Absence of gamma-interferon-inducible lysosomal thiol reductase in melanomas disrupts T cell recognition of select immunodominant epitopes

Induction of Neural Differentiation and Protection by a Novel Slow-Release Nanoparticle Estrogen Construct in a Rat Model of Spinal Cord Injury

Spinal cord injury (SCI) is a complex debilitating condition leading to permanent life-long neurological deficits. Estrogen (E2) treatment is known to be neuroprotectant in SCI. This hormone is highly pleiotropic and has been shown to decrease apoptosis, modulate calcium signaling, regulate growth factor expression, act as an anti-inflammatory, and drive angiogenesis. These beneficial effects were found in our earlier study at the low dose of 10 µg/kg E2 in rats. However, the dose remains non-physiologic, which poses a safety hurdle for clinical use. Thus, we recently devised/constructed a fast release nanoparticle (NP) estrogen embedded (FNP-E2) construct and tested a focal delivery system in a contused SCI rat model which showed protection in the short run. In the current study, we have developed a novel slow-release NP estrogen (SNP-E2) delivery system that shows sustained release of E2 in the injured spinal cord and no systemic exposure in the host. The study of E2 release and kinetics of this SNP-E2 construct in vitro and in vivo supported this claim. Delivery of E2 to the injured spinal cord via this approach reduced inflammation and gliosis, and induced microglial differentiation of M1 to M2 in rats after SCI. Analysis of spinal cord samples showed improved myelination and survival signals (AKT) as demonstrated by western blot analysis. SNP-E2 treatment also induced astrocytic differentiation into neuron-like (MAP2/NeuN) cells, supported the survival of oligodendrocyte precursor cells (OPC), and improved bladder and locomotor function in rats following SCI. These data suggest that this novel delivery strategy of SNP-E2 to the injured spinal cord may provide a safe and effective therapeutic approach to treat individuals suffering from SCI.

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.

Comprehensive analysis of the role of interferon gamma-inducible protein 30 on immune infiltration and prognosis in clear cell renal cell carcinoma

Although the immune factor interferon gamma-inducible protein 30 (IFI30) has been linked to the growth and immune infiltration of various malignancies, its function and mechanism in clear cell renal cell carcinoma (ccRCC) remains unclear. We used several databases to detect and validate IFI30 expression in ccRCC and its connection to immune invasion. We found that IFI30 expression was higher in ccRCC tissues compared to normal tissues, and was strongly associated with tumor grade, T stage, and M stage. Univariate and multivariate analyses showed that ccRCC cases with lower IFI30 expression levels had a higher OS rate than those with high IFI30 expression (P < 0.05). Additionally, we collected a total of 104 cases of ccRCC and adjacent tissues from the First Affiliated Hospital of Jinzhou Medical University between January 2018 and January 2020 for immunohistochemical (IHC) analysis, along with their relevant clinicopathological data. The relationship between IFI30 and expression of CD3E, CD4, CD8A, interleukin 10 (IL-10) and transforming growth factor beta (TGFB2) was examined using the ccRCC data from The Cancer Genome Atlas (TCGA) database, with findings verified by IHC analysis using the collected cases. Statistical analysis performed with SPSS found the positive correlation between the expression of CD3E, CD4, CD8A and IL-10 and the IFI30 expression, and negative correlation of TGFB2 expression with the IFI30 expression in ccRCC. Concurrently, a notable association was observed between high IFI30 expression and immune cell infiltration in ccRCC. High IFI30 expression is connected to the ccRCC's poor prognosis with the infiltration of immune cell. These findings suggest that high IFI30 expression could serve as a marker of poor prognosis and be associated with immune cell infiltration in ccRCC.

Major histocompatibility complex class II in the tumor microenvironment: functions of nonprofessional antigen-presenting cells

Major histocompatibility complex class-II-restricted presentation by nonprofessional antigen-presenting cells in the tumor microenvironment can regulate antitumor T-cell responses. In murine models, tumor cell-specific MHC class II expression decreases in vivo tumor growth, dependent on T cells. Tumor cell-specific MHC class II expression is associated with improved survival and response to immune checkpoint inhibitors in human cancers. Antigen-presenting cancer-associated fibroblasts (apCAF) present MHC class-II-restricted antigens and activate CD4 T cells. The role of MHC class II on apCAFs depends on the cell of origin. MHC class II on tumoral lymphatic endothelial cells leads to expansion of regulatory T cells and increased in vivo tumor growth.

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.

Peptide Modification Diminishes HLA Class II-restricted CD4+ T Cell Recognition of Prostate Cancer Cells

Prostate cancer poses an ongoing problem in the western world accounting for significant morbidity and mortality in the male population. Current therapy options are effective in treating most prostate cancer patients, but a significant number of patients progress beyond a manageable disease. For these patients, immunotherapy has emerged as a real option in the treatment of the late-stage metastatic disease. Unfortunately, even the most successful immunotherapy strategies have only led to a four-month increase in survival. One issue responsible for the shortcomings in cancer immunotherapy is the inability to stimulate helper CD4⁺ T cells via the HLA class II pathway to generate a potent antitumor response. Obstacles to proper HLA class II stimulation in prostate cancer vaccine design include the lack of detectable class II proteins in prostate tumors and the absence of defined class II specific prostate tumor antigens. Here, for the first time, we show that the insertion of a lysosomal thiol reductase (GILT) into prostate cancer cells directly enhances HLA class II antigen processing and results in increased CD4⁺ T cell activation by prostate cancer cells. We also show that GILT insertion does not alter the expression of prostate-specific membrane antigen (PSMA), an important target in prostate cancer vaccine strategies. Our study suggests that GILT expression enhances the presentation of the immunodominant PSMA₄₅₉ epitope via the HLA class II pathway. Biochemical analysis showed that the PSMA₄₅₉ peptide was cysteinylated under a normal physiologic concentration of cystine, and this cysteinylated form of PSMA₄₅₉ inhibited T cell activation. Taken together, these results suggest that GILT has the potential to increase HLA class II Ag presentation and CD4⁺ T cell recognition of prostate cancer cells, and GILT-expressing prostate cancer cells could be used in designing cell therapy and/or vaccines against prostate cancer.

Human leukocyte antigen Class II alleles associated with acral lentiginous melanoma in Mexican Mestizo patients: A case-control study

Background Melanoma is an aggressive cutaneous cancer. Acral lentiginous melanoma is a melanoma subtype arising on palms, soles, and nail-units. The incidence, prevalence and prognosis differ among populations. The link between expression of major histocompatibility complex Class II alleles and melanoma progression is known. However, available studies report variable results regarding the association of melanoma with specific HLA Class II loci. Aims The aim of the study was to determine HLA Class II allele frequencies in acral lentiginous melanoma patients and healthy Mexican Mestizo individuals. Methods Eighteen patients with acral lentiginous melanoma and 99 healthy controls were recruited. HLA Class II typing was performed based on the sequence-specific oligonucleotide method. Results Three alleles were associated with increased susceptibility to develop acral lentiginous melanoma, namely: HLA-DRB1*13:01; pC = 0.02, odds ratio = 6.1, IC95% = 1.4-25.5, HLA-DQA1*01:03; pC = 0.001, odds ratio = 9.3, IC95% = 2.7-31.3 and HLA-DQB1*02:02; pC = 0.01, odds ratio = 3.7, IC95% = 1.4-10.3. Limitations The small sample size was a major limitation, although it included all acral lentiginous melanoma patients seen at the dermatology department of Dr. Manuel Gea González General Hospital during the study period. Conclusion HLA-DRB1*13:01, HLA-DQB1*02:02 and HLA-DQA*01:03 alleles are associated with increased susceptibility to develop acral lentiginous melanoma in Mexican Mestizo patients.

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.

GILT Expression in Human Melanoma Cells Enhances Generation of Antigenic Peptides for HLA Class II-Mediated Immune Recognition

Melanoma is an aggressive skin cancer that has become increasingly prevalent in western populations. Current treatments such as surgery, chemotherapy, and high-dose radiation have had limited success, often failing to treat late stage, metastatic melanoma. Alternative strategies such as immunotherapies have been successful in treating a small percentage of patients with metastatic disease, although these treatments to date have not been proven to enhance overall survival. Several melanoma antigens (Ags) proposed as targets for immunotherapeutics include tyrosinase, NY-ESO-1, gp-100, and Mart-1, all of which contain both human leukocyte antigen (HLA) class I and class II-restricted epitopes necessary for immune recognition. We have previously shown that an enzyme, gamma-IFN-inducible lysosomal thiol-reductase (GILT), is abundantly expressed in professional Ag presenting cells (APCs), but absent or expressed at greatly reduced levels in many human melanomas. In the current study, we report that increased GILT expression generates a greater pool of antigenic peptides in melanoma cells for enhanced CD4+ T cell recognition. Our results suggest that the induction of GILT in human melanoma cells could aid in the development of a novel whole-cell vaccine for the enhancement of immune recognition of metastatic melanoma.

Protective Effects of Estrogen via Nanoparticle Delivery to Attenuate Myelin Loss and Neuronal Death after Spinal Cord Injury

Spinal cord injury (SCI) is associated with devastating neurological deficits affecting more than 11,000 Americans each year. Although several therapeutic agents have been proposed and tested, no FDA-approved pharmacotherapy is available for SCI treatment. We have recently demonstrated that estrogen (E2) acts as an antioxidant and anti-inflammatory agent, attenuating gliosis in SCI. We have also demonstrated that nanoparticle-mediated focal delivery of E2 to the injured spinal cord decreases lesion size, reactive gliosis, and glial scar formation. The current study tested in vitro effects of E2 on reactive oxygen species (ROS) and calpain activity in microglia, astroglia, macrophages, and fibroblasts, which are believed to participate in the inflammatory events and glial scar formation after SCI. E2 treatment decreased ROS production and calpain activity in these glial cells, macrophages, and fibroblast cells in vitro. This study also tested the efficacy of fast- and slow-release nanoparticle-E2 constructs in a rat model of SCI. Focal delivery of E2 via nanoparticles increased tissue distribution of E2 over time, attenuated cell death, and improved myelin preservation in injured spinal cord. Specifically, the fast-release nanoparticle-E2 construct reduced the Bax/Bcl-2 ratio in injured spinal cord tissues, and the slow-release nanoparticle-E2 construct prevented gliosis and penumbral demyelination distal to the lesion site. These data suggest this novel E2 delivery strategy to the lesion site may decrease inflammation and improve functional outcomes following SCI.

Prognostic value of gamma-interferon-inducible lysosomal thiol reductase expression in female patients diagnosed with breast cancer

Because of the high heterogeneity of breast cancer outcome, identification of novel prognostic biomarkers is critical to improve patient stratification and guide precise treatment. We examined the prognostic value of gamma-interferon-inducible lysosomal thiol reductase (GILT) expression in a training set of 416 breast cancer patients and a validation set of 210 patients, and performed functional studies to investigate the functions and underlying mechanisms of GILT on breast cancer prognosis. Our results indicated that high GILT expression in breast cancer cells was associated with improved disease-free survival (DFS; hazard ratio [HR] = 0.189, 95% confidence interval [CI]: 0.099-0.361) and breast cancer-specific survival (BCSS; HR = 0.187, 95% CI: 0.080-0.437) of breast cancer patients both in the training set and the external validation set (HR = 0.453, 95% CI: 0.235-0.873 for DFS, HR = 0.488, 95% CI: 0.245-0.970 for BCSS). In vitro and in vivo studies showed that GILT overexpression inhibited breast cancer cells proliferation, invasion, migration and tumor formation in nude mice and increased sensitivity of breast cancer cells to standard treatment. Proteomics analysis indicated that GILT inhibited reactive oxygen species (ROS) and autophagy activation in breast cancer cells, and GILT overexpression-mediated tumor growth was further enhanced in the presence of autophagy or ROS inhibitors. Our results demonstrate that GILT expression can be effectively used to predict the prognosis and guide treatment strategies of breast cancer patients.

Expression of gilt acts as a positive regulator of mouse hematopoietic progenitor cells

Gamma interferon inducible lysosomal thiol reductase (GILT), is known to be involved in immunity, but its role in hematopoiesis has not been previously reported. Herein, we demonstrate using gilt knockout (-/-) mice that loss of gilt associates with decreased numbers and cycling status of femoral hematopoietic progenitor cells (CFU-GM, BFU-E, and CFU-GEMM) with more modest effects on splenic progenitor cells. Thus, GILT is associated with positive regulation of hematopoietic progenitor cells in mice, mainly in bone marrow.

GILT in tumor cells improves T cell-mediated anti-tumor immune surveillance

The lysosomal thiol reductase GILT catalyzes the reduction of disulfide bonds of protein antigens, facilitating antigen-presenting cells (APCs) to present antigen to T cells. However, whether GILT expression in tumor cells can be associated with improved T cell-mediated anti-tumor responses remains unknown. Here, we identify that GILT is able to facilitate anti-tumor immune surveillance via promoting MHC class I mediated-antigen presentation in colon carcinoma. By using mice model bearing colon tumors, we find that GILT inhibites tumor growth in vivo with more leucocytes infiltration but has no effect on tumor cell development in vitro in terms of proliferation, cell cycle and migration. Furthermore, by using transgenic OT-I mice, we recognize the tumor-expressing OVA peptide, a surrogate tumor antigen, we find that GILT is capable of enhancing MHC class I mediated antigen presentation and improving specific CD8⁺ T cell anti-tumor responses in murine colon carcinoma. These findings propose the boost of GILT-MHC-I axis in tumors as a viable option for immune system against cancer.

A non-immunological role for γ-interferon-inducible lysosomal thiol reductase (GILT) in osteoclastic bone resorption

The extracellular bone resorbing lacuna of the osteoclast shares many characteristics with the degradative lysosome of antigen-presenting cells. γ-Interferon-inducible lysosomal thiol reductase (GILT) enhances antigen processing within lysosomes through direct reduction of antigen disulfides and maintenance of cysteine protease activity. In this study, we found the osteoclastogenic cytokine RANKL drove expression of GILT in osteoclast precursors in a STAT1-dependent manner, resulting in high levels of GILT in mature osteoclasts, which could be further augmented by γ-interferon. GILT colocalized with the collagen-degrading cysteine protease, cathepsin K, suggesting a role for GILT inside the osteoclastic resorption lacuna. GILT-deficient osteoclasts had reduced bone-resorbing capacity, resulting in impaired bone turnover and an osteopetrotic phenotype in GILT-deficient mice. We demonstrated that GILT could directly reduce the noncollagenous bone matrix protein SPARC, and additionally, enhance collagen degradation by cathepsin K. Together, this work describes a previously unidentified, non-immunological role for GILT in osteoclast-mediated bone resorption.

The association of genetic variants IL2RA rs2104286, IFI30 rs11554159 and IKZF3 rs12946510 with multiple sclerosis onset and severity in patients from Serbia

An algorithm Probabilistic Identification of Causal SNPs, identified 434 causal variants for multiple sclerosis (MS) including IL2RA rs2104286, IFI30 rs11554159 and IKZF3 rs12946510. Analysis of individual and combined effects of these variants in the Serbian population identified that Il2RA rs2104286 G allele carriers had a lower risk for developing MS (gender adjusted OR = 0.63, p = .003). With regard to the IFI30 rs11554159 recessive genetic model, among HLA-DRB1*15:01 positive patients, the AA homozygote had a significantly higher MSSS compared to the G allele carriers (p = .003). This study confirms role of IL2RA rs2104286 in MS and suggest the role of IFI30 rs11554159 in disease severity, which needs validation.

IFI30 expression is an independent unfavourable prognostic factor in glioma

Gamma-interferon-inducible lysosomal thiol reductase, the only known lysosomal thiol reductase, is encoded by gene IFI30 and expressed constitutively in antigen-presenting cells. Our comprehensive study on IFI30 in gliomas found its expression to be high in glioblastomas and in gliomas with a mesenchymal subtype or wild-type isocitrate dehydrogenase, all of which indicated the malignancy and poor outcomes of gliomas. Kaplan-Meier survival analysis ascertained that high IFI30 expression conferred poor outcomes. The IFI30 expression levels also showed high efficiency in predicting 1-, 3- and 5-year overall survival. Univariable and multivariable Cox regression analyses were performed to define IFI30 as an independent prognostic marker. Biological process analysis suggested that IFI30 was involved in immune responses. ESTIMATE and CIBERSORT were applied to evaluate immune cell infiltration, with results indicating that samples with higher IFI30 expression had higher infiltration of immune cells, including regulatory T cells and M0 macrophages. Correlation analysis showed that IFI30 was significantly positively correlated with immune checkpoints that suppress effective antitumour immune responses. Immunohistochemical staining was also performed to confirm the association between IFI30 expression and the immune phenotype. The suggested correlation between high IFI30 expression and an immunosuppressive phenotype contributes to our knowledge about the glioma microenvironment and might provide clues for the development of novel therapeutic targets.

Inhibition of acid ceramidase regulates MHC class II antigen presentation and suppression of autoimmune arthritis

The bioactive sphingolipid ceramide affects immune responses although its effect on antigen (Ag) processing and delivery by HLA class II to CD4+T-cells remains unclear. Therefore, we examined the actions of a novel cell-permeable acid ceramidase (AC) inhibitor [(1R,2R) N myristoylamino-(4'-nitrophenyl)-propandiol-1,3] on antigen presentation and inflammatory cytokine production by Ag-presenting cells (APCs) such as B-cells, macrophages, and dendritic cells. We found that AC inhibition in APCs perturbed Ag-processing and presentation via HLA-DR4 (MHC class II) proteins as measured by coculture assay and T-cell production of IL-2. Mass spectral analyses showed that B13 treatment significantly raised levels of four types of ceramides in human B-cells. B13 treatment did not alter Ag internalization and class II protein expression, but significantly inhibited lysosomal cysteinyl cathepsins (B, S and L) and thiol-reductase (GILT), HLA class II Ag-processing, and generation of functional class II-peptide complexes. Ex vivo Ag presentation assays showed that inhibition of AC impaired primary and recall CD4+T-cell responses and cytokine production in response against type II collagen. Further, B13 delayed onset and reduced severity of inflamed joints and cytokine production in the collagen-induced arthritis mouse model in vivo. These findings suggest that inhibition of AC in APCs may dysregulate endolysosomal proteases and HLA class II-associated self-antigen presentation to CD4+T-cells, attenuating inflammatory cytokine production and suppressing host autoimmune responses.

Enolase inhibition alters metabolic hormones and inflammatory factors to promote neuroprotection in spinal cord injury

Enolase inhibition is a potential therapeutic strategy currently being investigated for treatment of spinal cord injury (SCI) as it reduces pro-inflammatory cytokines and chemokines, alters metabolic factors, and reduces gliosis in acute SCI. Herein, the role of enolase in SCI has been examined to better understand the effects of this enzyme on inflammation, metabolic hormones, glial cell activation, and neuroprotection under these shorter injury conditions. Immunohistochemical analyses of inflammatory markers vimentin, Cox-2, and caspase-1 indicated that enolase inhibition attenuated the elevated levels of inflammation seen following SCI. Iba1, GFAP, NFP, and CSPG staining indicated that enolase inhibition with prolonged administration of ENOblock reduced microglia/astrocyte activation and lead to enhanced neuroprotection in SCI. An analysis of metabolic hormones revealed that ENOblock treatment significantly upregulated plasma concentrations of peptide YY, glucagon-like peptide 1, glucose-dependent insulinotropic peptide, glucagon, and insulin hormones as compared to vehicle-treated controls (Mann-Whitney, p ≤ 0.05). ENOblock did not have a significant effect on plasma concentrations of pancreatic polypeptide. Interestingly, ENOblock treatment inhibited chondroitin sulfate proteoglycan (CSPG), which is produced by activated glia and serves to block regrowth of axons across the lesion site following injury. An increased level of NeuN and MBP with reduced caspase-1 was detected in SCI tissues after ENOblock treatment, suggesting preservation of myelin and induction of neuroprotection. ENOblock also induced improved motor function in SCI rats, indicating a role for enolase in modulating inflammatory and metabolic factors in SCI with important implications for clinical consideration.

GILT in Thymic Epithelial Cells Facilitates Central CD4 T Cell Tolerance to a Tissue-Restricted, Melanoma-Associated Self-Antigen

Central tolerance prevents autoimmunity, but also limits T cell responses to potentially immunodominant tumor epitopes with limited expression in healthy tissues. In peripheral APCs, γ-IFN-inducible lysosomal thiol reductase (GILT) is critical for MHC class II-restricted presentation of disulfide bond-containing proteins, including the self-antigen and melanoma Ag tyrosinase-related protein 1 (TRP1). The role of GILT in thymic Ag processing and generation of central tolerance has not been investigated. We found that GILT enhanced the negative selection of TRP1-specific thymocytes in mice. GILT expression was enriched in thymic APCs capable of mediating deletion, namely medullary thymic epithelial cells (mTECs) and dendritic cells, whereas TRP1 expression was restricted solely to mTECs. GILT facilitated MHC class II-restricted presentation of endogenous TRP1 by pooled thymic APCs. Using bone marrow chimeras, GILT expression in thymic epithelial cells (TECs), but not hematopoietic cells, was sufficient for complete deletion of TRP1-specific thymocytes. An increased frequency of TRP1-specific regulatory T (Treg) cells was present in chimeras with increased deletion of TRP1-specific thymocytes. Only chimeras that lacked GILT in both TECs and hematopoietic cells had a high conventional T/Treg cell ratio and were protected from melanoma challenge. Thus, GILT expression in thymic APCs, and mTECs in particular, preferentially facilitates MHC class II-restricted presentation, negative selection, and increased Treg cells, resulting in a diminished antitumor response to a tissue-restricted, melanoma-associated self-antigen.

Integrated transcriptomic and proteomic analyses of grass carp intestines after vaccination with a double-targeted DNA vaccine of Vibrio mimicus

Intestinal mucosal immunity plays a vital role against Vibrio mimicus infection because it is an enteric pathogen causing serious vibriosis in fish. In the previous studies, we developed an oral double-targeted DNA vaccine of V. mimicus and demonstrated that the vaccine could elicit significantly higher intestinal mucosal immune response than did naked DNA vaccine. But, little is known underlying regulatory molecular mechanisms of the enhanced intestinal mucosal immunity. Here the transcriptome and proteome in the intestines of the grass carps immunized or not with the double-targeted DNA vaccine were investigated by using RNA-seq and iTRAQ-coupled LC-MS/MS. Compared with the control group, a total of 5339 differentially expressed genes (DEGs) and 1173 differentially expressed proteins (DEPs) were identified in the immunized fish intestines. Subsequently, the integrated analysis between transcriptome and proteome data revealed that 250 DEPs were matched with the corresponding DEGs (named associated DEPs/DEGs) at both transcriptome and proteome levels. Fifty of all the associated DEPs/DEGs were immune-related and mainly enriched in phagosome, antigen-processing and presentation, complement and coagulation cascades, NLRs and MAPK signaling pathways via Gene Ontology and KEGG pathway analyses, which suggested the coordination of the five activated pathways was essential to the enhanced intestinal mucosal immune response in the immunized fish. The protein-protein interaction analysis showed that 60 of the 63 immune-related DEPs to form an integrated network. Additionally, randomly selected DEGs and DEPs were respectively validated by quantitative real-time RT-PCR and multiple reaction monitoring (MRM) assay, indicating that the both RNA-Seq and iTRAQ results in the study were reliable. Overall, our comprehensive transcriptome and proteome data provide some key genes and their protein products for further research on the regulatory molecular mechanisms underlying the enhanced intestinal mucosal immunity.

IFI30 Is a Novel Immune-Related Target with Predicting Value of Prognosis and Treatment Response in Glioblastoma

Purpose

As a crucial part of anti-tumor immunotherapy, interferon-α/β (IFN-α/β) treatment has been broadly applied to clinical trials of glioma. However, less is known about implement of interferon-γ (IFN-γ) in glioma. Further investigating the valuable hub molecular of IFN-γ family might provide us a novel guidance for glioma therapy.

Methods

This study carried out an analysis on glioma patients from the Chinese Glioma Genome Atlas (CGGA) and The Cancer Genome Atlas (TCGA) cohorts. The analyses were performed by GraphPad Prism 8 and R language. All the validated experiments were performed three times independently.

Results

We identified IFI30 as the most stable independent prognostic gene among 20 classical IFN-γ stimulated genes (ISGs) in glioma patients. Furthermore, we found that IFI30 highly expressed in malignant subtypes of glioma and associated with chemotherapy response. We also found IFI30 could activate IL6-STAT6 signal pathway to decline the glioma cells' chemotherapy sensitivity by performing experiments. Gene ontology (GO) analysis showed IFI30 associated with enhanced leucocyte mediated immune and inflammatory response. Microenvironment analysis referred that high IFI30 expression accompanied with more infiltration of M2 type macrophages.

Conclusion

IFI30 is involved in the malignant progression and chemotherapy response of glioblastoma, which can be a potential target for treatment in glioblastoma patients.

High GILT Expression and an Active and Intact MHC Class II Antigen Presentation Pathway Are Associated with Improved Survival in Melanoma

The MHC class I Ag presentation pathway in melanoma cells has a well-established role in immune-mediated destruction of tumors. However, the clinical significance of the MHC class II Ag presentation pathway in melanoma cells is less clear. In Ag-presenting cells, IFN-γ-inducible lysosomal thiol reductase (GILT) is critical for MHC class II-restricted presentation of multiple melanoma Ags. Although not expressed in benign melanocytes of nevi, GILT and MHC class II expression is induced in malignant melanocytes in a portion of melanoma specimens. Analysis of The Cancer Genome Atlas cutaneous melanoma data set showed that high GILT mRNA expression was associated with improved overall survival. Expression of IFN-γ, TNF-α, and IL-1β was positively associated with GILT expression in melanoma specimens. These cytokines were capable of inducing GILT expression in human melanoma cells in vitro. GILT protein expression in melanocytes was induced in halo nevi, which are nevi undergoing immune-mediated regression, and is consistent with the association of GILT expression with improved survival in melanoma. To explore potential mechanisms of GILT's association with patient outcome, we investigated pathways related to GILT function and expression. In contrast to healthy skin specimens, in which the MHC class II pathway was nearly uniformly expressed and intact, there was substantial variation in the MHC class II pathway in the The Cancer Genome Atlas melanoma specimens. Both an active and intact MHC class II pathway were associated with improved overall survival in melanoma. These studies support a role for GILT and the MHC class II Ag presentation pathway in melanoma outcome.

Penaeus monodon GILT enzyme restricts WSSV infectivity by reducing disulfide bonds in WSSV proteins

Gamma-interferon-inducible lysosomal thiol reductase (GILT) is involved in the adaptive immune response via its effects on major histocompatibility complex (MHC)-restricted antigen presentation. In addition to antigen presentation, GILT exerts its antiviral activity by reducing disulfide bonds in proteins involved in viral infection and assembly, thereby inhibiting viral envelope-mediated infection and viral progeny production. In black tiger shrimp, Penaeus monodon GILT (PmGILT) was cloned and characterized, and found to be involved in the shrimp innate immune response and to exert neutralizing activity against white spot syndrome virus (WSSV) infection. However, the anti-WSSV mechanism of PmGILT in the shrimp innate immune response has not been defined. To explore the anti-WSSV activity of PmGILT, a yeast 2-hybrid (Y2H) assay was performed to identify WSSV proteins targeted by PmGILT. The assay revealed 4 potential PmGILT-interacting WSSV proteins: WSSV002, WSSV164, WSSV189, and WSSV471. Three of these 4 WSSV proteins (WSSV002, WSSV164 and WSSV189) were successfully produced and confirmed to interact with PmGILT in in vitro pull-down assays. WSSV189 and WSSV471 were previously identified as structural proteins, whereas WSSV164 is an immediate-early protein which has anti-melanization activity, and WSSV002 is an unknown. Because of the thiol reductase activity of PmGILT, WSSV164 and WSSV189, both of which are cysteine-containing WSSV proteins, were chosen for disulfide bond reduction assays. PmGILT reduced intrachain disulfide bonds in both WSSV proteins, suggesting that PmGILT exerts its anti-WSSV activity via its thiol reductase activity to disrupt the WSSV protein complex and restore the melanization activity of PmproPO1 and PmproPO2.

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.

Lentivirus mediated γ-interferon-inducible lysosomal thiol reductase (GILT) knockdown suppresses human glioma U373MG cell proliferation

BACKGROUND

Glioma is the most common malignancy in brain carcinoma with poor prognosis due to the lack of understanding of the mechanism underlying the disease. γ-interferon-inducible lysosomal thiol reductase (GILT) plays a critical role in the process of antigen processing. However, the role of GILT in the tumorigenesis of glioma remains unknown.

MATERIALS AND METHODS

The expression of GILT was analyzed by bioinformatics using the public database and by qPCR in three human glioma cell lines. Cell growth and viability were determined by Celigo and MTT assays, while cell cycle arrest and apoptosis were determined using flow cytometry. Giemsa staining was used to analyze the colony formation, while cell motility was assessed using transwell migration and invasion assays, as well as, using tumor growth in nude mice.

RESULTS

GILT was highly expressed as observed in the public database on human gliomas and two human glioma cell lines, U373MG and U87MG cells. The downregulation of GILT by lentiviral-mediated silencing inhibits the cell growth, colony formation, and migration but promotes apoptosis and results in cell cycle arrest at the G0/G1 phase in the U373MG cells. Also, the knockdown of GILT inhibits tumor growth in vivo.

CONCLUSION

Elevated GILT is positively associated with glioma progression. GILT silencing suppresses cell proliferation, colony formation, migration, and tumor growth, and induces apoptosis and cell cycle arrest. GILT may serve as a potential target for the treatment of glioma.

Endoplasmic reticulum stress, autophagic and apoptotic cell death, and immune activation by a natural triterpenoid in human prostate cancer cells

Though the current therapies are effective at clearing an early stage prostate cancer, they often fail to treat late-stage metastatic disease. We aimed to investigate the molecular mechanisms underlying the anticancer effects of a natural triterpenoid, ganoderic acid DM (GA-DM), on two human prostate cancer cell lines: the androgen-independent prostate carcinoma (PC-3), and androgen-sensitive prostate adenocarcinoma (LNCaP). Cell viability assay showed that GA-DM was relatively more toxic to LNCaP cells than to PC-3 cells (IC₅₀ s ranged 45-55 µM for PC-3, and 20-25 µM for LNCaP), which may have occurred due to differential expression of p53. Hoechst DNA staining confirmed detectable nuclear fragmentation in both cell lines irrespective of the p53 status. GA-DM treatment decreased Bcl-2 proteins while it upregulated apoptotic Bax and autophagic Beclin-1, Atg5, and LC-3 molecules, and caused an induction of both early and late events of apoptotic cell death. Biochemical analyses of GA-DM-treated prostate cancer cells demonstrated that caspase-3 cleavage was notable in GA-DM-treated PC-3 cells. Interestingly, GA-DM treatment altered cell cycle progression in the S phase with a significant growth arrest in the G2 checkpoint and enhanced CD4 ⁺ T cell recognition of prostate tumor cells. Mechanistic study of GA-DM-treated prostate cancer cells further demonstrated that calpain activation and endoplasmic reticulum stress contributed to cell death. These findings suggest that GA-DM is a candidate for future drug design for prostate cancer as it activates multiple pathways of cell death and immune recognition.

The phagosome and redox control of antigen processing

In addition to debris clearance and antimicrobial function, versatile organelles known as phagosomes play an essential role in the processing of exogenous antigen in antigen presenting cells. While there has been much attention on human leukocyte antigen haplotypes in the determination of antigenic peptide repertoires, the lumenal biochemistries within phagosomes and endosomes are emerging as equally-important determinants of peptide epitope composition and immunodominance. Recently, the lumenal redox microenvironment within these degradative compartments has been shown to impact two key antigenic processing chemistries: proteolysis by lysosomal cysteine proteases and disulfide reduction of protein antigens. Through manipulation of the balance between oxidative and reductive capacities in the phagosome-principally by modulating NADPH oxidase (NOX2) and γ-interferon-inducible lysosomal thiol reductase (GILT) activities-studies have demonstrated changes to antigen processing patterns leading to modified repertoires of antigenic peptides available for presentation, and subsequently, altered disease progression in T cell-driven autoimmunity. This review focuses on the mechanisms and consequences of redox-mediated phagosomal antigen processing, and the potential downstream implications to tolerance and autoimmunity.

Melanoma LAMP-2C Modulates Tumor Growth and Autophagy

Autophagy plays critical but diverse roles in cellular quality control and homeostasis potentially checking tumor development by removing mutated or damaged macromolecules, while conversely fostering tumor survival by supplying essential nutrients during cancer progression. This report documents a novel inhibitory role for a lysosome-associated membrane protein, LAMP-2C in modulating autophagy and melanoma cell growth in vitro and in vivo. Solid tumors such as melanomas encounter a variety of stresses in vivo including inflammatory cytokines produced by infiltrating lymphocytes directed at limiting tumor growth and spread. Here, we report that in response to the anti-tumor, pro-inflammatory cytokine interferon-gamma, melanoma cell expression of LAMP2C mRNA significantly increased. These results prompted an investigation of whether increased melanoma cell expression of LAMP-2C might represent a mechanism to control or limit human melanoma growth and survival. In this study, enhanced expression of human LAMP-2C in melanoma cells perturbed macroautophagy and chaperone-mediated autophagy in several human melanoma lines. In vitro analysis showed increasing LAMP-2C expression in a melanoma cell line, triggered reduced cellular LAMP-2A and LAMP-2B protein expression. Melanoma cells with enhanced LAMP-2C expression displayed increased cell cycle arrest, increased expression of the cell cycle regulators Chk1 and p21, and greater apoptosis and necrosis in several cell lines tested. The increased abundance of Chk1 protein in melanoma cells with increased LAMP-2C expression was not due to higher CHEK1 mRNA levels, but rather an increase in Chk1 protein abundance including Chk1 molecules phosphorylated at Ser345. Human melanoma cell xenografts with increased LAMP-2C expression, displayed reduced growth in immune compromised murine hosts. Melanomas with high LAMP-2C expression showed increased necrosis and reduced cell density upon histological analysis. These results reveal a novel role for LAMP-2C in negatively regulating melanoma growth and survival.

Anticancer Activity of Ganoderic Acid DM: Current Status and Future Perspective

Ganoderma lucidum is a mushroom that has a long history of medicinal use in the Far East countries as this mushroom is revered for its supposed miracle cures and life improving properties. Recently, this mushroom has come under scientific scrutiny to examine the possibility of finding biologically active compounds that may have an impact on human physiology. The main category of biologically active compounds produced in the G. lucidum, are the triterpenoids, which are known as Ganoderic Acids. In this review, we discuss one Ganoderic Acid in particular known as Ganoderic Acid-DM (GA-DM) that is extracted from the Ganoderma lucidum mushroom. We will discuss GA-DM as a potential therapeutic candidate for treating a number of diseases yet will focus on the potential to be used as an alternative or supplemental therapeutic agent in regards to various cancer types. The urge for this promising therapeutic agent is that GA-DM is capable of inducing cell death in cancer cells while exhibiting minimal toxicity to normal bystander cells. Furthermore, this review will look at GA-DM's ability to stimulate an immune response in the tumor environment to potentially provide long-term protection from the malignant tumors. We will also discuss the known routes of administration of GA-DM and pose the advantages and disadvantages of each route in a comparative manner. Finally, we will cover current status of the roles GA-DM may have as a therapeutic agent in respect to different cancer types as wells as discuss about its future perspective as a therapeutic candidate in other diseases as well.

Autophagy-dependent crosstalk between GILT and PAX-3 influences radiation sensitivity of human melanoma cells

Melanoma represents an ever-increasing problem in the western world as incidence rates continue to climb. Though manageable during early stages, late stage metastatic disease is highly resistant to current intervention. We have previously shown that gamma-interferon-inducible lysosomal thiol-reductase (GILT) enhances HLA class II antigen processing and immune detection of human melanoma cells. Here we report that GILT expression inhibits a potential target, paired box-3 (PAX-3) protein, in late stage human metastatic melanoma. We also show that GILT transfection or induction by IFN-γ, decreases PAX-3 protein expression while upregulating the expression of Daxx, which is also a repressor of PAX-3. Confocal microscopic analysis demonstrated that GILT co-localizes with PAX-3 protein, but not with Daxx within melanoma cells. Immunoprecipitation and immunoblotting studies suggest that GILT expression negatively regulates PAX-3 through the autophagy pathway, potentially resulting in increased susceptibility to conventional treatment in the form of chemotherapy or radiotherapy. While high-dose radiation is a common treatment for melanoma patients, our data suggest that GILT expression significantly increased the susceptibility of melanoma cells to low-dose radiation therapy via upregulation of tumor suppressor protein p53. Overall, these data suggest that GILT has multiple roles in inducing human melanoma cells as better targets for radiation and immunotherapy.

Targeting Enolase in Reducing Secondary Damage in Acute Spinal Cord Injury in Rats

Spinal cord injury (SCI) is a complex debilitating condition leading to permanent life-long neurological deficits. The complexity of SCI suggests that a concerted multi-targeted therapeutic approach is warranted to optimally improve function. Damage to spinal cord is complicated by an increased detrimental response from secondary injury factors mediated by activated glial cells and infiltrating macrophages. While elevation of enolase especially neuron specific enolase (NSE) in glial and neuronal cells is believed to trigger inflammatory cascades in acute SCI, alteration of NSE and its subsequent effects in acute SCI remains unknown. This study measured NSE expression levels and key inflammatory mediators after acute SCI and investigated the role of ENOblock, a novel small molecule inhibitor of enolase, in a male Sprague-Dawley (SD) rat SCI model. Serum NSE levels as well as cytokines/chemokines and metabolic factors were evaluated in injured animals following treatment with vehicle alone or ENOblock using Discovery assay. Spinal cord samples were also analyzed for NSE and MMPs 2 and 9 as well as glial markers by Western blotting. The results indicated a significant decrease in serum inflammatory cytokines/chemokines and NSE, alterations of metabolic factors and expression of MMPs in spinal cord tissues after treatment with ENOblock (100 µg/kg, twice). These results support the hypothesis that activation of glial cells and inflammation status can be modulated by regulation of NSE expression and activity. Analysis of SCI tissue samples by immunohistochemistry confirmed that ENOblock decreased gliosis which may have occurred through reduction of elevated NSE in rats. Overall, elevation of NSE is deleterious as it promotes extracellular degradation and production of inflammatory cytokines/chemokines and metabolic factors which activates glia and damages neurons. Thus, reduction of NSE by ENOblock may have potential therapeutic implications in acute SCI.

Interferon Gamma Prevents Infectious Entry of Human Papillomavirus 16 via an L2-Dependent Mechanism

In this study, we report that gamma interferon (IFN-γ) treatment, but not IFN-α, -β, or -λ treatment, dramatically decreased infection of human papillomavirus 16 (HPV16) pseudovirus (PsV). In a survey of 20 additional HPV and animal papillomavirus types, we found that many, but not all, PsV types were also inhibited by IFN-γ. Microscopic and biochemical analyses of HPV16 PsV determined that the antiviral effect was exerted at the level of endosomal processing of the incoming capsid and depended on the JAK2/STAT1 pathway. In contrast to infection in the absence of IFN-γ, where L1 proteolytic products are produced during endosomal capsid processing and L2/DNA complexes segregate from L1 in the late endosome and travel to the nucleus, IFN-γ treatment led to decreased L1 proteolysis and retention of L2 and the viral genome in the late endosome/lysosome. PsV sensitivity or resistance to IFN-γ treatment was mapped to the L2 protein, as determined with infectious hybrid PsV, in which the L1 protein was derived from an IFN-γ-sensitive HPV type and the L2 protein from an IFN-γ-insensitive type or vice versa.IMPORTANCE A subset of HPV are the causative agents of many human cancers, most notably cervical cancer. This work describes the inhibition of infection of multiple HPV types, including oncogenic types, by treatment with IFN-γ, an antiviral cytokine that is released from stimulated immune cells. Exposure of cells to IFN-γ has been shown to trigger the expression of proteins with broad antiviral effector functions, most of which act to prevent viral transcription or translation. Interestingly, in this study, we show that infection is blocked at the early step of virus entry into the host cell by retention of the minor capsid protein, L2, and the viral genome instead of trafficking into the nucleus. Thus, a novel antiviral mechanism for IFN-γ has been revealed.

Gamma-interferon-inducible lysosomal thiol reductase is upregulated in human melanoma

T-cell-mediated immunity has the ability to produce durable antimelanoma responses, resulting in improved survival of patients with advanced melanoma. Antigen presentation is a key determinant of T-cell responses. Gamma-interferon-inducible lysosomal thiol reductase (GILT) is critical for MHC class II-restricted presentation of multiple melanoma antigens to CD4+ T cells. However, GILT expression in melanoma has not been defined. We evaluated GILT and MHC class II expression in human primary and metastatic melanomas and nevi using immunohistochemical analysis. GILT staining in melanocytes was observed in 70% of primary and 58% of metastatic melanomas versus 0% of nevi. When present, the GILT staining intensity in melanocytes was typically faint. Both GILT and MHC class II expression were increased in melanocytes of primary and metastatic melanomas compared with nevi. GILT staining in antigen-presenting cells (APCs) was detected in 100% of primary and metastatic melanomas versus 31% of nevi, and it was typically intense. GILT expression was increased in APCs of primary and metastatic melanomas compared with nevi, whereas MHC class II had equivalent high expression in APCs of all melanocytic lesions. GILT staining in keratinocytes was detected in 67% of primary melanomas versus 14% of nevi and 6% of metastatic melanomas. GILT, but not MHC class II, expression was increased in keratinocytes of primary melanomas compared with nevi and metastases. GILT expression is anticipated to result in improved presentation of melanoma antigens and more effective antimelanoma T-cell responses. GILT expression may be a biomarker of immune recognition of melanoma.

Reduced immunogenicity of Plasmodium falciparum gamete surface antigen (Pfs48/45) in mice after disruption of disulphide bonds - evaluating effect of interferon-γ-inducible lysosomal thiol reductase

Sexual stages of Plasmodium are critical for malaria transmission and stage-specific antigens are important targets for development of malaria transmission-blocking vaccines. Plasmodium falciparum gamete surface antigen (Pfs48/45) is important for male gamete fertility and is being pursued as a candidate vaccine antigen. Vaccine-induced transmission-blocking antibodies recognize reduction-sensitive conformational epitopes in Pfs48/45. Processing and presentation of such disulphide-bond-constrained epitopes is critical for eliciting the desired immune responses. Mice lacking interferon-γ-inducible lysosomal thiol reductase (GILT), an enzyme that mediates reduction of S-S bonds during antigen processing, were employed to investigate immunogenicity of Pfs48/45. It has been well established that the ability to reduce S-S bonds in antigens guides effective T-cell immune responses; however, involvement of GILT in the induction of subsequent B-cell responses has not been explored. We hypothesized that the ability to reduce S-S bonds in Pfs48/45 will impact the generation of T-cell epitopes, and so influence helper T-cell responses required for specific B-cell responses. Non-reduced and reduced and alkylated forms of Pfs48/45 were employed to evaluate immune responses in wild-type and GILT knockout mice and studies revealed important differences in several immune response parameters, including differences in putative T-cell epitope recognition, faster kinetics of waning of Pfs48/45-specific IgG1 antibodies in knockout mice, differential patterns of interferon-γ and interleukin-4 secretions by splenocytes, and possible effects of GILT on induction of long-lived plasma cells and memory B cells responsible for antigen-recall responses. These studies emphasize the importance of antigen structural features that significantly influence the development of effective immune responses.

Reduction of myeloid-derived suppressor cells and lymphoma growth by a natural triterpenoid

Lymphoma is a potentially life threatening disease. The goal of this study was to investigate the therapeutic potential of a natural triterpenoid, Ganoderic acid A (GA-A) in controlling lymphoma growth both in vitro and in vivo. Here, we show that GA-A treatment induces caspase-dependent apoptotic cell death characterized by a dose-dependent increase in active caspases 9 and 3, up-regulation of pro-apoptotic BIM and BAX proteins, and a subsequent loss of mitochondrial membrane potential with release of cytochrome c. In addition to GA-A's anti-growth activity, we show that lower doses of GA-A enhance HLA class II-mediated antigen (Ag) presentation and CD4+ T cell recognition of lymphoma cells in vitro. The therapeutic relevance of GA-A treatment was also tested in vivo using the EL4 syngeneic mouse model of metastatic lymphoma. GA-A-treatment significantly prolonged survival of EL4 challenged mice and decreased tumor metastasis to the liver, an outcome accompanied by a marked down-regulation of STAT3 phosphorylation, reduction myeloid-derived suppressor cells (MDSCs), and enhancement of cytotoxic CD8+ T cells in the host. Thus, GA-A not only selectively induces apoptosis in lymphoma cells, but also enhances cell-mediated immune responses by attenuating MDSCs, and elevating Ag presentation and T cell recognition. The demonstrated therapeutic benefit indicates that GA-A is a candidate for future drug design for the treatment of lymphoma.

Endogenous and exogenous pathways maintain the reductive capacity of the phagosome

Although endosomes, lysosomes, and phagosomes require a reductive environment for the optimal activity of disulfide reductases and other thiol-dependent enzymes, how these reductive environments are established and maintained remain unknown. Our goal in this study was to begin to elucidate the redox control systems responsible for maintaining redox-sensitive enzymatic activities in the phagolysosome of murine macrophages. Through the use of specific inhibitors and genetic knockdown of known redox enzymes, we identified redox pathways that influence phagosomal disulfide reduction. In particular, known inhibitors of the NADPH-dependent selenoprotein, thioredoxin reductase, were shown to inhibit phagosomal disulfide reduction and phagosomal proteolysis. This was supported by the observation that conditional deletion of the selenocysteine tRNA in macrophages decreased phagosomal disulfide reduction capacity. In addition, pharmacologic inhibition of the pentose phosphate pathway decreased rates of disulfide reduction and proteolysis in the phagosome, implicating NADPH as a source of phagosomal reductive energy. Finally, by analyzing the effect of extracellular redox couples, such as cysteine:cystine on thiol-dependent phagosomal processes, we demonstrated that the extracellular space can additionally supply the phagosome with reductive energy. Collectively, these data demonstrate that defined cytosolic reductive pathways act in concert with the uptake of cysteine from the extracellular space to support thiol-dependent chemistries in the phagosome.

Prostate Cancer Immunotherapy: Exploiting the HLA Class II Pathway in Vaccine Design

Prostate cancer is the second most diagnosed cancer in men and current treatment of advanced prostate cancer is ineffective. Immunotherapy has emerged as a promising treatment option for metastatic prostate cancer but its clinical application is still in the early stages of development. In order to treat metastatic prostate tumors, new directions must be taken to improve current immunotherapeutic strategies. These include the identification of effective tumor antigens (Ags), the induction of the HLA class II pathway for Ag processing and CD4⁺ T cell activation, and the ability of tumor cells to act like Ag presenting cells. In this review, we suggest a model for tumor Ag selection, epitope modification and self-processing for presentation by class II proteins as a means of restoring immune activation and tumor clearance. We also outline the importance of a Gamma-IFN-inducible Lysosomal Thiol reductase (GILT) in Ag and modified peptide processing by tumor cells, generation of functional epitopes for T cell recognition, and inclusion of immune checkpoint blockers in cancer immunotherapy. Taken together, this review provides a framework for the future development of novel cancer vaccines and the improvement of existing immunotherapeutics in prostate cancer.

Diverse cellular and organismal functions of the lysosomal thiol reductase GILT

Gamma-interferon-inducible lysosomal thiol reductase (GILT) is the only enzyme known to catalyze disulfide bond reduction in the endocytic pathway. GILT facilitates the presentation of a subset of epitopes from disulfide bond-containing antigens. Enhanced presentation of MHC class II-restricted epitopes alters central tolerance and modulates CD4+ T cell-mediated autoimmunity. Improved cross-presentation of viral epitopes results in improved cross-priming of viral-specific CD8+ T cells. GILT regulates the cellular redox state. In GILT-/- cells, there is a shift from the reduced to the oxidized form of glutathione, resulting in mitochondrial autophagy, decreased superoxide dismutase 2, and elevated superoxide levels. GILT expression diminishes cellular activation, including decreased phosphorylated ERK1/2, and decreases cellular proliferation. GILT enhances the activity of bacterial hemolysins, such as listeriolysin O, and increases bacterial replication and infection. GILT expression in cancer cells is associated with improved patient survival. These diverse roles of GILT are discussed.

Conformational instability governed by disulfide bonds partitions the dominant from subdominant helper T-cell responses specific for HIV-1 envelope glycoprotein gp120

Most individuals infected with human immunodeficiency virus type 1 (HIV-1) generate a CD4(+) T-cell response that is dominated by a few epitopes. Immunodominance may be counterproductive because a broad CD4(+) T-cell response is associated with reduced viral load. Previous studies indicated that antigen three-dimensional structure controls antigen processing and presentation and therefore CD4(+) T-cell epitope dominance. Dominant epitopes occur adjacent to the V1-V2, V3, and V4 loops because proteolytic antigen processing in the loops promotes presentation of adjacent sequences. In this study, three gp120 (strain JR-FL) variants were constructed, in which deletions of single outer-domain disulfide bonds were expected to introduce local conformational flexibility and promote presentation of additional CD4(+) T-cell epitopes. Following mucosal immunization of C57BL/6 mice with wild-type or variant gp120 lacking the V3-flanking disulfide bond, the typical pattern of dominant epitopes was observed, suggesting that the disulfide bond posed no barrier to antigen presentation. In mice that lacked gamma interferon-inducible lysosomal thioreductase (GILT), proliferative responses to the typically dominant epitopes of gp120 were selectively depressed, and the dominance pattern was rearranged. Deletion of the V3-flanking disulfide bond or one of the V4-flanking disulfide bonds partially restored highly proliferative responses to the typically dominant epitopes. These results reveal an acute dependence of dominant CD4(+) T-cell responses on the native gp120 conformation.

Screening for candidate genes related to breast cancer with cDNA microarray analysis

Objective

The aim of this study was to reveal the exact changes during the occurrence of breast cancer to explore significant new and promising genes or factors related to this disease.

Methods

We compared the gene expression profiles of breast cancer tissues with its uninvolved normal breast tissues as controls using the cDNA microarray analysis in seven breast cancer patients. Further, one representative gene, named IFI30, was quantitatively analyzed by real-time PCR to confirm the result of the cDNA microarray analysis.

Results

A total of 427 genes were identified with significantly differential expression, 221 genes were up-regulated and 206 genes were down-regulated. And the result of cDNA microarray analysis was validated by detection of IFI30 mRNA level changes by real-time PCR. Genes for cell proliferation, cell cycle, cell division, mitosis, apoptosis, and immune response were enriched in the up-regulated genes, while genes for cell adhesion, proteolysis, and transport were significantly enriched in the down-regulated genes in breast cancer tissues compared with normal breast tissues by a gene ontology analysis.

Conclusion

Our present study revealed a range of differentially expressed genes between breast cancer tissues and normal breast tissues, and provide candidate genes for further study focusing on the pathogenesis and new biomarkers for breast cancer.

Identification of interferon-γ-inducible-lysosomal thiol reductase (GILT) gene in goldfish (Carassius auratus) and its immune response to LPS challenge

The interferon-γ-inducible lysosomal thiol reductase (GILT) has been demonstrated to play an important role in the processing and presentation of MHC class II restricted antigen (Ag) by catalyzing disulfide bond reduction. In this study, we cloned a GILT gene homolog from goldfish (designated gGILT), a kind of precious freshwater fish with high market value. The open reading frame of gGILT consists of 756 bases encoding a protein of 251 amino acids with an estimated molecular mass of 27.8 kDa and a theoretical isoelectric point of 5.24. The deduced protein possesses the typical structural features of known GILT proteins, including an active-site motif, a GILT signature sequence, and 10 conserved cysteines. RT-PCR results showed that gGILT and gIFN-γ (goldfish IFN-γ) mRNA were expressed in a tissue-specific manner and obviously up-regulated in splenocytes and the cells from head kidney after induction with LPS. Recombinant gGILT fused with His6 tag was efficiently expressed in Escherichia coli BL21 (DE3) and purified by Ni-NTA affinity chromatography. Further study revealed that gGILT was capable of catalyzing the reduction of the interchain disulfide bonds from intact IgG. This study shows that gGILT may be involved in the immune response to bacteria challenge and maintain first line of innate immune defense at basal level in goldfish. It also provides the basis for investigating on the role of GILT using goldfish as an animal model.

Elevation of c-MYC disrupts HLA class II-mediated immune recognition of human B cell tumors

Elevated levels of the transcription factor c-myc are strongly associated with various cancers, and in particular B cell lymphomas. Although many of c-MYC's functions have been elucidated, its effect on the presentation of Ag through the HLA class II pathway has not been reported previously. This is an issue of considerable importance, given the low immunogenicity of many c-MYC-positive tumors. We report in this paper that increased c-MYC expression has a negative effect on the ability of B cell lymphomas to functionally present Ags/peptides to CD4(+) T cells. This defect was associated with alterations in the expression of distinct cofactors as well as interactions of antigenic peptides with class II molecules required for the presentation of class II-peptide complexes and T cell engagement. Using early passage Burkitt's lymphoma (BL) tumors and transformed cells, we show that compared with B lymphoblasts, BL cells express decreased levels of the class II editor HLA-DM, lysosomal thiol-reductase GILT, and a 47-kDa enolase-like protein. Functional Ag presentation was partially restored in BL cells treated with a c-MYC inhibitor, demonstrating the impact of this oncogene on Ag recognition. This restoration of HLA class II-mediated Ag presentation in early passage BL tumors/cells was linked to enhanced HLA-DM expression and a concurrent decrease in HLA-DO in BL cells. Taken together, these results reveal c-MYC exerts suppressive effects at several critical checkpoints in Ag presentation, which contribute to the immunoevasive properties of BL tumors.

Macronutrient deprivation modulates antigen trafficking and immune recognition through HSC70 accessibility

B lymphocytes exploit macroautophagy to capture cytoplasmic and nuclear proteins within autophagosomes. Fusion of autophagosomes with lysosomes and endosomes facilitates content proteolysis, with the resulting peptides selectively binding MHC class II (MHC II) molecules, which are displayed for recognition by T lymphocytes. Nutrient deprivation or stress amplified this pathway, favoring increased MHC II presentation of cytoplasmic Ags targeted to autophagosomes. By contrast, this stress diminished MHC II presentation of membrane Ags including the BCR and cytoplasmic proteins that use the chaperone-mediated autophagy pathway. Whereas intracellular protease activity increased with nutrient stress, endocytic trafficking and proteolytic turnover of the BCR was impaired. Addition of macronutrients such as high molecular mass proteins restored endocytosis and Ag presentation, evidence of tightly regulated membrane trafficking dependent on macronutrient status. Altering cellular levels of the cytosolic chaperone HSC70 was sufficient to overcome the inhibitory effects of nutritional stress on BCR trafficking and Ag presentation. Together, these results reveal a key role for macronutrient sensing in regulating immune recognition and the importance of HSC70 in modulating membrane trafficking pathways during cellular stress.

IL12Rβ1: the cytokine receptor that we used to know

Human IL12RB1 encodes IL12Rβ1, a type I transmembrane receptor that is an essential component of the IL12- and IL23-signaling complex. IL12RB1 is well-established as being a promoter of delayed type hypersensitivity (DTH), the immunological reaction that limits tuberculosis. However, recent data demonstrate that in addition to promoting DTH, IL12RB1 also promotes autoimmunity. The contradictory roles of IL12RB1 in human health raises the question, what are the factors governing IL12RB1 function in a given individual, and how is inter-individual variability in IL12RB1 function introduced? Here we review recent data that demonstrate individual variability in IL12RB1 function is introduced at the epigenetic, genomic polymorphism, and mRNA splicing levels. Where and how these differences contribute to disease susceptibility and outcome are also reviewed. Collectively, recent data support a model wherein IL12RB1 sequence variability - whether introduced at the genomic or post-transcriptional level - contributes to disease, and that human IL12RB1 is not as simple a gene as we once believed.

Transcriptional profiling and co-expression network analysis identifies potential biomarkers to differentiate chronic hepatitis B and the caused cirrhosis

Liver cirrhosis is one of the most common non-neoplastic causes of mortality worldwide. Chronic hepatitis B (CHB) is a major cause of liver cirrhosis in China. To find biomarkers for the diagnosis of CHB caused cirrhosis (HBC), we examined the transcriptional profiling of CHB and HBC. The leukocyte samples of CHB (n = 5) and HBC (n = 5) were analyzed by microarray. The results showed that 2128 mapped genes were differentially expressed between CHB and HBC (fold change ≥ 2.0, p < 0.05). Gene ontology (GO) analysis indicated that these 2128 differentially expressed genes (DEGs) were enriched for immune response and cell formation functions mostly. Moreover, co-expression networks using the k-core algorithm were established to determine the core genes, which may play important roles in the progression of CHB to HBC. There were markedly different gene co-expression patterns in CHB and HBC. We validated the five core genes, CASP1, TGFBI, IFI30, HLA-DMA and PAG1 in CHB (n = 60) and HBC (n = 60) by quantitative RT-PCR. The expression of the five genes were consistent with microarray, and there were statistically significant co-expression patterns of TGFβ1, PAG1 and HLA-DMA mRNA (Pearson correlation coefficient >0.6). Furthermore, we constructed an mRNA panel of TGFBI, IFI30, HLA-DMA and PAG1 (TIPH HBCtest) by means of a logistic regression model, and evaluated the TIPH HBCtest for HBC diagnosis by area under the receiver operating characteristic curve (AUC) analysis, which showed a higher accuracy (AUC = 0.903). This study suggested that there are particular transcriptional profiles, gene co-expression patterns and core genes in CHB and HBC. The TIPH HBC test may be useful in the diagnosis of HBC from CHB.

Absence of gamma-interferon-inducible lysosomal thiol reductase (GILT) is associated with poor disease-free survival in breast cancer patients

Tumor immunosurveillance is known to be of critical importance in controlling tumorigenesis and progression in various cancers. The role of gamma-interferon-inducible lysosomal thiol reductase (GILT) in tumor immunosurveillance has recently been studied in several malignant diseases, but its role in breast cancer remains to be elucidated. In the present study, we found GILT as a significant different expressed gene by cDNA microarray analysis. To further determine the role of GILT in breast cancer, we examined GILT expression in breast cancers as well as noncancerous breast tissues by immunohistochemistry and real-time PCR, and assessed its association with clinicopathologic characteristics and patient outcome. The absence of GILT expression increased significantly from 2.02% (2/99) in noncancerous breast tissues to 15.6% (34/218) in breast cancer tissues (P<0.001). In accordance with its proliferation inhibiting function, GILT expression was inversely correlated with Ki67 index (P<0.05). In addition, absence of GILT was positively correlated with adverse characteristics of breast cancers, such as histological type, tumor size, lymph nodes status, and pTNM stage (P<0.05). Consistently, breast cancers with reduced GILT expression had poorer disease-free survival (P<0.005). Moreover, significantly decreased expression of GILT was found in both primary and metastatic breast cancer cells, in contrast to normal epithelial cells. These findings indicate that GILT may act as a tumor suppressor in breast cancer, in line with its previously suggested role in anti-tumor immunity. Thus, GILT has the potential to be a novel independent prognostic factor in breast cancer and further studies are needed to illustrate the underlying mechanism of this relationship.

Disruption of HLA class II antigen presentation in Burkitt lymphoma: implication of a 47,000 MW acid labile protein in CD4+ T-cell recognition

While Burkitt lymphoma (BL) has a well-known defect in HLA class I-mediated antigen presentation, the exact role of BL-associated HLA class II in generating a poor CD4(+) T-cell response remains unresolved. Here, we found that BL cells are deficient in their ability to optimally stimulate CD4(+) T cells via the HLA class II pathway. This defect in CD4(+) T-cell recognition was not associated with low levels of co-stimulatory molecules on BL cells, as addition of external co-stimulation failed to elicit CD4(+) T-cell activation by BL. Further, the defect was not caused by faulty antigen/class II interaction, because antigenic peptides bound with measurable affinity to BL-associated class II molecules. Interestingly, functional class II-peptide complexes were formed at acidic pH 5·5, which restored immune recognition. Acidic buffer (pH 5·5) eluate from BL cells contained molecules that impaired class II-mediated antigen presentation and CD4(+) T-cell recognition. Biochemical analysis showed that these molecules were greater than 30,000 molecular weight in size, and proteinaceous in nature. In addition, BL was found to have decreased expression of a 47,000 molecular weight enolase-like molecule that enhances class II-mediated antigen presentation in B cells, macrophages and dendritic cells, but not in BL cells. These findings demonstrate that BL likely has multiple defects in HLA class II-mediated antigen presentation and immune recognition, which may be exploited for future immunotherapies.

γ-Interferon-inducible lysosomal thiol reductase (GILT) maintains phagosomal proteolysis in alternatively activated macrophages

Although it is known that lysosomal cysteine cathepsins require a reducing environment for optimal activity, it is not firmly established how these enzymes are maintained in their reduced-active state in the acidic and occasionally oxidative environment within phagosomes and lysosomes. γ-Interferon-inducible lysosomal thiol reductase (GILT) has been the only enzyme described in the endosomes, lysosomes, and phagosomes with the potential to catalyze the reduction of cysteine cathepsins. Our goal in the current study was to assess the effect of GILT on major phagosomal functions with an emphasis on proteolytic efficiency in murine bone marrow-derived macrophages. Assessment of phagosomal disulfide reduction upon internalization of IgG-opsonized experimental particles confirmed a major role for GILT in phagosomal disulfide reduction in both resting and interferon-γ-activated macrophages. Furthermore we observed a decrease in early phagosomal proteolytic efficiency in GILT-deficient macrophages, specifically in the absence of an NADPH oxidase-mediated respiratory burst. This deficiency was more prominent in IL-4-activated macrophages that inherently possess lower levels of NADPH oxidase activity. Finally, we provide evidence that GILT is required for optimal activity of the lysosomal cysteine protease, cathepsin S. In summary, our results suggest a role for GILT in maintaining cysteine cathepsin proteolytic efficiency in phagosomes, particularly in the absence of high NADPH oxidase activity, which is characteristic of alternatively activated macrophages.

Identification of gamma-interferon-inducible lysosomal thiol reductase (GILT) homologues in the fruit fly Drosophila melanogaster

Gamma-interferon-inducible lysosomal thiol reductase (GILT) has been demonstrated to be involved in the immune response to bacterial challenge in various organisms. However, little is known about GILT function in innate immunity. Drosophila has been commonly used as a model for the study of the innate immune response of invertebrates. Here, we identify the CG9796, CG10157, and CG13822 genes of fruit fly Drosophila melanogaster as GILT homologues. All deduced Drosophila GILT coding sequences contained the major characteristic features of the GILT protein family: the GILT signature CQHGX2ECX2NX4C sequence and the active site CXXC or CXXS motif. The mRNA transcript levels of the Drosophila GILT genes were up-regulated after Gram-negative bacteria Escherichia coli DH5α infection. Moreover, a bacterial load assay showed that over-expression of Drosophila GILT in fat body or hemocytes led to a low bacterial colony number whereas knock-down of Drosophila GILT in fat body or hemocytes led to a high bacterial colony number when compared to a wild-type control. These results indicate that the Drosophila GILTs are very likely to play a role in the innate immune response upon bacterial challenge of Drosophila host defense. This study may provide the basis for further study on GILT function in innate immunity.