IRGB10 Liberates Bacterial Ligands for Sensing by the AIM2 and Caspase-11-NLRP3 Inflammasomes.

The inflammasome is an intracellular signaling complex, which on recognition of pathogens and physiological aberration, drives activation of caspase-1, pyroptosis, and the release of the pro-inflammatory cytokines IL-1ß and IL-18. Bacterial ligands must secure entry into the cytoplasm to activate inflammasomes; however, the mechanisms by which concealed ligands are liberated in the cytoplasm have remained unclear. Here, we showed that the interferon-inducible protein IRGB10 is essential for activation of the DNA-sensing AIM2 inflammasome by Francisella novicida and contributed to the activation of the LPS-sensing caspase-11 and NLRP3 inflammasome by Gram-negative bacteria. IRGB10 directly targeted cytoplasmic bacteria through a mechanism requiring guanylate-binding proteins. Localization of IRGB10 to the bacterial cell membrane compromised bacterial structural integrity and mediated cytosolic release of ligands for recognition by inflammasome sensors. Overall, our results reveal IRGB10 as part of a conserved signaling hub at the interface between cell-autonomous immunity and innate immune sensing pathways.

GBP2 is a prognostic biomarker and associated with immunotherapeutic responses in gastric cancer.

BACKGROUND: The interferon-induced protein known as guanylate-binding protein 2 (GBP2) has been linked to multiple different cancer types as an oncogenic gene. Although the role of GBP2 in cancer has been preliminarily explored, it is unclear how this protein interacts with tumor immunity in gastric cancer. METHODS: The expression, prognostic value, immune-correlations of GBP2 in gastric cancer was explored in multiple public and in-house cohorts. In addition, the pan-cancer analysis was performed to investigate the immunological role of GBP2 based on The Cancer Genome Atlas (TCGA) dataset, and the predictive value of GBP2 for immunotherapy was also examined in multiple public cohorts. RESULTS: GBP2 was highly expressed in tumor tissues and associated with poor prognosis in gastric cancer. In addition, GBP2 was associated with the immune-hot phenotype. To be more specific, GBP2 was positively related to immuno-modulators, tumor-infiltrating immune cells (TIICs), immunotherapy biomarkers, and even well immunotherapeutic response. In addition to gastric cancer, GBP2 was expected to be an indicator of high immunogenicity in most cancer types. Importantly, GBP2 could predict the immunotherapeutic responses in at least four different cancer types, including melanoma, urothelial carcinoma, non-small cell lung cancer, and breast cancer. CONCLUSIONS: To sum up, GBP2 expression is a promising pan-cancer biomarker for estimating the immunological characteristics of tumors and may be utilized to detect immuno-hot tumors in gastric cancer.

GBP2 serves as a novel prognostic biomarker and potential immune microenvironment indicator in renal cell carcinoma.

Since the application of immune checkpoint therapy (ICT) has gradually become a new strategy for clear cell renal cell carcinoma (ccRCC) treatment, biomarkers that predict the individual response to ICT is needed. This study aimed to identify a new clinical indicator for postoperative surveillance of ccRCC and prediction of ICT response. We investigated the GBP2 expression and its relation with immune cell infiltration in tumor microenvironment using public databases, clinical specimens and ccRCC cell lines. Bioinformatic analysis using public database revealed that GBP2 expression is higher in cancer tissues than in adherent normal tissues among different cancer types including ccRCC, and the same results were acquired from clinical tissue samples tested by Western Blot and PCR. In ccRCC cell lines, CCk-8 proliferation assay and apoptosis assessment suggested GBP2 facilitates the malignancy of ccRCC. 286 ccRCC patients were randomly divided into a training or validation cohort, and immunohistochemistry (IHC) and Kaplan-Meier analysis revealed that higher GBP2 expression is related to worse prognosis. C-index analysis implied that integrating GBP2 expression with TNM stage improved the accuracy in predicting prognosis of ccRCC patients compared to the solitary use of either. Bioinformatic analysis implied a relation between GBP2 and immunity, and GBP2 expression is positively related with suppressive immune markers in ccRCC microenvironment. Taken together, our study demonstrated the potential of GBP2 to sever as a prognostic predictor of ccRCC, and an association between GBP2 and tumor-infiltrating lymphocytes in ccRCC was observed, making it a promising indicator of ICT response.

Guanylate-binding protein 2 orchestrates innate immune responses against murine norovirus and is antagonized by the viral protein NS7.

Noroviruses are the main causative agents of acute viral gastroenteritis, but the host factors that restrict their replication remain poorly identified. Guanylate-binding proteins (GBPs) are interferon (IFN)-inducible GTPases that exert broad antiviral activity and are important mediators of host defenses against viral infections. Here, we show that both IFN-γ stimulation and murine norovirus (MNV) infection induce GBP2 expression in murine macrophages. Results from loss- and gain-of-function assays indicated that GBP2 is important for IFN-γ-dependent anti-MNV activity in murine macrophages. Ectopic expression of MNV receptor (CD300lf) in human HEK293T epithelial cells conferred susceptibility to MNV infection. Importantly, GBP2 potently inhibited MNV in these human epithelial cells. Results from mechanistic dissection experiments revealed that the N-terminal G domain of GBP2 mediates these anti-MNV effects. R48A and K51A substitutions in GBP2, associated with loss of GBP2 GTPase activity, attenuated the anti-MNV effects of GBP2. Finally, we found that nonstructural protein 7 (NS7) of MNV co-localizes with GBP2 and antagonizes the anti-MNV activity of GBP2. These findings reveal that GBP2 is an important mediator of host defenses against murine norovirus.

RGG-motif containing mRNA export factor Gbp2 acts as a translation repressor.

Complex cascades of RNA-binding proteins regulate the mRNA metabolism and influence gene expression. Several distinct proteins act at different stages of mRNA life cycle. SR family proteins in yeast are implicated in mRNA processing and nuclear export. In this report, we uncover the role of an SR/RGG-motif containing mRNA export factor Gbp2 in mRNA translation regulation. We demonstrate that Gbp2 localizes to cytoplasmic granules upon heat shock and oxidative stress. Our pull-down assays demonstrate that Gbp2 directly binds to the conserved translation factor eIF4G1 via its RGG motif. We further mapped the region on eIF4G1 to which Gbp2 binds and observed that the binding region overlaps with another translation repressor Sbp1. We found that the RGG-motif deletion mutant is defective in localizing to polysome fractions. Upon tethering Gbp2 to a GFP reporter mRNA in vivo, translation of GFP reporter decreased significantly indicating that Gbp2 acts as a translation repressor. Consistent with these results, we show that Gbp2 can directly repress mRNA translation in the in vitro translation systems in an RGG-motif dependent manner. Taken together, our results establish that the mRNA export factor Gbp2 has a vital role in repressing translation of mRNA. We propose that Gbp2 is a multifaceted RGG-motif protein responsible for translational repression without affecting mRNA levels.

Nuclear mRNA Quality Control and Cytoplasmic NMD Are Linked by the Guard Proteins Gbp2 and Hrb1.

Pre-mRNA splicing is critical for cells, as defects in this process can lead to altered open reading frames and defective proteins, potentially causing neurodegenerative diseases and cancer. Introns are removed in the nucleus and splicing is documented by the addition of exon-junction-complexes (EJCs) at exon-exon boundaries. This "memory" of splicing events is important for the ribosome, which translates the RNAs in the cytoplasm. In case a stop codon was detected before an EJC, translation is blocked and the RNA is eliminated by the nonsense-mediated decay (NMD). In the model organism Saccharomyces cerevisiae, two guard proteins, Gbp2 and Hrb1, have been identified as nuclear quality control factors for splicing. In their absence, intron-containing mRNAs leak into the cytoplasm. Their presence retains transcripts until the process is completed and they release the mRNAs by recruitment of the export factor Mex67. On transcripts that experience splicing problems, these guard proteins recruit the nuclear RNA degradation machinery. Interestingly, they continue their quality control function on exported transcripts. They support NMD by inhibiting translation and recruiting the cytoplasmic degradation factors. In this way, they link the nuclear and cytoplasmic quality control systems. These discoveries are also intriguing for humans, as homologues of these guard proteins are present also in multicellular organisms. Here, we provide an overview of the quality control mechanisms of pre-mRNA splicing, and present Gbp2 and Hrb1, as well as their human counterparts, as important players in these pathways.

Guanylate-binding protein-2 inhibits colorectal cancer cell growth and increases the sensitivity to paclitaxel of paclitaxel-resistant colorectal cancer cells by interfering Wnt signaling.

Among the GTPase family members, guanylate-binding protein-1 (GBP-1) is the most thoroughly studied member in a plethora of human cancers. GBP-2, on the other hand, remains limitedly studied. We wonder how GBP-2 participates in colorectal carcinoma (CRC) as well as the paclitaxel (PTX)-resistance of CRC. In this study, the authors are determined to dig into the role that GBP-2 plays in the sensitivity of CRC to PTX, therefore, possibly indicating a promising gene therapy target for CRC. Forced expression of GBP-2 gene was done by plasmid transfection. Reverse transcriptase-polymerase chain reaction and immunoblot were conducted to detect the expression of GBP-2 messenger RNA (mRNA) and protein, respectively. Colony foci formation assay, transwell invasion assay, and flow cytofluorometry were done to determine the proliferation, invasion, and apoptosis of PTX-resistant and PTX-sensitive CRC cell lines, respectively. The level of GBP-2 mRNA and protein in PTX-resistant CRC cell lines was significantly lower than in nonresistant cell lines. Forced exogenous expression of GBP-2 in PTX-resistant CRC cell lines resulted in more sensitivity to PTX because of the demonstration of less cell proliferation, invasion, and more apoptosis. Wnt signaling was suppressed when GBP-2 was upregulated by transfection of GBP-2 overexpression plasmids, and Wnt signaling did not affect GBP-2 expression. GBP-2 upregulation could enhance the killing effect of PTX in both PTX-sensitive CRC cells and PTX-resistant CRC cells by suppressing Wnt signaling.

Up-regulation of GBP2 is Associated with Neuronal Apoptosis in Rat Brain Cortex Following Traumatic Brain Injury.

Guanylate binding protein 2 (GBP2) is one member of GBP family. Recently, GBP2 has been proposed to be a novel target of anti-cancer drugs. However, the role of GBP2 in the traumatic brain injury (TBI) is very limited. In this study, we sought to define GBP2's role in brain injury. GBP2 protein levels were significantly increased in the brain 3 days after injury, suggesting a functional role for GBP2 in TBI. Neuronal cells overexpressing GBP2 exhibited up-regulation of co-location of GBP2 and NeuN following TBI, suggesting that GBP2 potentiates the neuron apoptosis. To confirm the role of GBP2 in neuron apoptosis process, we employed a highly potent inhibitor of GBP2 (GBP2 RNAi). In H2O2-stimulated PC12 cells, in vitro blockade of GBP2 activity using GBP2 RNAi markedly attenuated the neuron apoptosis number. GBP2 RNAi also inhibited the expression levels of active caspase3 and p-Stat1. Furthermore, we found the expression of p-Stat1 in line with GBP2 and GBP2 interacted with p-Stat1 following TBI. The Jak2 inhibitor, AG490 inhibited this interaction and decreased the active caspase3 expression as well as promoted the functional recovery. Taken together, these data suggest that GBP2 RNAi has a protective effect in a rat TBI. This study demonstrates that GBP2 is an important positive regulator of TBI and is a promising therapeutic target for brain injury.

The genes Scgb1a1, Lpo and Gbp2 characteristically expressed in peri-implant epithelium of rats.

OBJECTIVES: The peri-implant epithelium (PIE) plays an important role in the prevention against initial stage of inflammation. To minimize the risk of peri-implantitis, it is necessary to understand the biological characteristics of the PIE. The aim of this study was to investigate the characteristic gene expression profile of PIE as compared to junctional epithelium (JE) using laser microdissection and microarray analysis. METHODS: Left upper first molars of 4-week-old rat were extracted, and titanium alloy implants were placed. Four weeks after surgery, samples were harvested by laser microdissection, and total RNA samples were isolated. Comprehensive analyses of genes expressed in the JE and PIE were performed using microarray analysis. Confirmation of the differential expression of selected genes was performed by quantitative real-time polymerase chain reaction and immunohistochemistry. RESULTS: The microarray analysis showed that 712 genes were more than twofold change upregulated in the PIE compared with the JE. Genes Scgb1a1 were significantly upregulated more than 19.1-fold, Lpo more than 19.0-fold, and Gbp2 more than 8.9-fold, in the PIE (P < 0.01). Immunohistochemical localization of SCGB1A1, LPO, and GBP2 was observed in PIE. CONCLUSION: The present results suggested that genes Scgb1a1, Lpo, and Gbp2 are characteristically expressed in the PIE.

CENPA facilitates glioma stem cell stemness and suppress ferroptosis to accelerate glioblastoma multiforme progression by promoting GBP2 transcription.

The function of glioma stem cells (GSCs) is closely related to the progression of glioblastoma multiforme (GBM). Centromere protein A (CENPA) has been confirmed to be related to the poor prognosis of GBM patients. However, whether CENPA regulates GSCs function to mediate GBM progression is still unclear. GSCs were isolated from GBM cells. The expression of CENPA and guanylate-binding protein 2 (GBP2) was examined by quantitative real-time PCR and western blot. GSCs proliferation and stemness were assessed using EdU assay and sphere formation assay. Cell ferroptosis was evaluated by detecting related factors. The interaction between CENPA and GBP2 was analyzed by ChIP assay and dual-luciferase reporter assay. Animal experiments were conducted to measure the effect of CENPA knockdown on the tumorigenicity of GSCs in vivo. CENPA was upregulated in GBM tissues and GSCs. CENPA knockdown inhibited GSCs proliferation, stemnness, and promoted ferroptosis. GBP2 was overexpressed in GBM tissues and GSCs, and CENPA enhanced GBP2 transcription by binding to its promoter region. CENPA overexpression accelerated GSCs proliferation and stemnness and suppressed ferroptosis, while GBP2 knockdown reversed these effects. Downregulation of CENPA reduced the tumorigenicity of GSCs by decreasing GBP2 expression in vivo. In conclusion, CENPA enhanced GBP2 transcription to increase its expression, thus accelerating GSCs proliferation and stemnness and repressing ferroptosis. Our findings promote a new idea for GBM treatment.

Exploring the immune microenvironment of osteosarcoma through T cell exhaustion-associated gene expression: a study on prognosis prediction.

Background: Osteosarcoma is a highly aggressive type of bone cancer with a poor prognosis. In the tumor immune microenvironment, T-cell exhaustion can occur due to various factors, leading to reduced tumor-killing ability. The purpose of this study was to construct a prognostic model based on T-cell exhaustion-associated genes in osteosarcoma. Methods: Patient data for osteosarcoma were retrieved from the TARGET and GEO databases. Consensus clustering was employed to identify two novel molecular subgroups. The dissimilarities in the tumor immune microenvironment between these subgroups were evaluated using the "xCell" algorithm. GO and KEGG analyses were conducted to elucidate the underlying mechanisms of gene expression. Predictive risk models were constructed using the least absolute shrinkage and selection operator algorithm and Cox regression analysis. To validate the prognostic significance of the risk gene expression model at the protein level, immunohistochemistry assays were performed on osteosarcoma patient samples. Subsequently, functional analysis of the key risk gene was carried out through in vitro experimentation. Results: Four gene expression signatures (PLEKHO2, GBP2, MPP1, and VSIG4) linked to osteosarcoma prognosis were identified within the TARGET-osteosarcoma cohort, categorizing patients into two subgroups. The resulting prognostic model showed strong predictive capability, with area under the receiver operating characteristic curve (AUC) values of 0.728/0.740, 0.781/0.658, and 0.788/0.642 for 1, 3, and 5-year survival in both training and validation datasets. Notably, patients in the low-risk group had significantly higher stromal, immune, and ESTIMATE scores compared to high-risk counterparts. Additionally, a nomogram was developed, exhibiting high accuracy in predicting the survival outcome of osteosarcoma patients. Immunohistochemistry, Kaplan-Meier, and time-dependent AUC analyses consistently supported the prognostic value of the risk model within our osteosarcoma patient cohort. In vitro experiments provided additional validation by demonstrating that the downregulation of GBP2 promoted the proliferation, migration, and invasion of osteosarcoma cells while inhibiting apoptosis. Conclusion: The current study established a prognostic signature associated with TEX-related genes and elucidated the impact of the pivotal gene GBP2 on osteosarcoma cells via in vitro experiments. Consequently, it introduces a fresh outlook for clinical prognosis prediction and sets the groundwork for targeted therapy investigations in osteosarcoma.

GBP2 promotes M1 macrophage polarization by activating the notch1 signaling pathway in diabetic nephropathy.

Background: Diabetic nephropathy (DN) is one of the most common diabetic complications, which has become the primary cause of end-stage renal disease (ESRD) globally. Macrophage infiltration has been proven vital in the occurrence and development of DN. This study was designed to investigate the hub genes involved in macrophage-mediated inflammation of DN via bioinformatics analysis and experimental validation. Methods: Gene microarray datasets were obtained from the Gene Expression Omnibus (GEO) public website. Integrating the CIBERSORT, weighted gene co-expression network analysis (WGCNA) and DEGs, we screened macrophage M1-associated key genes with the highest intramodular connectivity. Subsequently, the Least Absolute Shrinkage and Selection Operator (LASSO) regression was utilized to further mine hub genes. GSE104954 acted as an external validation to predict the expression levels and diagnostic performance of these hub genes. The Nephroseq online platform was employed to evaluate the clinical implications of these hub genes. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed to elucidate the dominant biological functions and signal pathways. Finally, we conducted experiments to verify the role of GBP2 in M1 macrophage-mediated inflammatory response and the underlying mechanism of this role. Results: Sixteen DEGs with the highest connectivity in M1 macrophages-associated module (paleturquoise module) were determined. Subsequently, we identified four hub genes through LASSO regression analysis, including CASP1, MS4A4A, CD53, and GBP2. Consistent with the training set, expression levels of these four hub genes manifested memorably elevated and the ROC curves indicated a good diagnostic accuracy with an area under the curve of greater than 0.8. Clinically, enhanced expression of these four hub genes predicted worse outcomes of DN patients. Given the known correlation between the first three hub genes and macrophage-mediated inflammation, experiments were performed to demonstrate the effect of GBP2, which proved that GBP2 contributed to M1 polarization of macrophages by activating the notch1 signaling pathway. Conclusion: Our findings detected four hub genes, namely CASP1, MS4A4A, CD53, and GBP2, may involve in the progression of DN via pro-inflammatory M1 macrophage phenotype. GBP2 could be a promising prognostic biomarker and intervention target for DN by regulating M1 polarization.

GBP2 upregulated in LPS-stimulated macrophages-derived exosomes accelerates septic lung injury by activating epithelial cell NLRP3 signaling.

Macrophages infiltration is a crucial factor causing Sepsis-associated acute lung injury (ALI). Accumulating evidence suggests macrophages-alveolar epithelial cells communication is proven to be critical in ALI. However, little is known regarding how activated macrophages regulated sepsis-associated ALI. To explore the role of macrophages-alveolar epithelial cells communication in the ALI process, our data revealed that Lipopolysaccharides-induced macrophages-derived exosomes (L-Exo) induced sepsis-associated ALI and caused alveolar epithelial cells damage. Moreover, Guanylate-binding protein 2 (GBP2) was significantly upregulated in L-Exo, and NLRP3 inflammasomes was the direct target of GBP2. Further experimentation showed that GBP2 inhibition in vitro and in vivo reserves L-Exo effects, while GBP2 overexpression in vitro and in vivo promotes L-Exo effects. These results demonstrated that L-Exo contains excessive GBP2 and promotes inflammation through targeting NLRP3 inflammasomes, which induced alveolar epithelial cells dysfunction and pyroptosis. These findings demonstrate that L-Exo exerted a deleterious effect on ALI by regulating the GBP2/NLRP3 axis, which might provide new insight on ALI prevention and treatment.

A five-protein prognostic signature with GBP2 functioning in immune cell infiltration of clear cell renal cell carcinoma.

Clear cell renal cell carcinoma (ccRCC) is of poor clinical outcomes, and currently lacks reliable prognostic biomarkers. By analyzing the datasets of the Cancer Genome Atlas (TCGA) and the Clinical Proteomic Tumor Analysis Consortium (CPTAC), we established a five-protein prognostic signature containing GBP2, HLA-DRA, ISG15, ISG20 and ITGAX. Our data indicate that this signature was closely correlated with advanced stage, higher pathological grade, and unfavorable survivals in patients with ccRCC. We further functionally characterized GBP2. Overexpression of GBP2 enhanced the phosphorylation of STAT2 and STAT3 to trigger JAK-STAT signaling and promote cell migration and invasion in ccRCC. Treatment of Ruxolitinib, a specific inhibitor of JAK/STAT, attenuated the GBP2-mediated phenotypes. Patients with high GBP2 expression were accompanied with more infiltration of immune cells positively stained with CD3, CD8, CD68, and immune checkpoint markers PD-1 and CTLA4, which was validated by Opal multiplex immunohistochemistry in ccRCC tissues. More CD8 + T cells and CD68 + macrophages were observed in patients expressing high GBP2. Taken together, a five-protein prognostic signature was constructed in our study. GBP2 has an oncogenic role via modulating JAK-STAT signaling and tumor immune infiltration, and thus may serve as a potential therapeutic target in ccRCC.

Crystal structures reveal nucleotide-induced conformational changes in G motifs and distal regions in guanylate-binding protein 2.

Guanylate-binding proteins (GBPs) are interferon-inducible GTPases that confer protective immunity against a variety of intracellular pathogens including bacteria, viruses, and protozoan parasites. GBP2 is one of the two highly inducible GBPs, yet the precise mechanisms underlying the activation and regulation of GBP2, in particular the nucleotide-induced conformational changes in GBP2, remain poorly understood. In this study, we elucidate the structural dynamics of GBP2 upon nucleotide binding through crystallographic analysis. GBP2 dimerizes upon GTP hydrolysis and returns to monomer state once GTP is hydrolyzed to GDP. By determining the crystal structures of GBP2 G domain (GBP2GD) in complex with GDP and nucleotide-free full-length GBP2, we unveil distinct conformational states adopted by the nucleotide-binding pocket and distal regions of the protein. Our findings demonstrate that the binding of GDP induces a distinct closed conformation both in the G motifs and the distal regions in the G domain. The conformational changes in the G domain are further transmitted to the C-terminal helical domain, leading to large-scale conformational rearrangements. Through comparative analysis, we identify subtle but critical differences in the nucleotide-bound states of GBP2, providing insights into the molecular basis of its dimer-monomer transition and enzymatic activity. Overall, our study expands the understanding of the nucleotide-induced conformational changes in GBP2, shedding light on the structural dynamics governing its functional versatility. These findings pave the way for future investigations aimed at elucidating the precise molecular mechanisms underlying GBP2's role in the immune response and may facilitate the development of targeted therapeutic strategies against intracellular pathogens.

GBP2 as a potential prognostic predictor with immune-related characteristics in glioma.

Guanylate binding protein 2 (GBP2) is a member of the guanine binding protein family, and its relationship with prognostic outcomes and tumor immune microenvironments in glioma remains elusive. We found GBP2 were increased in glioma tissues at both mRNA and protein levels. Kaplan-Meier curves revealed that high GBP2 expression was linked with worse survival of glioma patients, and multivariate Cox regression analysis indicated that high GBP2 expression was an independent prognostic factor for glioma. Combined analysis in immune database revealed that the expression of GBP2 was significantly related to the level of immune infiltration and immunomodulators. Single-cell analysis illustrated the high expression of GBP2 in malignant glioma cells showed the high antigen presentation capability, which were confirmed by real-time polymerase chain reaction (qRT-PCR) data. Additionally, the hsa-mir-26b-5p and hsa-mir-335-5p were predicted as GBP2 regulators and were validated in U87 and U251 cells. Our results first decipher immune-related characteristics and noncoding regulators of GBP2 in glioma, which may provide insights into associated immunotherapies and prognostic predictor.

Plasmodium falciparum GBP2 Is a Telomere-Associated Protein That Binds to G-Quadruplex DNA and RNA.

In the early-diverging protozoan parasite Plasmodium, few telomere-binding proteins have been identified and several are unique. Plasmodium telomeres, like those of most eukaryotes, contain guanine-rich repeats that can form G-quadruplex structures. In model systems, quadruplex-binding drugs can disrupt telomere maintenance and some quadruplex-binding drugs are potent anti-plasmodial agents. Therefore, telomere-interacting and quadruplex-interacting proteins may offer new targets for anti-malarial therapy. Here, we report that P. falciparum GBP2 is such a protein. It was identified via 'Proteomics of Isolated Chromatin fragments', applied here for the first time in Plasmodium. In vitro, PfGBP2 binds specifically to G-rich telomere repeats in quadruplex form and it can also bind to G-rich RNA. In vivo, PfGBP2 partially colocalises with the known telomeric protein HP1 but is also found in the cytoplasm, probably due to its affinity for RNA. Consistently, its interactome includes numerous RNA-associated proteins. PfGBP2 is evidently a multifunctional DNA/RNA-binding factor in Plasmodium.

Adipogenic Transdifferentiation and Regulatory Factors Promote the Progression and the Immunotherapy Response of Renal Cell Carcinoma: Insights From Integrative Analysis.

Background: Adipogenic transdifferentiation was an important carcinogenic factor in various tumors, while studies on its role in clear cell renal cell carcinoma (ccRCC) were still relatively few. This study aimed to investigate its prognostic value and mechanism of action in ccRCC. Methods: Gene expression profiles and clinical data of ccRCC patients were obtained from The Cancer Genome Atlas database. Nonnegative matrix factorization was used for clustering. Gene set variation analysis (GSVA) and gene set enrichment analysis (GSEA) were used to analyze the pathways and biological process activities. single-sample GSEA (ssGSEA) was utilized to quantify the relative abundance of each immune cell. Tumor Immune Estimation Resource (TIMER) was used to evaluate the proportion of various immune infiltrating cells across diverse cancer types. Real-Time PCR was performed to examine the gene expression. R software was utilized to analyze the expression and prognostic role of genes in ccRCC. Results: A total of 49 adipose-related genes (ARGs) were screened for differential expression between normal and ccRCC tissues. Based on differentially expressed ARGs, patients with ccRCC were divided into two adipose subtypes with different clinical, molecular, and pathway characteristics. Patients in cluster A exhibited more advanced pathological stages, higher expressions of RARRES2 and immune checkpoint genes, higher immune infiltration scores, and less nutrient metabolism pathways. Adipose differentiation index (ADI) was constructed according to the above ARGs and survival data, and its robustness and accuracy was validated in different cohorts. In addition, it was found that the expression of ARGs was associated with immune cell infiltration and immune checkpoint in ccRCC, among which GBP2 was thought to be the most relevant gene to the tumor immune microenvironment and play a potential role in carcinogenesis and invasion of tumor cells. Conclusion: Our analysis revealed the consistency of higher adipogenic transdifferentiation of tumor cells with worse clinical outcomes in ccRCC. The 16-mRNA signature could predict the prognosis of ccRCC patients with high accuracy. ARGs such as GBP2 might shed light on the development of novel biomarkers and immunotherapies of ccRCC.

Guanylate-Binding protein 2b regulates the AMPK/mTOR/ULK1 signalling pathway to induce autophagy during Mycobacterium bovis infection.

Autophagic isolation and degradation of intracellular pathogens are employed by host cells as primary innate immune defense mechanisms to control intercellular M. bovis infection. In this study, RNA-Seq technology was used to obtain the total mRNA from bone marrow-derived macrophages (BMDMs) infected with M. bovis at 6 and 24 h after infection. One of the differential genes, GBP2b, was also investigated. Analysis of the significant pathway involved in GBP2b-coexpressed mRNA demonstrated that GBP2b was associated with autophagy and autophagy-related mammalian target of rapamycin (mTOR) signaling and AMP-activated protein kinase (AMPK) signaling. The results of in vivo and in vitro experiments showed significant up-regulation of GBP2b during M. bovis infection. For in vitro validation, small interfering RNA-GBP2b plasmids were transfected into BMDMs and RAW264.7 cells lines to down-regulate the expression of GBP2b. The results showed that the down-regulation of GBP2b impaired autophagy via the AMPK/mTOR/ULK1 pathway, thereby promoting the intracellular survival of M. bovis. Further studies revealed that the activation of AMPK signaling was essential for the regulation of autophagy during M. bovis infection. These findings expand the understanding of how GBP2b regulates autophagy and suggest that GBP2b may be a potential target for the treatment of diseases caused by M. bovis.

Sgh1, an SR-like Protein, Is Involved in Fungal Development, Plant Infection, and Pre-mRNA Processing in Fusarium graminearum.

Serine/arginine (SR) proteins are essential pre-mRNA splicing factors in eukaryotic organisms. Our previous studies have shownthat the unique SR-specific protein kinase Srk1 is important for RNA splicing and gene transcription in Fusarium graminearum, and interacts with two SR proteins, FgSrp1 and FgSrp2. In this study, we have identified an SR-like protein called Sgh1 in F. graminearum, which is orthologous to budding yeast paralogous Gbp2 and Hrb1. Our data have shownthat the Sgh1 is involved in vegetative growth, conidiation, sexual reproduction, DON synthesis, and plant infection. Moreover, the Sgh1 is mainly localized to the nucleus. RNA-seq analysis has shownthat the expression of over 1100 genes and the splicing efficiency in over 300 introns were affected in the Δsgh1 mutant. Although the RS domain and all three of the RRM domains are important for the Sgh1 functions, only the RS domain is responsible for its nuclear localization. Finally, we verified that the Sgh1 interacts with the unique SR-specific kinase Srk1 in F. graminearum by the yeast-two hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays. Taken together, our results have revealed that the Sgh1 regulates the fungal development, plant infection, and the pre-mRNA processing, and the RS domain regulates the function of the Sgh1 by modulating its nucleocytoplasmic shuttling.