homolog (ScGILT) was identified from silver carp. Its open reading frame covers 771 base pairs, encoding a protein of 256 amino acids that possesses GILT signature sequence CQHGX₂ECX₂NX₄C, active-site CXXC motif, and two potential N-linked glycosylation sites. The predicted tertiary structures of ScGILT and other GILTs were quite similar in shape and positional arrangement of the key motifs. ScGILT mRNA was constitutively expressed in all detected tissues, with high-level expression in fish immune organs, spleen and head kidney. After stimulation with lipopolysaccharide, the expression of ScGILT mRNA significantly increased in spleen and head kidney cells, and ScGILT protein translocated to late endosomes and lysosomes in HeLa cells. Recombinant ScGILT fused with a His₆ tag was expressed and purified, and could reduce the interchain disulfide bonds of IgG at pH 4.5. These results suggested that ScGILT was capable of catalyzing disulfide bonds reduction, and then might play an important role in the processing of MHC class II-restricted antigens in silver carp.

Glutathione-sensitive hollow mesoporous silica nanoparticles for controlled drug delivery

Tunable glutathione (GSH)-sensitive hollow mesoporous silica nanoparticles (HMSiO2 NPs) were developed using a structural difference-based selective etching strategy. These organosilica hollow nanoparticles contained disulfide linkages (S-S) in the outer shell which were degraded by GSH. The particles were compared with their nonGSH-sensitive tetraethyl orthosilicate (TEOS) HMSiO2 counterparts in terms of their synthesis method, characterization, doxorubicin (DOX) release profile, and in vitro cytotoxicity in MCF-7 breast cancer cells. Transmission electron microscopy (TEM) of the particles indicated that the fabricated HMSiO2 NPs had an average diameter of 130 ± 5 nm. Thermogravimetric analysis (TGA) revealed that GSH-sensitive particles had approximately 5.3% more weight loss than TEOS HMSiO2 NPs. Zeta potential of these redox-responsive particles was -23 ± 1 mV at pH 6 in deionized (DI) water. Nitrogen adsorption-desorption isotherm revealed that the surface area of the hollow mesoporous nanoreservoirs was roughly 446 ± 6 m2 g-1 and the average diameter of the pores was 2.3 ± 0.5 nm. TEM images suggest that the nanoparticles started to lose mass integrity from Day 1. The particles showed a high loading capacity for DOX (8.9 ± 0.5%) as a model drug, due to the large voids existing in the hollow structures. Approximately 58% of the incorporated DOX released within 14 days in phosphate buffered saline (PBS) at pH 6 and in the presence of 10 mM of GSH, mimicking intracellular tumor microenvironment while release from TEOS HMSiO2 NPs was only c.a. 18%. The uptake of these hollow nanospheres by MCF-7 cells and RAW 264.7 macrophages was evaluated using TEM and confocal microscopy. The nanospheres were shown to accumulate in the endolysosomal compartments after incubation for 24 h with the maximum uptake of c.a. 2.1 ± 0.3% and 5.2 ± 0.4%, respectively. Cytotoxicity of the nanospheres was investigated using CCK-8 assay. Results indicate that intact hollow particles (both GSH-sensitive and TEOS HMSiO2 NPs) were nontoxic to MCF-7 cells after incubation for 24 h within the concentration range of 0-1000 μg ml-1. DOX-loaded GSH-sensitive nanospheres containing 6 μg ml-1 of DOX killed c.a. 51% of MCF-7 cells after 24 h while TEOS HMSiO2 NPs killed c.a. 20% with the difference being statistically significant. Finally, cytotoxicity data in RAW 264.7 macrophages and NIH 3 T3 fibroblasts shows that intact GSH-sensitive HMSiO2 NPs did not show any toxic effects on these cells with the concentrations equal or <125 μg ml-1.

Transcriptome analysis of Pacific white shrimp (Litopenaeus vannamei) challenged by Vibrio parahaemolyticus reveals unique immune-related genes

Pacific white shrimp (Litopenaeus vannamei) is an important cultural species worldwide. However, Vibrio spp. infections have caused a great economic loss in Pacific white shrimp culture industry. The immune responses of Pacific white shrimp to the Vibrio spp. is not fully characterized. In this study, the transcriptomic profiles of L. vannamei hemocytes were explored by injecting with or without Vibrio parahaemolyticus. Totally, 42,632 high-quality unigenes were obtained from RNAseq data. Comparative genome analysis showed 2258 differentially expressed genes (DEGs) following the Vibrio challenge, including 1017 up-regulated and 1241 down-regulated genes. Eight DEGs were randomly selected for further validation by quantitative real-time RT-PCR (qRT-PCR) and the results showed that are consistent with the RNA-seq data. Due to the lack of predictable adaptive immunity, shrimps rely on an innate immune system to defend themselves against invading microbes by recognizing and clearing them through humoral and cellular immune responses. Here we focused our studies on the humoral immunity, five genes (SR, MNK, CTL3, GILT, and ALFP) were selected from the transcriptomic data, which were significantly up-regulated by V. parahaemolyticus infection. These genes were widely expressed in six different tissues and were up-regulated by both Gram negative bacteria (V. parahaemolyticus) and Gram positive bacteria (Staphylococcus aureus). To further extend our studies, we knock-down those five genes by dsRNA in L. vannamei and analyzed the functions of specific genes against V. parahaemolyticus and S. aureus by bacterial clearance analysis. We found that the ability of L. vannamei was significantly reduced in bacterial clearance when treated with those specific dsRNA. These results indicate that those five genes play essential roles in antibacterial immunity and have its specific functions against different types of pathogens. The obtained data will shed a new light on the immunity of L. vannamei and pave a new way for fighting against the bacterial infection in Pacific white shrimp.

Genomic structure, expression pattern and polymorphisms of GILT in golden pompano Trachinotus ovatus (Linnaeus 1758)

The interferon-g-inducible lysosomal thiol reductase (GILT) plays a significant character in the processing and presentation of MHC class II restricted antigen (Ag) by catalyzing disulfide bond reduction in mammals. To explore the function of GILT in the immune system of fish, we cloned a GILT gene homologue from Trachinotus ovatus, the full-length cDNA of GILT, which consisted of 2, 747 bp with a 771 bp open reading frame, encoding a protein of 256 amino acids. Moreover, similar to other species GILT gene, 7 exons and 6 introns were identified in T. ovatus, the deduced protein also possessed a representative characteristic of known GILT proteins. The result of real-time quantitative PCR showed that GILT mRNA was dramatically expressed in immune-associated tissues, such as spleen (p < 0.01) and kidney (p < 0.05). Bacterial challenge revealed that GILT mRNA level remarkably up-regulation in liver, spleen, kidney and intestine after induction with Photobacterium damsela. Furthermore, based on cloned sequences and genome BLAST, only one SNP site (ToGILT-S1-g.148C>G) was identified, and the allele C was significantly associated with high-susceptibility (HS) group, nevertheless, the allele G was dramatically associated with high-resistance (HR) group, indicating potential application for disease resistant breeding selection in T. ovatus.

Gamma-interferon-inducible, lysosome/endosome-localized thiolreductase, GILT, has anti-retroviral activity and its expression is counteracted by HIV-1

The mechanism by which type II interferon (IFN) inhibits virus replications remains to be identified. Murine leukemia virus (MLV) replication was significantly restricted by γ-IFN, but not human immunodeficiency virus type 1 (HIV-1) replication. Because MLV enters host cells via endosomes, we speculated that certain cellular factors among γ-IFN-induced, endosome-localized proteins inhibit MLV replication. We found that γ-IFN-inducible lysosomal thiolreductase (GILT) significantly restricts HIV-1 replication as well as MLV replication by its thiolreductase activity. GILT silencing enhanced replication-defective HIV-1 vector infection and virion production in γ-IFN-treated cells, although γ-IFN did not inhibit HIV-1 replication. This result showed that GILT is required for the anti-viral activity of γ-IFN. Interestingly, GILT protein level was increased by γ-IFN in uninfected cells and env-deleted HIV-1-infected cells, but not in full-length HIV-1-infected cells. γ-IFN-induced transcription from the γ-IFN-activation sequence was attenuated by the HIV-1 Env protein. These results suggested that the γ-IFN cannot restrict HIV-1 replication due to the inhibition of γ-IFN signaling by HIV-1 Env. Finally, we found that 4,4′-dithiodipyridine (4-PDS), which inhibits S-S bond formation at acidic pH, significantly suppresses HIV-1 vector infection and virion production, like GILT. In conclusion, this study showed that GILT functions as a host restriction factor against the retroviruses, and a GILT mimic, 4-PDS, is the leading compound for the development of novel concept of anti-viral agents.

Disulfide bond based polymeric drug carriers for cancer chemotherapy and relevant redox environments in mammals

Increasing numbers of disulfide linkage-employing polymeric drug carriers that utilize the reversible peculiarity of this unique covalent bond have been reported. The reduction-sensitive disulfide bond is usually employed as a linkage between hydrophilic and hydrophobic polymers, polymers and drugs, or as cross-linkers in polymeric drug carriers. These polymeric drug carriers are designed to exploit the significant redox potential difference between the reducing intracellular environments and relatively oxidizing extracellular spaces. In addition, these drug carriers can release a considerable amount of anticancer drug in response to the reducing environment when they reach tumor tissues, effectively improving antitumor efficacy. This review focuses on various disulfide linkage-employing polymeric drug carriers. Important redox thiol pools, including GSH/GSSG, Cys/CySS, and Trx1, as well as redox environments in mammals, will be introduced.

Aging, inflammation, immunity and periodontal disease

The increased prevalence and severity of periodontal disease have long been associated with aging, such that this oral condition affects the majority of the adult population over 50 years of age. Although the immune system is a critical component for maintaining health, aging can be characterized by quantitative and qualitative modifications of the immune system. This process, termed 'immunosenescence', is a progressive modification of the immune system that leads to greater susceptibility to infections, neoplasia and autoimmunity, presumably reflecting the prolonged antigenic stimulation and/or stress responses that occur across the lifespan. Interestingly, the global reduction in the host capability to respond effectively to these challenges is coupled with a progressive increase in the general proinflammatory status, termed 'inflammaging'. Consistent with the definition of immunosenescence, it has been suggested that the cumulative effect of prolonged exposure of the periodontium to microbial challenge is, at least in part, a contributor to the effects of aging on these tissues. Thus, it has also been hypothesized that alterations in the function of resident immune and nonimmune cells of the periodontium contribute to the expression of inflammaging in periodontal disease. Although the majority of aging research has focused on the adaptive immune response, it is becoming increasingly clear that the innate immune compartment is also highly affected by aging. Thus, the phenomenon of immunosenescence and inflammaging, expressed as age-associated changes within the periodontium, needs to be more fully understood in this era of precision and personalized medicine and dentistry.

Immune response of interferon-γ-inducible lysosomal thiol reductase (GILT) from Chinese sturgeon (Acipenser sinensis) to microbial invasion and its antioxdative activity in lipopolysaccharides-treated mammalian dentritic cells

Interferon-γ-inducible lysosomal thiol reductase (GILT) plays an important role in the major histocompatibility complex-restricted antigen processing of endocytosed proteins via catalyzing the disulfide bond reduction in the endocytic pathway. Here, the cDNA of Chinese sturgeon (Acipenser sinensis) GILT (CsGILT) was cloned. It contained an open reading frame of 762 nucleotides encoding a protein of 254 amino acids with an estimated molecular weight of 28.1 kDa. The characteristic structural features, including a signature sequence CQHGX2ECX2NX4C, a CXXC motif, two potential N-glycosylation sites, and eight conserved cysteines were detected in the deduced amino acid sequence of CsGILT. CsGILT was widely expressed in Chinese sturgeon with the highest expression in the spleen, and CsGILT mRNA expression was significantly up-regulated when Chinese sturgeons were challenged with polyinosinic polycytidylic acid or Vibrio anguillarum. The recombinant CsGILT displayed obvious thiol reductase activity demonstrated by catalyzing the reduction of mouse IgG(H+L) by dithiothreitol into heavy chain and light chain. CsGILT also displayed significant antioxidant activity in mouse dentritic cells as indicated by its increasing GSH level and GSH/GSSG ratio, decreasing intracellular reactive oxygen species and nitric oxide levels and lipid peroxidation, as well as enhancing the activities of the antioxidative redox enzymes including catalase and superoxide dismutase. Our results suggested an important role for CsGILT in the immune response in Chinese sturgeon to pathogen invasion possibly via a conserved functional mechanism throughout vertebrate evolution, contributing to our understanding the immune biology and protection of Chinese sturgeon.

Protein structure shapes immunodominance in the CD4 T cell response to yellow fever vaccination

The live attenuated yellow fever (YF) vaccine is a highly effective human vaccine and induces long-term protective neutralizing antibodies directed against the viral envelope protein E. The generation of such antibodies requires the help of CD4 T cells which recognize peptides derived from proteins in virus particles internalized and processed by E-specific B cells. The CD4 T helper cell response is restricted to few immunodominant epitopes, but the mechanisms of their selection are largely unknown. Here, we report that CD4 T cell responses elicited by the YF-17D vaccine are focused to hotspots of two helices of the viral capsid protein and to exposed strands and loops of E. We found that the locations of immunodominant epitopes within three-dimensional protein structures exhibit a high degree of overlap between YF virus and the structurally homologous flavivirus tick-borne encephalitis virus, although amino acid sequence identity of the epitope regions is only 15-45%. The restriction of epitopes to exposed E protein surfaces and their strikingly similar positioning within proteins of distantly related flaviviruses are consistent with a strong influence of protein structure that shapes CD4 T cell responses and provide leads for a rational design of immunogens for vaccination.