HMGN1 loss sensitizes lung cancer cells to chemotherapy.

The high mobility group nucleosome binding (HMGN) family, constitutes a large family of non-histone protein family known to bind the acidic patch of the nucleosomes with various key cellular functions. Several studies have highlighted the pivotal roles of HMGNs in the pathogenic process of various cancer types. However, the roles of HMGN family in lung adenocarcinoma (LUAD) have not been fully elucidated. Herein, integrative analyses of multiple-omics data revealed that HMGNs frequently exhibit dysregulation in LUAD. Subsequent analysis of the clinical relevance of HMGN1 demonstrated its association with poor prognosis in LUAD and its potential as a diagnostic marker to differentiate LUAD from healthy controls. Additionally, functional enrichment analysis suggested that HMGN1 was mainly involved in DNA repair. To corroborate these findings, cellular experiments were conducted, confirming HMGN1's crucial involvement in homologous recombination repair and its potential to enhance the sensitivity of LUAD cells to standard chemotherapeutic drugs. This study proposes HMGN1 as a novel prognostic biomarker and a promising target for chemotherapy in lung adenocarcinoma.

Do Alarmins Have a Role in Multiple Myeloma?

Objective: Calprotectin (CLP), S100A6, and high mobility group nucleosome-binding protein 1 (HMGN1), known as alarmins, are involved in the pathogenesis of many tumors. In this study, we aimed to investigate the relationships of serum CLP, S100A6, and HMGN1 levels with the clinical and laboratory findings of patients with multiple myeloma (MM) and their roles in the pathogenesis of MM. Materials and Methods: We measured the serum CLP, S100A6, and HMGN1 levels of 55 newly diagnosed patients and 32 healthy controls using the sandwich enzyme-linked immunosorbent assay method. The medical records of the patients were also reviewed. Results: Serum CLP, S100A6, and HMGN1 levels were significantly decreased in MM patients compared to the control group (p=0.012, p=0.001, and p=0.030, respectively). Receiver operating characteristic analysis was used to determine diagnostic cut-off values for serum CLP, S100A6, and HMGN1 of <98 ng/mL (area under the curve [AUC]: 0.663, 95% confidence interval [CI]: 0.554-0.761, p=0.009), <1174.5 pg/mL (AUC: 0.706, 95% CI: 0.598-0.799, p=0.001), and <440.18 pg/mL (AUC: 0.640, 95% CI: 0.530-0.740, p=0.03), respectively. CLP levels were found to be statistically significantly higher in patients with light chain MM (91.58±22.57 ng/mL) compared to heavy chain MM (79.42±15.83 ng/mL) (p=0.03). A negative correlation was observed between CLP and M protein, immunoglobulin G, globulin, and beta-2 microglobulin (correlation coefficients: -0.361, -0.370, -0.279, -0.300, respectively; p=0.024, p=0.06, p=0.04, p=0.0033). Conclusion: In this study, we found that serum CLP, S100A6, and HMGN1 levels were statistically lower in patients with newly diagnosed MM compared to the control group. These results suggest that CLP may bind to the paraprotein produced by heavy chain MM in the blood, causing its blood levels to be low. Additionally, low levels of HMGN1, which is involved in DNA repair, suggest that HMGN1 may contribute to the complex genetic abnormalities found in cases of MM.

HMGN1 down-regulation in the diabetic kidney attenuates tubular cells injury and protects against renal inflammation via suppressing MCP-1 and KIM-1 expression through TLR4.

BACKGROUND: Renal tubular injury, accompanied by damaging inflammation, has been identified to drive diabetic kidney disease (DKD) toward end-stage renal disease. However, it is unclear how damage-associated molecular patterns (DAMPs) activate innate immunity to mediate tubular epithelial cell (TEC) injury, which in turn causes with subsequent sterile inflammation in diabetic kidneys. High mobility group nucleosome-binding protein 1 (HMGN1) is a novel DAMP that contributes to generating the innate immune response. In this study, we focused on determining whether HMGN1 is involved in DKD progression. METHODS: Streptozotocin (STZ)-induced diabetic mice model was established. Then we downrergulated HMGN1 expression in kidney with or without HMGN1 administration. The renal dysfunction and morphological lesions in the kidneys were evaluated. The expressions of KIM-1, MCP-1, F4/80, CD68, and HMGN1/TLR4 signaling were examined in the renal tissue. In vitro, HK2 cells were exposed in the high glucose with or without HMGN1, and further pre-incubated with TAK242 was applied to elucidate the underlying mechanism. RESULTS: We demonstrated that HMGN1 was upregulated in the tubular epithelial cells of streptozotocin (STZ)-induced type 1 and type 2 diabetic mouse kidneys compared to controls, while being positively correlated with increased TLR4, KIM-1, and MCP-1. Down-regulation of renal HMGN1 attenuated diabetic kidney injury, decreased the TLR4, KIM-1, and MCP-1 expression levels, and reduced interstitial infiltrating macrophages. However, these phenotypes were reversed after administration of HMGN1. In HK-2 cells, HMGN1 promoted the expression of KIM-1 and MCP-1 via regulating MyD88/NF-κB pathway; inhibition of TLR4 effectively diminished the in vitro response to HMGN1. CONCLUSIONS: Our study provides novel insight into HMGN1 signaling mechanisms that contribute to tubular sterile injury and low-grade inflammation in DKD. The study findings may help to develop new HMGN1-targeted approaches as therapy for immune-mediated kidney damage rather than as an anti-infection treatments.

[High mobility group nucleosome binding protein 1 (HMGN1) induces activation of mouse BV2 microglia and upregulates their pro-inflammatory mediator expression by activating TLR4/MyD88/NF-κB p65/IKK-ß signal pathway].

Objective To explore the effects and mechanism of high-mobility group nucleosome-binding protein 1 (HMGN1) on the inflammatory response of mouse BV2 microglia. Methods BV2 cells were incubated with recombinant HMGN1 at different concentrations (0, 100, 200, 500, 1000, 2000 ng/mL) for 6 hours, and the morphological changes were observed under a microscope. The mRNA levels of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), interleukin-1ß (IL-1ß) and monocyte chemotactic protein 1 (MCP-1) were detected by real time quantitative PCR. Microglial cells were then randomly divided into a control group, model group, inhibitor group and antagonist group. The cells in the model group were treated with 500 ng/mL HMGN1, while the antagonist group was treated with 500 ng/mL TAK-242 (resatorvid), a Toll-like receptor 4 (TLR4) antagonist, in addition to HMGN1. Real time quantitative PCR and immunofluorescence were used to detect the expression of M1/M2 markers in the four groups, and Western blot analysis was used to measure the protein expression levels of inducible nitric-oxide synthase (iNOS), TLR4, myeloid differentiation factor88 (MyD88), nuclear factor κB p65 (NF-κB p65) and inhibitor of NF-κB(IκB)kinase ß(IKK-ß). Results After the treatment of HMGN1, the morphology of BV2 cells changed significantly, showing an amoeba-like appearance. The mRNA levels of TNF-α, IL-6, IL-1ß and MCP-1 increased with the HMGN1 concentration, with a statistically significant difference compared to the 0 ng/mL HMGN1 group. At the same time, the mRNA level of iNOS, a M1 phenotype marker, increased with the HMGN1 concentration, while the level of CD206, a M2 phenotype marker, decreased with HMGN1 concentration, showing a statistically significant difference compared to the 0 ng/mL HMGN1 group. Compared with the model group, the mRNA level of M1 phenotypic marker iNOS in the antagonist group was significantly lower, and the level of M2 phenotypic marker CD206 was significantly higher. The results of immunofluorescence cytochemistry also showed that the expression of M1 phenotypic marker iNOS in the antagonist group was lower. The results of Western blot suggested that the protein expression levels of iNOS, TLR4, MyD88, NF-κB p65 and IKK-ß decreased significantly in the antagonist group. Conclusion HMGN1 may induce the activation of BV2 microglial cells by upregulating pro-inflammatory mediators through activating the TLR4/MyD88/NF-κB p65/IKK-ß signaling pathway.

Chromatin binding protein HMGN1 promotes HBV cccDNA transcription and replication by regulating the phosphorylation of histone 3.

BACKGROUND AND AIMS: Direct elimination of cccDNA remains a formidable obstacle due to the persistent and stable presence of cccDNA in hepatocyte nuclei. The silencing of cccDNA transcription enduringly is one of alternative strategies in the treatment of hepatitis B. Protein binding to cccDNA plays an important role in its transcriptional regulation; thus, the identification of key factors involved in this process is of great importance. APPROACHES AND RESULTS: In the present study, high mobility group nucleosome binding domain 1 (HMGN1) was screened out based on our biotin-avidin enrichment system. First, chromatin immunoprecipitation and fluorescent in situ hybridization assays confirmed the binding of HMGN1 with cccDNA in the nucleus. Second, functional experiments in HBV-infected cells showed that the promoting effect of HMGN1 on HBV transcription and replication depended on the functional region of the nucleosomal binding domain, while transfection of the HMGN1 mutant showed no influence on HBV compared with the vector. Third, further mechanistic exploration revealed that the silencing of HMGN1 increased the level of phosphorylase CLK2 and promoted H3 phosphorylation causing the reduced accessibility of cccDNA. Moreover, silenced HMGN1 was mimicked in HBV (r) cccDNA mouse model of HBV infection in vivo. The results showed that silencing HMGN1 inhibited HBV replication in vivo. CONCLUSIONS: In summary, our study identified that a host protein can bind to cccDNA and promote its transcription, providing a candidate strategy for anti-HBV targeting to interfere with the transcriptional activity of cccDNA microchromosomes.

Epigenetic Regulation of Ameloblast Differentiation by HMGN Proteins.

Dental enamel formation is coordinated by ameloblast differentiation, production of enamel matrix proteins, and crystal growth. The factors regulating ameloblast differentiation are not fully understood. Here we show that the high mobility group N (HMGN) nucleosomal binding proteins modulate the rate of ameloblast differentiation and enamel formation. We found that HMGN1 and HMGN2 proteins are downregulated during mouse ameloblast differentiation. Genetically altered mice lacking HMGN1 and HMGN2 proteins show faster ameloblast differentiation and a higher rate of enamel deposition in mice molars and incisors. In vitro differentiation of induced pluripotent stem cells to dental epithelium cells showed that HMGN proteins modulate the expression and chromatin accessibility of ameloblast-specific genes and affect the binding of transcription factors epiprofin and PITX2 to ameloblast-specific genes. Our results suggest that HMGN proteins regulate ameloblast differentiation and enamel mineralization by modulating lineage-specific chromatin accessibility and transcription factor binding to ameloblast regulatory sites.

Reactive Oxygen Species-Sensitive Biodegradable Mesoporous Silica Nanoparticles Harboring TheraVac Elicit Tumor-Specific Immunity for Colon Tumor Treatment.

Immunotherapy has revolutionized the field of cancer treatment through invigorating robust antitumor immune response. Here, we report the development of a therapeutic vaccine [consisting of high mobility group nucleosome-binding protein 1 (HMGN1), resiquimod/R848, and anti-PD-L1 (αPD-L1)]-loaded reactive oxygen species (ROS)-responsive mesoporous silica nanoparticle (MSN@TheraVac) for curative therapy of colon cancer. In MSN@TheraVac, αPD-L1 conjugated onto the surface of MSNs via a diselenide bond, which can be rapidly released under the oxidative condition of the tumor microenvironment to avert immunosuppression and effector T cell exhaustion while coloaded HMGN1 and R848 would cooperatively trigger robust tumor-infiltrating dendritic cell (TiDC) maturation and elicitation of antitumor immune responses. Indeed, MSN@TheraVac induced the maturation and activation of dendritic cells (DCs) by promoting the surface expression of CD80, CD86, and CD103 as well as the production of pro-inflammatory cytokines, including TNFα, IL-12, and IL-1ß. Importantly, treatment with intravenous MSN@TheraVac led to a complete cure of 100% of BALB/c mice bearing large colon tumors and induced the generation of tumor-specific protective memory without apparent toxicity. Thus, MSN@TheraVac provides a timely release of TheraVac for the curative treatment of colon tumors and holds potential for translation into a clinical therapy for patients with immunologically "cold" colorectal cancers. This ROS-responsive MSN platform may also be tailored for the selective delivery of other cancer vaccines for effective immunotherapy.

PM2.5 exposure aggravates kidney damage by facilitating the lipid metabolism disorder in diabetic mice.

Background: Ambient fine particulate matter ≤ 2.5 µm (PM2.5) air pollution exposure has been identified as a global health threat, the epidemiological evidence suggests that PM2.5 increased the risk of chronic kidney disease (CKD) among the diabetes mellitus (DM) patients. Despite the growing body of research on PM2.5 exposure, there has been limited investigation into its impact on the kidneys and the underlying mechanisms. Past studies have demonstrated that PM2.5 exposure can lead to lipid metabolism disorder, which has been linked to the development and progression of diabetic kidney disease (DKD). Methods: In this study, db/db mice were exposed to different dosage PM2.5 for 8 weeks. The effect of PM2.5 exposure was analysis by assessment of renal function, pathological staining, immunohistochemical (IHC), quantitative real-time PCR (qPCR) and liquid chromatography with tandem mass spectrometry (LC-MS/MS) based metabolomic analyses. Results: The increasing of Oil Red staining area and adipose differentiation related protein (ADRP) expression detected by IHC staining indicated more ectopic lipid accumulation in kidney after PM2.5 exposure, and the increasing of SREBP-1 and the declining of ATGL detected by IHC staining and qPCR indicated the disorder of lipid synthesisandlipolysis in DKD mice kidney after PM2.5 exposure. The expressions of high mobility group nucleosome binding protein 1 (HMGN1) and kidney injury molecule 1 (KIM-1) that are associated with kidney damage increased in kidney after PM2.5 exposure. Correlation analysis indicated that there was a relationship between HMGN1-KIM-1 and lipid metabolic markers. In addition, kidneys of mice were analyzed using LC-MS/MS based metabolomic analyses. PM2.5 exposure altered metabolic profiles in the mice kidney, including 50 metabolites. In conclusion the results of this study show that PM2.5 exposure lead to abnormal renal function and further promotes renal injury by disturbance of renal lipid metabolism and alter metabolic profiles.

HMGN1 enhances CRISPR-directed dual-function A-to-G and C-to-G base editing.

C-to-G base editors have been successfully constructed recently, but limited work has been done on concurrent C-to-G and A-to-G base editing. In addition, there is also limited data on how chromatin-associated factors affect the base editing. Here, we test a series of chromatin-associated factors, and chromosomal protein HMGN1 was found to enhance the efficiency of both C-to-G and A-to-G base editing. By fusing HMGN1, GBE and ABE to Cas9, we develop a CRISPR-based dual-function A-to-G and C-to-G base editor (GGBE) which is capable of converting simultaneous A and C to G conversion with substantial editing efficiency. Accordingly, the HMGN1 role shown in this work and the resulting GGBE tool further broaden the genome manipulation capacity of CRISPR-directed base editors.

Anti-TNFR2 enhanced the antitumor activity of a new HMGN1/3M-052 stimulated dendritic cell vaccine in a mouse model of colon cancer.

Immunotherapy is the new approach for cancer treatment that can be achieved through several strategies, one of which is dendritic cells (DCs) vaccine therapy. However, traditional DC vaccination lacks accurate targeting, so DC vaccine preparation needs to be optimized. Immunosuppressive CD4+Foxp3+ regulatory T cells (Tregs) in the tumor microenvironment can promote tumor immune escape. Therefore, targeting Tregs has become a strategy for tumor immunotherapy. In this study, we found that HMGN1 (N1, a dendritic cell-activating TLR4 agonist) and 3M-052 (a newly synthesized TLR7/8 agonist) synergistically stimulate DCs maturation and increase the production of proinflammatory cytokines TNFα and IL-12. In a colon cancer mice model, vaccination with N1 and 3M-052 stimulated and tumor antigen-loaded DCs combined with anti-TNFR2 inhibited tumor growth in mice, and the antitumor effect was mainly achieved through stimulation of cytotoxic CD8 T cell activation and depletion of Tregs. Overall, the combinating of DC activation by N1 and 3M-052 with inhibition of Tregs by antagonizing TNFR2 as a therapeutic strategy may represent a more effective strategy for cancer treatment.

Overexpression screen of chromosome 21 genes reveals modulators of Sonic hedgehog signaling relevant to Down syndrome.

Trisomy 21 and mutations in the Sonic hedgehog (SHH) signaling pathway cause overlapping and pleiotropic phenotypes including cerebellar hypoplasia, craniofacial abnormalities, congenital heart defects and Hirschsprung disease. Trisomic cells derived from individuals with Down syndrome possess deficits in SHH signaling, suggesting that overexpression of human chromosome 21 genes may contribute to SHH-associated phenotypes by disrupting normal SHH signaling during development. However, chromosome 21 does not encode any known components of the canonical SHH pathway. Here, we sought to identify chromosome 21 genes that modulate SHH signaling by overexpressing 163 chromosome 21 cDNAs in a series of SHH-responsive mouse cell lines. We confirmed overexpression of trisomic candidate genes using RNA sequencing in the cerebella of Ts65Dn and TcMAC21 mice, model systems for Down syndrome. Our findings indicate that some human chromosome 21 genes, including DYRK1A, upregulate SHH signaling, whereas others, such as HMGN1, inhibit SHH signaling. Individual overexpression of four genes (B3GALT5, ETS2, HMGN1 and MIS18A) inhibits the SHH-dependent proliferation of primary granule cell precursors. Our study prioritizes dosage-sensitive chromosome 21 genes for future mechanistic studies. Identification of the genes that modulate SHH signaling may suggest new therapeutic avenues for ameliorating Down syndrome phenotypes.

Acteoside alleviates UUO-induced inflammation and fibrosis by regulating the HMGN1/TLR4/TREM1 signaling pathway.

Purpose: Acteoside (Act), a phenylethanoid compound that was first isolated from mullein, has been widely used for the investigation of anti-inflammatory and anti-fibrotic effect. However, the mechanism of Act against unilateral ureteral obstruction (UUO)-mediated renal injury is largely unknown. Therefore, this study aimed to explore the effects of Act on UUO rats and possible mechanisms. Methods: A total of 20 Sprague-Dawley (SD) rats were divided randomly into three groups (n ≥ 6): (i) sham-operated group (Sham); (ii) UUO group (UUO+Saline); and (iii) UUO + Act 40 mg/kg/day, (UUO+Act); Continuous gavage administration for 2 weeks postoperatively, while the rats in Sham and UUO+saline groups were given equal amounts of saline. All rats were sacrificed after 14 days, the urine and blood samples were collected for biochemical analysis, the renal tissues were collected for pathological staining and immunohistochemistry. Correlations between individual proteins were analyzed by Pearson correlation analysis. Results: The results of renal function indexes and histopathological staining showed that Act could improve renal function by reducing serum creatinine, blood urea nitrogen and urine protein at the same time, Act could alleviate renal inflammation and fibrosis. In addition, the results of immunohistochemistry showed that Act could reduce the expression of inflammation and kidney injury-related proteins F4/80, Mcp-1, KIM-1 proteins, as well as the expression of fibrosis-related protein α-SMA and ß-catenin. More importantly, Act can also reduce the expression of HMGN1, TLR4 and TREM-1 proteins. Conclusion: These data demonstrate that Act can ameliorate UUO-induced renal inflammation and fibrosis in rats probably through triggering HMGN1/TLR4/TREM-1 pathway.

Shaking up the silence: consequences of HMGN1 antagonizing PRC2 in the Down syndrome brain.

Intellectual disability is a well-known hallmark of Down Syndrome (DS) that results from the triplication of the critical region of human chromosome 21 (HSA21). Major studies were conducted in recent years to gain an understanding about the contribution of individual triplicated genes to DS-related brain pathology. Global transcriptomic alterations and widespread changes in the establishment of neural lineages, as well as their differentiation and functional maturity, suggest genome-wide chromatin organization alterations in trisomy. High Mobility Group Nucleosome Binding Domain 1 (HMGN1), expressed from HSA21, is a chromatin remodeling protein that facilitates chromatin decompaction and is associated with acetylated lysine 27 on histone H3 (H3K27ac), a mark correlated with active transcription. Recent studies causatively linked overexpression of HMGN1 in trisomy and the development of DS-associated B cell acute lymphoblastic leukemia (B-ALL). HMGN1 has been shown to antagonize the activity of the Polycomb Repressive Complex 2 (PRC2) and prevent the deposition of histone H3 lysine 27 trimethylation mark (H3K27me3), which is associated with transcriptional repression and gene silencing. However, the possible ramifications of the increased levels of HMGN1 through the derepression of PRC2 target genes on brain cell pathology have not gained attention. In this review, we discuss the functional significance of HMGN1 in brain development and summarize accumulating reports about the essential role of PRC2 in the development of the neural system. Mechanistic understanding of how overexpression of HMGN1 may contribute to aberrant brain cell phenotypes in DS, such as altered proliferation of neural progenitors, abnormal cortical architecture, diminished myelination, neurodegeneration, and Alzheimer's disease-related pathology in trisomy 21, will facilitate the development of DS therapeutic approaches targeting chromatin.

An immunogenic cell death-related regulators classification patterns and immune microenvironment infiltration characterization in intracranial aneurysm based on machine learning.

Background: Immunogenic Cell Death (ICD) is a novel way to regulate cell death and can sufficiently activate adaptive immune responses. Its role in immunity is still emerging. However, the involvement of ICD in Intracranial Aneurysms (IA) remains unclear. This study aimed to identify biomarkers associated with ICDs and determine the relationship between them and the immune microenvironment during the onset and progression of IA. Methods: The IA gene expression profiles were obtained from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) in IA were identified and the effects of the ICD on immune microenvironment signatures were studied. Techniques like Lasso, Bayes, DT, FDA, GBM, NNET, RG, SVM, LR, and multivariate analysis were used to identify the ICD gene signatures in IA. A consensus clustering algorithm was used for conducting the unsupervised cluster analysis of the ICD patterns in IA. Furthermore, enrichment analysis was carried out for investigating the various immune responses and other functional pathways. Along with functional annotation, the weighted gene co-expression network analysis (WGCNA), protein-protein interaction (PPI) network and module construction, identification of the hub gene, and co-expression analysis were also carried out. Results: The above techniques were used for establishing the ICD gene signatures of HMGB1, HMGN1, IL33, BCL2, HSPA4, PANX1, TLR9, CLEC7A, and NLRP3 that could easily distinguish IA from normal samples. The unsupervised cluster analysis helped in identifying three ICD gene patterns in different datasets. Gene enrichment analysis revealed that the IA samples showed many differences in pathways such as the cytokine-cytokine receptor interaction, regulation of actin cytoskeleton, chemokine signaling pathway, NOD-like receptor signaling pathway, viral protein interaction with the cytokines and cytokine receptors, and a few other signaling pathways compared to normal samples. In addition, the three ICD modification modes showed obvious differences in their immune microenvironment and the biological function pathways. Eight ICD-regulators were identified and showed meaningful associations with IA, suggesting they could severe as potential prognostic biomarkers. Conclusions: A new gene signature for IA based on ICD features was created. This signature shows that the ICD pattern and the immune microenvironment are closely related to IA and provide a basis for optimizing risk monitoring, clinical decision-making, and developing novel treatment strategies for patients with IA.

HMGN1 plays a significant role in CRLF2 driven Down Syndrome leukemia and provides a potential therapeutic target in this high-risk cohort.

The genetic basis of the predisposition for Down Syndrome (DS) patients to develop cytokine receptor-like factor 2 rearranged (CRLF2r) acute lymphoblastic leukemia (ALL) is currently unknown. Genes located on chromosome 21 and expressed in hematopoietic cells are likely candidates for investigation of CRLF2r DS-ALL pathogenesis. We explored the high-mobility group nucleosome-binding protein 1 (HMGN1), located in the DS critical region, in an inducible CRISPR/Cas9 knockout (KO) xenograft model to assess the effect of HMGN1 loss of function on the leukemic burden. We demonstrated HMGN1 KO-mitigated leukemic phenotypes including hepatosplenomegaly, thrombocytopenia, and anemia, commonly observed in leukemia patients, and significantly increased survival in vivo. HMGN1 overexpression in murine stem cells and Ba/F3 cells in vitro, in combination with P2RY8-CRLF2, resulted in cytokine-independent transformation and upregulation of cell signaling pathways associated with leukemic development. Finally, in vitro screening demonstrated successful targeting of P2RY8-CRLF2 and HMGN1 co-expressing cell lines and patient samples with fedratinib (JAK2 inhibitor), and GSK-J4 (demethylase inhibitor) in combination. Together, these data provide critical insight into the development and persistence of CRLF2r DS-ALL and identify HMGN1 as a potential therapeutic target to improve outcomes and reduce toxicity in this high-risk cohort of young patients.

Spatial and Temporal Expression of High-Mobility-Group Nucleosome-Binding (HMGN) Genes in Brain Areas Associated with Cognition in Individuals with Down Syndrome.

DNA methylation and histone posttranslational modifications are epigenetics processes that contribute to neurophenotype of Down Syndrome (DS). Previous reports present strong evidence that nonhistone high-mobility-group N proteins (HMGN) are epigenetic regulators. They play important functions in various process to maintain homeostasis in the brain. We aimed to analyze the differential expression of five human HMGN genes in some brain structures and age ranks from DS postmortem brain samples. Methodology: We performed a computational analysis of the expression of human HMGN from the data of a DNA microarray experiment (GEO database ID GSE59630). Using the transformed log2 data, we analyzed the differential expression of five HMGN genes in several brain areas associated with cognition in patients with DS. Moreover, using information from different genome databases, we explored the co-expression and protein interactions of HMNGs with the histones of nucleosome core particle and linker H1 histone. Results: We registered that HMGN1 and HMGN5 were significantly overexpressed in the hippocampus and areas of prefrontal cortex including DFC, OFC, and VFC of DS patients. Age-rank comparisons between euploid control and DS individuals showed that HMGN2 and HMGN4 were overexpressed in the DS brain at 16 to 22 gestation weeks. From the BioGRID database, we registered high interaction scores of HMGN2 and HMGN4 with Hist1H1A and Hist1H3A. Conclusions: Overall, our results give strong evidence to propose that DS would be an epigenetics-based aneuploidy. Remodeling brain chromatin by HMGN1 and HMGN5 would be an essential pathway in the modification of brain homeostasis in DS.

A TNFR2 antibody by countering immunosuppression cooperates with HMGN1 and R848 immune stimulants to inhibit murine colon cancer.

Immunosuppressive CD4+Foxp3+ regulatory T cells (Tregs) promote tumor immune evasion and thus targeting of Tregs has become an strategy in cancer immunotherapy. Tumor necrosis factor receptor 2 (TNFR2) is highly expressed and important for the immunosuppressive function of Tregs in humans and mice. Thus, the benefit of targeting TNFR2 in cancer immunotherapy merits more investigation. A previous report identified a new murine monoclonal anti-TNFR2 antibody (designated TY101), which showed therapeutic efficacy in murine cancer models, but its mechanism of action was less understood. In this study, the capacity of a combination of immunostimulants to enhance the effect of this inhibitor of Tregs was investigated. We examined the efficacy of TY101 as an anti-tumor immune reagent combined with HMGN1 (N1, a dendritic cell activating TLR4 agonist) and R848 (a synthetic TLR7/8 agonist). This immunotherapeutic combination exerted synergistic antitumor effects as compared with any single treatment. The antitumor response was mainly mediated by the depletion of Tregs and stimulation of cytotoxic CD8 T cell activation. The result also suggested that the effect of TY101 was similar to that of anti-PD-L1 when used in combination with these immunostimulants. Therefore, we propose that treatment strategies of antagonizing TNFR2 on Tregs would behave as potent checkpoint inhibitors and can potentially be utilized to develop a novel antitumor immunotherapy.

Function of chromatin modifier Hmgn1 during neural crest and craniofacial development.

The neural crest is a dynamic embryonic structure that plays a major role in the formation of the vertebrate craniofacial skeleton. Neural crest formation is regulated by a complex sequence of events directed by a network of transcription factors working in concert with chromatin modifiers. The high mobility group nucleosome binding protein 1 (Hmgn1) is a nonhistone chromatin architectural protein, associated with transcriptionally active chromatin. Here we report the expression and function of Hmgn1 during Xenopus neural crest and craniofacial development. Hmgn1 is broadly expressed at the gastrula and neurula stages, and is enriched in the head region at the tailbud stage, especially in the eyes and the pharyngeal arches. Hmgn1 knockdown affected the expression of several neural crest specifiers, including sox8, sox10, foxd3, and twist1, while other genes (sox9 and snai2) were only marginally affected. The specificity of this phenotype was confirmed by rescue, where injection of Hmgn1 mRNA was able to restore sox10 expression in morphant embryos. The reduction in neural crest gene expression at the neurula stage in Hmgn1 morphant embryos correlated with a decreased number of sox10- and twist1-positive cells in the pharyngeal arches at the tailbud stage, and hypoplastic craniofacial cartilages at the tadpole stage. These results point to a novel role for Hmgn1 in the control of gene expression essential for neural crest and craniofacial development. Future work will investigate the precise mode of action of Hmgn1 in this context.

Combining an Alarmin HMGN1 Peptide with PD-L1 Blockade Results in Robust Antitumor Effects with a Concomitant Increase of Stem-Like/Progenitor Exhausted CD8+ T Cells.

The expansion of intratumoral stem-like/progenitor exhausted CD8+ T (Tstem/Tpex) cells provides a potential approach to improve the therapeutic efficacy of immune checkpoint blockade (ICB). Thus, here we demonstrate a strategy to facilitate Tstem/Tpex cell expansion by combining an alarmin high-mobility group nucleosome binding domain 1 (HMGN1) peptide with programmed death-ligand 1 (PD-L1) blockade. The antitumor effects of HMGN1, anti-PD-L1, and their combined treatment were monitored in the B16F10, LLC, Colon26, or EO771 tumor-bearing mice. The comprehensive immunologic analyses, such as high-dimensional flow cytometry, transcriptome analysis, and single-cell RNA-sequencing (scRNA-seq), were used to investigate the cellular and molecular mechanisms of antitumor immune responses after treatments. We identified the immunostimulatory domain (EPKRR SARLS AKPPA KVEAK PKK) on HMGN1 and synthesized this domain as a therapeutic peptide (minP1). Combined treatment with minP1 and PD-L1 blockade induced durable tumor regression in tumor-bearing mice. minP1 increased the number of intratumoral mature DCs enriched in immunoregulatory molecules (mregDC) and enhanced their MHC class I antigen-presenting program. minP1 also synergized with PD-L1 blockade in augmenting intratumoral Tstem/Tpex cell number. Analysis of our scRNA-seq dataset by CellPhonDB suggested potential interactions between mregDCs and Tstem/Tpex cells in tumors. Our results indicate that HMGN1 peptide (minP1) serves as an immunoadjuvant to promote effective anti-PD-L1 immunotherapy with increased Tstem/Tpex cells in tumors.

Alarmin-painted exosomes elicit persistent antitumor immunity in large established tumors in mice.

Treating large established tumors is challenging for dendritic cell (DC)-based immunotherapy. DC activation with tumor cell-derived exosomes (TEXs) carrying multiple tumor-associated antigen can enhance tumor recognition. Adding a potent adjuvant, high mobility group nucleosome-binding protein 1 (HMGN1), boosts DCs' ability to activate T cells and improves vaccine efficiency. Here, we demonstrate that TEXs painted with the functional domain of HMGN1 (TEX-N1ND) via an exosomal anchor peptide potentiates DC immunogenicity. TEX-N1ND pulsed DCs (DCTEX-N1ND) elicit long-lasting antitumor immunity and tumor suppression in different syngeneic mouse models with large tumor burdens, most notably large, poorly immunogenic orthotopic hepatocellular carcinoma (HCC). DCTEX-N1ND show increased homing to lymphoid tissues and contribute to augmented memory T cells. Importantly, N1ND-painted serum exosomes from cancer patients also promote DC activation. Our study demonstrates the potency of TEX-N1ND to strengthen DC immunogenicity and to suppress large established tumors, and thus provides an avenue to improve DC-based immunotherapy.