The migration behavior of human glioblastoma cells is influenced by the redox-sensitive human macrophage capping protein CAPG

Tumor vascular disrupting agent 5,6-dimethylxanthenone-4-acetic acid (DMXAA): Suppresses macrophage capping protein beyond STING activation

The vascular disrupting agent (VDA) 5,6-dimethylxanthenone-4-acetic acid (DMXAA) induces apoptosis in vascular endothelial cells and leads to tumor hemorrhagic necrosis. While DMXAA has been proven to be a potent agonist of murine stimulator of interferon genes (mSTING), it has little effect on human-STING (hSTING). This species selectivity of DMXAA may explain its effectiveness against solid tumors in mice and its failure in clinical trials. However, DMXAA did reduce tumor volume in some patients during clinical trials. These paradoxical results have prompted us to investigate the anti-tumor mechanism of DMXAA beyond STING in the destruction of tumor vasculature in humans. In this study, we demonstrated that DMXAA binds to both human and mouse macrophage capping protein (CapG), with a KD of 5.839 μM for hCapG and a KD of 2.867 μM for mCapG, as determined by surface plasmon resonance (SPR) analysis. Homology modeling and molecular docking analysis of hCapG indicated that the critical residues involved in the hydrogen bond interaction of DMXAA with hCapG were Arg153, Thr151, and GLN141, Asn234. In addition, electrostatic pi-cation interaction occurred between DMXAA and hCapG. Further functional studies revealed that CapG protein plays a crucial role in the effects of DMXAA on human umbilical endothelial vein cell (HUEVC) angiogenesis and migration, as well as the expression of cytoskeletal proteins actin and tubulin, and the invasion of A549 lung adenocarcinoma cells. Our study has originally uncovered a novel cross-species pathway underlying the antitumor vascular disruption of DMXAA extends beyond STING activation. This finding deepens our understanding of the multifaceted actions of flavonoid VDAs in animal models and in clinical settings, and may provide insights for the precise therapy of DMXAA based on the biomarker CapG protein.

CAPG is a novel biomarker for early gastric cancer and is involved in the Wnt/β-catenin signaling pathway

Past studies have shown that the Gelsolin-like actin-capping protein (CAPG) regulates cell migration and proliferation and is strongly associated with tumor progression. We present the first study of the mechanism of action of CAPG in early gastric cancer (EGC). We demonstrate that CAPG expression is upregulated in gastric cancer (GC) especially EGC. CAPG promotes GC proliferation, migration, invasion, and metastasis in vivo and in vitro. More importantly, CAPG plays a role in GC by involving the Wnt/β-catenin signaling pathway. Our findings suggest that CAPG may function as a novel biomarker for EGC.

Modulation of recovery from neonatal hyperoxic lung injury by sex as a biological variable

Recovery from lung injury during the neonatal period requires the orchestration of many biological pathways. The modulation of such pathways can drive the developing lung towards proper repair or persistent maldevelopment that can lead to a disease phenotype. Sex as a biological variable can regulate these pathways differently in the male and female lung exposed to neonatal hyperoxia. In this study, we assessed the contribution of cellular diversity in the male and female neonatal lung following injury. Our objective was to investigate sex and cell-type specific transcriptional changes that drive repair or persistent injury in the neonatal lung and delineate the alterations in the immune-endothelial cell communication networks using single cell RNA sequencing (sc-RNAseq) in a murine model of hyperoxic injury. We generated transcriptional profiles of >55,000 cells isolated from the lungs of postnatal day 1 (PND 1; pre-exposure), PND 7, and PND 21neonatal male and female C57BL/6 mice exposed to 95 % FiO2 between PND 1-5 (saccular stage of lung development). We show the presence of sex-based differences in the transcriptional states of lung endothelial and immune cells at PND 1 and PND 21. Furthermore, we demonstrate that biological sex significantly influences the response to injury, with a greater number of differentially expressed genes showing sex-specific patterns than those shared between male and female lungs. Pseudotime trajectory analysis highlighted genes needed for lung development that were altered by hyperoxia. Finally, we show intercellular communication between endothelial and immune cells at saccular and alveolar stages of lung development with sex-based biases in the crosstalk and identify novel ligand-receptor pairs. Our findings provide valuable insights into the cell diversity, transcriptional state, developmental trajectory, and cell-cell communication underlying neonatal lung injury, with implications for understanding lung development and possible therapeutic interventions while highlighting the crucial role of sex as a biological variable.

The Golgi stacking protein GRASP55 is targeted by the natural compound prodigiosin

BACKGROUND

The bacterial secondary metabolite prodigiosin has been shown to exert anticancer, antimalarial, antibacterial and immunomodulatory properties. With regard to cancer, it has been reported to affect cancer cells but not non-malignant cells, rendering prodigiosin a promising lead compound for anticancer drug discovery. However, a direct protein target has not yet been experimentally identified.

METHODS

We used mass spectrometry-based thermal proteome profiling in order to identify target proteins of prodigiosin. For target validation, we employed a genetic knockout approach and electron microscopy.

RESULTS

We identified the Golgi stacking protein GRASP55 as target protein of prodigiosin. We show that prodigiosin treatment severely affects Golgi morphology and functionality, and that prodigiosin-dependent cytotoxicity is partially reduced in GRASP55 knockout cells. We also found that prodigiosin treatment results in decreased cathepsin activity and overall blocks autophagic flux, whereas co-localization of the autophagosomal marker LC3 and the lysosomal marker LAMP1 is clearly promoted. Finally, we observed that autophagosomes accumulate at GRASP55-positive structures, pointing towards an involvement of an altered Golgi function in the autophagy-inhibitory effect of this natural compound.

CONCLUSION

Taken together, we propose that prodigiosin affects autophagy and Golgi apparatus integrity in an interlinked mode of action involving the regulation of organelle alkalization and the Golgi stacking protein GRASP55. Video Abstract.

Modulation of Recovery from Neonatal Hyperoxic Lung Injury by Sex as a Biological Variable

Recovery from lung injury during the neonatal period requires the orchestration of many biological pathways. The modulation of such pathways can drive the developing lung towards proper repair or persistent maldevelopment that can lead to a disease phenotype. Sex as a biological variable can regulate these pathways differently in the male and female lung exposed to neonatal hyperoxia. In this study, we assessed the contribution of cellular diversity in the male and female neonatal lung following injury. Our objective was to investigate sex and cell-type specific transcriptional changes that drive repair or persistent injury in the neonatal lung and delineate the alterations in the immune-endothelial cell communication networks using single cell RNA sequencing (sc-RNAseq) in a murine model of hyperoxic injury. We generated transcriptional profiles of >55,000 cells isolated from the lungs of postnatal day 1 (PND 1) and postnatal day 21 (PND 21) neonatal male and female C57BL/6 mice exposed to 95% FiO 2 between PND 1-5 (saccular stage of lung development). We show the presence of sex-based differences in the transcriptional states of lung endothelial and immune cells at PND 1 and PND 21. Furthermore, we demonstrate that biological sex significantly influences the response to injury, with a greater number of differentially expressed genes showing sex-specific patterns than those shared between male and female lungs. Pseudotime trajectory analysis highlighted genes needed for lung development that were altered by hyperoxia. Finally, we show intercellular communication between endothelial and immune cells at saccular and alveolar stages of lung development with sex-based biases in the crosstalk and identify novel ligand-receptor pairs. Our findings provide valuable insights into the cell diversity, transcriptional state, developmental trajectory, and cell-cell communication underlying neonatal lung injury, with implications for understanding lung development and possible therapeutic interventions while highlighting the crucial role of sex as a biological variable.

Tumor Suppressor Role of INPP4B in Chemoresistant Retinoblastoma

The chemotherapy of retinoblastoma (RB), a malignant ocular childhood disease, is often limited by the development of resistance against commonly used drugs. We identified inositol polyphosphate 4-phosphatase type II (INPP4B) as a differentially regulated gene in etoposide-resistant RB cell lines, potentially involved in the development of RB resistances. INPP4B is controversially discussed as a tumor suppressor and an oncogenic driver in various cancers, but its role in retinoblastoma in general and chemoresistant RB in particular is yet unknown. In the study presented, we investigated the expression of INPP4B in RB cell lines and patients and analyzed the effect of INPP4B overexpression on etoposide resistant RB cell growth in vitro and in vivo. INPP4B mRNA levels were significantly downregulated in RB cells lines compared to the healthy human retina, with even lower expression levels in etoposide-resistant compared to the sensitive cell lines. Besides, a significant increase in INPP4B expression was observed in chemotherapy-treated RB tumor patient samples compared to untreated tumors. INPP4B overexpression in etoposide-resistant RB cells resulted in a significant reduction in cell viability with reduced growth, proliferation, anchorage-independent growth, and in ovo tumor formation. Caspase-3/7-mediated apoptosis was concomitantly increased, suggesting a tumor suppressive role of INPP4B in chemoresistant RB cells. No changes in AKT signaling were discernible, but p-SGK3 levels increased following INPP4B overexpression, indicating a potential regulation of SGK3 signaling in etoposide-resistant RB cells. RNAseq analysis of INPP4B overexpressing, etoposide-resistant RB cell lines revealed differentially regulated genes involved in cancer progression, mirroring observed in vitro and in vivo effects of INPP4B overexpression and strengthening INPP4B’s importance for cell growth control and tumorigenicity.

Synovial Fluid in Knee Osteoarthritis Extends Proinflammatory Niche for Macrophage Polarization

Macrophage polarization is a steering factor of osteoarthritis (OA) progression. Synovial fluid (SF) obtained from OA patients with different Kellgren-Lawrence grades (KL grades) holds several proinflammatory factors and was hypothesized to induce macrophage differentiation and polarization by providing the needed microenvironment. U937 cells and peripheral-blood-mononuclear-cell-derived monocytes (PBMC-derived CD14+ cells) were induced with SFs of progressive KL grades for 48 h, and the status of the differentiated cells was evaluated by cell surface markers representing M1 and M2 macrophage phenotypes. Functional viability assessment of the differentiated cells was performed by cytokine estimation. The fraction of macrophages and their phenotypes were estimated by immunophenotyping of SF-isolated cells of different KL grades. A grade-wise proteome analysis of SFs was performed in search of the factors which are influential in macrophage differentiation and polarization. In the assay on U937 cells, induction with SF of KL grade III and IV showed a significant increase in M1 type (CD86+). The percentage of M2 phenotype (CD163+) was significantly higher after the induction with SF of KL grade II. A Significantly higher M1/M2 ratio was estimated in the cells induced with KL grade III and IV. The cell differentiation pattern in the assay on PBMC-derived CD14+ cells showed a grade-wise decline in both M1 (CD11C+, CD86+) and M2 phenotype (CD163+). Cytokine estimation specific to M1 (TNF-α, IL-6, IL-1β, IFN-γ) and M2 (IL-4 and IL-10) macrophages corelated with the differentiation pattern in the U937 cell assay, while it did not reveal any significant changes in the PBMC-derived CD14+ cells assay. SF cells' immunophenotyping showed the highest percentage of CD14+ macrophages in KL grade II; CD86+ and CD163+ cells were minimal in all KL grades' SFs. The proteome analysis revealed significantly expressed MIF, CAPG/MCP, osteopontin, and RAS-related RAB proteins in KL grade III and IV samples, which are linked with macrophages' movement, polarization, and migration-behavior. In conclusion, this study demonstrated that SF in OA joints acts as a niche and facilitates M1 phenotype polarization by providing a proinflammatory microenvironment.

Single-cell RNA-sequencing of zebrafish hair cells reveals novel genes potentially involved in hearing loss

Hair cells play key roles in hearing and balance, and hair cell loss would result in hearing loss or vestibular dysfunction. Cellular and molecular research in hair cell biology provides us a better understanding of hearing and deafness. Zebrafish, owing to their hair cell-enriched organs, have been widely applied in hair cell-related research worldwide. Similar to mammals, zebrafish have inner ear hair cells. In addition, they also have lateral line neuromast hair cells. These different types of hair cells vary in morphology and function. However, systematic analysis of their molecular characteristics remains lacking. In this study, we analyzed the GFP+ cells isolated from Tg(Brn3c:mGFP) larvae with GFP expression in all hair cells using single-cell RNA-sequencing (scRNA-seq). Three subtypes of hair cells, namely macula hair cell (MHC), crista hair cell (CHC), and neuromast hair cell (NHC), were characterized and validated by whole-mount in situ hybridization analysis of marker genes. The hair cell scRNA-seq data revealed hair cell-specific genes, including hearing loss genes that have been identified in humans and novel genes potentially involved in hair cell formation and function. Two novel genes were discovered to specifically function in NHCs and MHCs, corresponding to their specific expression in NHCs and MHCs. This study allows us to understand the specific genes in hair cell subpopulations of zebrafish, which will shed light on the genetics of both human vestibular and cochlear hair cell function.

Overexpression of CAPG Is Associated with Poor Prognosis and Immunosuppressive Cell Infiltration in Ovarian Cancer

Historically, immunotherapies have only resulted in a partial response from patients with advanced ovarian cancer, resulting in poor clinical efficacy. A full understanding of immune-related gene expression and immunocyte infiltration in ovarian cancer would be instrumental for the improved implementation of immunotherapy. The Capping Actin Protein, Gelsolin-Like (CAPG) gene encodes an actin-regulatory protein, which plays important roles in tumor progression and immune regulation. This study is aimed at identifying the potential therapeutic and prognostic roles of CAPG in ovarian cancer. CAPG expression and clinical information were investigated in the data collected from TCGA, Oncomine, GEPIA, UALCAN, and Kaplan-Meier plotter. CAPG coexpression networks were evaluated by LinkedOmics, GeneMANIA, and NetworkAnalyst. The correlation of CAPG with immune infiltrates was analyzed via TIMER, ImmuCellAI, and GEPIA. Our result showed that patients with high tumoral CAPG expression had significantly shorter 5-year overall survival. Functional enrichment analysis indicated that CAPG-related phenotypes were largely involved in inflammatory response, chemokine and cytokine signaling, cell adhesion, and Toll-like receptor signaling pathways. CAPG expression was positively correlated with infiltrating levels of regulatory T cells (Tregs), tumor-associated macrophages (TAMs), and exhausted T cells (Texs) while being negatively correlated with infiltrating levels of natural killer T cells (NKTs) and neutrophils in ovarian cancer. Moreover, the expression of FOXP3, CD25, CD127, CCR8, and TGFβ in respect to Tregs; CCL2 and CD68 in respect to TAM; CD163, VSIG4, and MS4A4A in respect to M2 macrophages; CD33 and CD11b in respect to myeloid-derived suppressor cells (MDSCs); and PD1, CTLA4, LAG3, TIM3, GZMB, 2B4, and TIGIT in respect to Texs was significantly correlated with CAPG expression in ovarian cancer. These findings suggest that CAPG may contribute to the immunosuppressive tumor microenvironment in ovarian cancer, leading to an exhausted T cell phenotype and tumor progression. Therefore, CAPG can be used as a potential biomarker for determining prognosis and immunotherapy effectiveness in ovarian cancer.

Glutaredoxin 2 promotes SP-1-dependent CSPG4 transcription and migration of wound healing NG2 glia and glioma cells: Enzymatic Taoism

Redox regulation of specific cysteines via oxidoreductases of the thioredoxin family is increasingly being recognized as an important signaling pathway. Here, we demonstrate that the cytosolic isoform of the vertebrate-specific oxidoreductase Glutaredoxin 2 (Grx2c) regulates the redox state of the transcription factor SP-1 and thereby its binding affinity to both the promoter and an enhancer region of the CSPG4 gene encoding chondroitin sulfate proteoglycan nerve/glial antigen 2 (NG2). This leads to an increased number of NG2 glia during in vitro oligodendroglial differentiation and promotes migration of these wound healing cells. On the other hand, we found that the same mechanism also leads to increased invasion of glioma tumor cells. Using in vitro (human cell lines), ex vivo (mouse primary cells), and in vivo models (zebrafish), as well as glioblastoma patient tissue samples we provide experimental data highlighting the Yin and Yang of redox signaling in the central nervous system and the enzymatic Taoism of Grx2c.

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CSPG4 promoter binding of the transcription factor SP-1 depends on glutaredoxin 2

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Cytosolic glutaredoxin 2 promotes oligodendrocyte differentiation into NG2 glia

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Migration and wound healing capacity of NG2 glia is increased by glutaredoxin 2

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Glutaredoxin 2 increases invasion of human glioblastoma cells in vitro and in vivo

Targeting AVIL, a New Cytoskeleton Regulator in Glioblastoma

Glioblastoma (GBM) is the most common adult neural malignancy and the deadliest. The standard of care is optimal, safe, cytoreductive surgery followed by combined radiation therapy and alkylating chemotherapy with temozolomide. Recurrence is common and therapeutic options in the recurrent setting are limited. The dismal prognosis of GBM has led to novel treatments being a serious roadblock in the field, with most new treatments failing to show efficacy. Targeted therapies have shown some success in many cancers, but GBM remains one of the most difficult to treat, especially in recurrence. New chemotherapeutic directions need to be explored, possibly expanding the targeted chemotherapy spectrum in previously unforeseen ways. In this perspective paper, we will explain why AVIL, an actin-binding protein recently found to be overexpressed in GBM and a driving force for GBM, could prove versatile in the fight against cancer. By looking at AVIL and its potential to regulate FOXM1 and LIN28B, we will be able to highlight a way to improve outcomes for GBM patients who normally have very little hope.

Heme Oxygenase-1 Predicts Risk Stratification and Immunotherapy Efficacy in Lower Grade Gliomas

Background: Gliomas are the most common tumors in human brains with unpleasing outcomes. Heme oxygenase-1 (HMOX1, HO-1) was a potential target for human cancers. However, their relationship remains incompletely discussed. Methods: We employed a total of 952 lower grade glioma (LGG) patients from TCGA and CGGA databases, and 29 samples in our hospital for subsequent analyses. Expression, mutational, survival, and immune profiles of HMOX1 were comprehensively evaluated. We constructed a risk signature using the LASSO Cox regression model, and further generated a nomogram model to predict survival of LGG patients. Single-cell transcriptomic sequencing data were also employed to investigated the role of HMOX1 in cancer cells. Results: We found that HMOX1 was overexpressed and was related to poorer survival in gliomas. HMOX1-related genes (HRGs) were involved in immune-related pathways. Patients in the high-risk group exhibited significantly poorer overall survival. The risk score was positively correlated with the abundance of resting memory CD4+ T cells, M1, M2 macrophages, and activated dendritic cells. Additionally, immunotherapy showed potent efficacy in low-risk group. And patients with lower HMOX1 expression were predicted to have better response to immunotherapies, suggesting that immunotherapies combined with HMOX1 inhibition may execute good responses. Moreover, significant correlations were found between HMOX1 expression and single-cell functional states including angiogenesis, hypoxia, and metastasis. Finally, we constructed a nomogram which could predict 1-, 3-, and 5-year survival in LGG patients. Conclusion: HMOX1 is involved in immune infiltration and predicts poor survival in patients with lower grade glioma. Importantly, HMOX1 were related to oncological functional states including angiogenesis, hypoxia, and metastasis. A nomogram integrated with the risk signature was obtained to robustly predict glioma patient outcomes, with the potential to guide clinical decision-making.