High-mobility group nucleosome-binding protein 1 acts as an alarmin and is critical for lipopolysaccharide-induced immune responses

A recent perspective on designing tumor vaccines for tumor immunology

With the rapid development of immunotherapy, therapeutic tumor vaccines, which aim to enhance the immunogenicity of tumor cells and activate the patient's immune system to kill tumor cells, as well as eliminate or inhibit tumor growth, have drawn increasing attention in the field of tumor therapy. However, due to the lack of immune cell infiltration, low immunogenicity, immune escape and other problems, the efficacy of tumor vaccine is often limited. Researchers have developed a variety of strategies to enhance tumor immune recognition, such as improving the immunogenicity of tumor antigens, selecting a suitable vaccine platform, or combining tumor vaccines with other anticancer treatments. In this review, we will deliberate on how to overcome the problem of therapeutic tumor vaccines, and discuss the up-to-date progress and achievements in the tumor vaccine development, as well as their future in cancer treatment.

Research Progress on Dendritic Cells in Hepatocellular Carcinoma Immune Microenvironments

Dendritic cells (DCs) are antigen-presenting cells that play a crucial role in initiating immune responses by cross-presenting relevant antigens to initial T cells. The activation of DCs is a crucial step in inducing anti-tumor immunity. Upon recognition and uptake of tumor antigens, activated DCs present these antigens to naive T cells, thereby stimulating T cell-mediated immune responses and enhancing their ability to attack tumors. It is particularly noted that DCs are able to cross-present foreign antigens to major histocompatibility complex class I (MHC-I) molecules, prompting CD8+ T cells to proliferate and differentiate into cytotoxic T cells. In the malignant progression of hepatocellular carcinoma (HCC), the inactivation of DCs plays an important role, and the activation of DCs is particularly important in anti-HCC immunotherapy. In this review, we summarize the mechanisms of DCs activation in HCC, the involved regulatory factors and strategies to activate DCs in HCC immunotherapy. It provides a basis for the study of HCC immunotherapy through DCs activation.

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.

Bactericidal/permeability-increasing protein instructs dendritic cells to elicit Th22 cell response

Neutrophil-derived bactericidal/permeability-increasing protein (BPI) is known for its bactericidal activity against gram-negative bacteria and neutralization of lipopolysaccharide. Here, we define BPI as a potent activator of murine dendritic cells (DCs). As shown in GM-CSF-cultured, bone-marrow-derived cells (BMDCs), BPI induces a distinct stimulation profile including IL-2, IL-6, and tumor necrosis factor expression. Conventional DCs also respond to BPI, while M-CSF-cultivated or peritoneal lavage macrophages do not. Subsequent to BPI stimulation of BMDCs, CD4+ T cells predominantly secrete IL-22 and, when naive, preferentially differentiate into T helper 22 (Th22) cells. Congruent with the tissue-protective properties of IL-22 and along with impaired IL-22 induction, disease severity is significantly increased during dextran sodium sulfate-induced colitis in BPI-deficient mice. Importantly, physiological diversification of intestinal microbiota fosters BPI-dependent IL-22 induction in CD4+ T cells derived from mesenteric lymph nodes. In conclusion, BPI is a potent activator of DCs and consecutive Th22 cell differentiation with substantial relevance in intestinal homeostasis.

LTX-315 triggers anticancer immunity by inducing MyD88-dependent maturation of dendritic cells

LTX-315 is a synthetic cationic oncolytic peptide with potent anticancer activity but limited toxicity for non-malignant cells. LTX-315 induces both immunogenic tumor cell death and generation of tumor-specific immune responses in multiple experimental tumor models. Given the central role of dendritic cell (DC) maturation in the induction of antigen-specific immunity, we investigated the effect of LTX-315 treatment on the maturation of tumor-infiltrating DCs (TiDCs) and the generation of anti-melanoma immunity. We found that LTX-315 treatment induces the maturation of DCs, both indirectly through the release of cancer cell-derived damage-associated molecular patterns (DAMPs)/alarmins and nucleic acids (DNA and RNA) capable of triggering distinct Toll-like receptor (TLR) signaling, and, directly by activating TLR7. The latter results in the ignition of multiple intracellular signaling pathways that promotes DC maturation, including NF-κB, mitogen activated protein kinases (MAPKs), and inflammasome signaling, as well as increased type 1 interferon production. Critically, the effects of LTX-315 on DCs the consequent promotion of anti-melanoma immunity depend on the cytosolic signal transducer myeloid differentiation response gene 88 (MyD88). These results cast light on the mechanisms by which LTX-315 induces DC maturation and hence elicits anticancer immunity, with important implications for the use of LTX-315 as an anticancer immunotherapeutic.

Glioma: bridging the tumor microenvironment, patient immune profiles and novel personalized immunotherapy

Glioma is the most common primary brain tumor, characterized by a consistently high patient mortality rate and a dismal prognosis affecting both survival and quality of life. Substantial evidence underscores the vital role of the immune system in eradicating tumors effectively and preventing metastasis, underscoring the importance of cancer immunotherapy which could potentially address the challenges in glioma therapy. Although glioma immunotherapies have shown promise in preclinical and early-phase clinical trials, they face specific limitations and challenges that have hindered their success in further phase III trials. Resistance to therapy has been a major challenge across many experimental approaches, and as of now, no immunotherapies have been approved. In addition, there are several other limitations facing glioma immunotherapy in clinical trials, such as high intra- and inter-tumoral heterogeneity, an inherently immunosuppressive microenvironment, the unique tissue-specific interactions between the central nervous system and the peripheral immune system, the existence of the blood-brain barrier, which is a physical barrier to drug delivery, and the immunosuppressive effects of standard therapy. Therefore, in this review, we delve into several challenges that need to be addressed to achieve boosted immunotherapy against gliomas. First, we discuss the hurdles posed by the glioma microenvironment, particularly its primary cellular inhabitants, in particular tumor-associated microglia and macrophages (TAMs), and myeloid cells, which represent a significant barrier to effective immunotherapy. Here we emphasize the impact of inducing immunogenic cell death (ICD) on the migration of Th17 cells into the tumor microenvironment, converting it into an immunologically "hot" environment and enhancing the effectiveness of ongoing immunotherapy. Next, we address the challenge associated with the accurate identification and characterization of the primary immune profiles of gliomas, and their implications for patient prognosis, which can facilitate the selection of personalized treatment regimens and predict the patient's response to immunotherapy. Finally, we explore a prospective approach to developing highly personalized vaccination strategies against gliomas, based on the search for patient-specific neoantigens. All the pertinent challenges discussed in this review will serve as a compass for future developments in immunotherapeutic strategies against gliomas, paving the way for upcoming preclinical and clinical research endeavors.

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.

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-1β. 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.

Leveraging osteoclast genetic regulatory data to identify genes with a role in osteoarthritis

There has been a growing interest in the role of the subchondral bone and its resident osteoclasts in the progression of osteoarthritis (OA). A recent genome-wide association study (GWAS) identified 100 independent association signals for OA traits. Most of these signals are led by noncoding variants, suggesting that genetic regulatory effects may drive many of the associations. We have generated a unique human osteoclast-like cell-specific expression quantitative trait locus (eQTL) resource for studying the genetics of bone disease. Considering the potential role of osteoclasts in the pathogenesis of OA, we performed an integrative analysis of this dataset with the recently published OA GWAS results. Summary data-based Mendelian randomization (SMR) and colocalization analyses identified 38 genes with a potential role in OA, including some that have been implicated in Mendelian diseases with joint/skeletal abnormalities, such as BICRA, EIF6, CHST3, and FBN2. Several OA GWAS signals demonstrated colocalization with more than one eQTL peak, including at 19q13.32 (hip OA with BCAM, PRKD2, and BICRA eQTL). We also identified a number of eQTL signals colocalizing with more than one OA trait, including FAM53A, GCAT, HMGN1, MGAT4A, RRP7BP, and TRIOBP. An SMR analysis identified 3 loci with evidence of pleiotropic effects on OA-risk and gene expression: LINC01481, CPNE1, and EIF6. Both CPNE1 and EIF6 are located at 20q11.22, a locus harboring 2 other strong OA candidate genes, GDF5 and UQCC1, suggesting the presence of an OA-risk gene cluster. In summary, we have used our osteoclast-specific eQTL dataset to identify genes potentially involved with the pathogenesis of OA.

HMGB1 and Toll-like receptors: potential therapeutic targets in autoimmune diseases

HMGB1, a nucleoprotein, is expressed in almost all eukaryotic cells. During cell activation and cell death, HMGB1 can function as an alarm protein (alarmin) or damage-associated molecular pattern (DAMP) and mediate early inflammatory and immune response when it is translocated to the extracellular space. The binding of extracellular HMGB1 to Toll-like receptors (TLRs), such as TLR2 and TLR4 transforms HMGB1 into a pro-inflammatory cytokine, contributing to the occurrence and development of autoimmune diseases. TLRs, which are members of a family of pattern recognition receptors, can bind to endogenous DAMPs and activate the innate immune response. Additionally, TLRs are key signaling molecules mediating the immune response and play a critical role in the host defense against pathogens and the maintenance of immune balance. HMGB1 and TLRs are reported to be upregulated in several autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, type 1 diabetes mellitus, and autoimmune thyroid disease. The expression levels of HMGB1 and some TLRs are upregulated in tissues of patients with autoimmune diseases and animal models of autoimmune diseases. The suppression of HMGB1 and TLRs inhibits the progression of inflammation in animal models. Thus, HMGB1 and TLRs are indispensable biomarkers and important therapeutic targets for autoimmune diseases. This review provides comprehensive strategies for treating or preventing autoimmune diseases discovered in recent years.

Development of a novel modified vaccine (TheraVacM) for curative treatment of mouse solid tumors

Monotherapy with immune checkpoint blockade (ICB) antibodies (anti-CTLA4 and anti-PD1/PDL-1) is only effective for 20% to 30% of patients with certain cancers. Patients with cancers harboring few effector T cells (Teffs) are insensitive to ICB therapy. The lack of tumor-specific Teffs is predominantly caused by the paralysis of tumor-infiltrating dendritic cells (TiDCs) resulting from immunosuppression in the tumor microenvironment. We have identified a potent combination of high mobility group nucleosome binding domain 1 (HMGN1, N1) and fibroblast stimulating lipopeptide-1 (FSL-1) that can synergistically trigger maturation of both mouse and human DCs. Accordingly, we designed a combinational anti-cancer immunotherapy with two arms: an immune-activating arm consisting of N1 and FSL-1 to stimulate the generation of Teffs by triggering full maturation of TiDCs, and an ICB arm using anti-PDL-1 or anti-CTLA4 to prevent Teffs from being silenced in the tumor tissue. This combinational immunotherapeutic vaccination regimen dubbed modified TheraVac (TheraVacM) has proved particularly effective as it cured 100% of mice bearing established ectopic CT26 colon and RENCA kidney tumors. The resultant tumor-free mice were resistant to subsequent re-challenge with the same tumors, indicating the generation of long-term tumor specific protective immunity. Since the immune-activating arm also induces full maturation of human DCs, and anti-PDL-1 or anti-CTLA4 have been FDA-approved, this combinational immunotherapy has the potential to be an effective clinical therapy for patients with solid tumors.

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.

Regression and Eradication of Triple-Negative Breast Carcinoma in 4T1 Mouse Model by Combination Immunotherapies

Triple-negative breast carcinoma (TNBC) is one of the most aggressive types of solid-organ cancers. While immune checkpoint blockade (ICB) therapy has significantly improved outcomes in certain types of solid-organ cancers, patients with immunologically cold TNBC are afforded only a modest gain in survival by the addition of ICB to systemic chemotherapy. Thus, it is urgently needed to develop novel effective therapeutic approaches for TNBC. Utilizing the 4T1 murine model of TNBC, we developed a novel combination immunotherapeutic regimen consisting of intratumoral delivery of high-mobility group nucleosome binding protein 1 (HMGN1), TLR2/6 ligand fibroblast-stimulating lipopeptide (FSL-1), TLR7/8 agonist (R848/resiquimod), and CTLA-4 blockade. We also investigated the effect of adding SX682, a small-molecule inhibitor of CXCR1/2 known to reduce MDSC trafficking to tumor microenvironment, to our therapeutic approach. 4T1-bearing mice responded with significant tumor regression and tumor elimination to our therapeutic combination regimen. Mice with complete tumor regressions did not recur and became long-term survivors. Treatment with HMGN1, FSL-1, R848, and anti-CTLA4 antibody increased the number of infiltrating CD4+ and CD8+ effector/memory T cells in both tumors and draining lymph nodes and triggered the generation of 4T1-specific cytotoxic T lymphocytes (CTLs) in the draining lymph nodes. Thus, we developed a potentially curative immunotherapeutic regimen consisting of HMGN1, FSL-1, R848, plus a checkpoint inhibitor for TNBC, which does not rely on the administration of chemotherapy, radiation, or exogenous tumor-associated antigen(s).

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 β-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.

Expression, tumor immune infiltration, and prognostic impact of HMGs in gastric cancer

Background

In the past decade, considerable research efforts on gastric cancer (GC) have been expended, however, little advancement has been made owing to the lack of effective biomarkers and treatment options. Herein, we aimed to examine the levels of expression, mutations, and clinical relevance of HMGs in GC to provide sufficient scientific evidence for clinical decision-making and risk management.

Methods

GC samples were obtained from The Cancer Genome Atlas (TCGA). University of California Santa Cruz (UCSC) XENA, Human Protein Atlas (HPA), Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier Plotter, cBioPortal, GeneMANIA, STRING, LinkedOmics, and DAVID databases were employed. The "ggplot2" package in the R software (×64 3.6.3) was used to thoroughly analyze the effects of HMGs. qRT-PCR was performed to assess HMG levels in GC cell lines.

Results

A total of 375 GC tissues and 32 paraneoplastic tissues were analyzed. The levels of HMGA1, HMGA2, HMGB1, HMGB2, HMGB3, HMGN1, HMGN2, and HMGN4 expression were increased in GC tissues relative to normal gastric tissues. HMGA1, HMGA2, HMGB1, HMGB2, and HMGB3 were highly expressed in GC cell lines. The OS was significantly different in the group showing low expressions of HMGA1, HMGA2, HMGB1, HMGB2, HMGB3, HMGN2, HMGN3, and HMGN5. There was a significant difference in RFS between the groups with low HMGA2, HMGB3, and high HMGN2 expression. The levels of HMGA2, HMGB3, and HMGN1 had a higher accuracy for prediction to distinguish GC from normal tissues (AUC value > 0.9). HMGs were tightly associated with immune infiltration and tumor immune escape and antitumor immunity most likely participates in HMG-mediated oncogenesis in GC. GO and KEGG enrichment analyses showed that HMGs played a vital role in the cell cycle pathway.

Conclusions

Our results strongly suggest a vital role of HMGs in GC. HMGA2 and HMGB3 could be potential markers for prognostic prediction and treatment targets for GC by interrupting the cell cycle pathway. Our findings might provide renewed perspectives for the selection of prognostic biomarkers among HMGs in GC and may contribute to the determination of the optimal strategy for the treatment of these patients.

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.

Tumor-Derived Membrane Vesicles: A Promising Tool for Personalized Immunotherapy

Tumor-derived membrane vesicles (TDMVs) are non-invasive, chemotactic, easily obtained characteristics and contain various tumor-borne substances, such as nucleic acid and proteins. The unique properties of tumor cells and membranes make them widely used in drug loading, membrane fusion and vaccines. In particular, personalized vectors prepared using the editable properties of cells can help in the design of personalized vaccines. This review focuses on recent research on TDMV technology and its application in personalized immunotherapy. We elucidate the strengths and challenges of TDMVs to promote their application from theory to clinical practice.

Tumor-derived exosomes in the cancer immune microenvironment and cancer immunotherapy

Tumor-derived exosomes (TDEs) are key immune regulators in the tumor microenvironment. They have been shown to reshape the immune microenvironment and prevent antitumor immune responses via their immunosuppressive cargo, thereby determining responsiveness to cancer therapy. By delivering suppressive cargo to the immune cells, TDEs directly or indirectly influence the functions and antitumor activities of immune cells. TDE-based therapy is emerging as a cutting-edge and promising strategy for inhibiting tumor progression or enhancing antitumor immunity. Therefore, in this study, we reviewed the mechanism by which TDEs regulate immune cells and their applications in immunotherapy.

Joost J. Oppenheim: 1934-2022

Joost J. Oppenheim was born in 1934 in Venlo, Netherlands and died at the age of 87 on May 14, 2022. Not one to retire or rest on his laurels, Joe remained a Senior Investigator and Head of the Cellular Immunology Section in the Cancer Innovation Laboratory of the National Cancer Institute until his passing. In the years between 1934 and 2022, Joe lived a life filled with peril, poverty, persistence, brilliance, discovery, recognition, family and satisfaction. With Joe's passing comes the end of an era and the loss of a Father of Cytokine Research who was an amazing investigator, colleague, mentor and friend.

Direct Modification of Extracellular Vesicles and Its Applications for Cancer Therapy: A Mini-Review

Extracellular vesicles (EVs) are a class of lipid membrane-bound vesicles released by various cells and mediate cell-to-cell communication. By reason of their high physiochemical stability and biocompatibility, EVs are considered as novel drug delivery system. An increasing number of studies have indicated that EVs can be modified to enhance their loading efficiency, targeting ability and therapeutic capabilities for cancer therapy. Compared with the tedious process of gene engineering approaches, direct modification of EVs is easier, faster and versatile. This mini review will summarize the prevailing approaches for direct modification of EVs. Additionally, the potential applications of modified EVs in cancer therapy are also discussed, which will help readers gain a better understanding of the technologies and applications in this field.

Universal immunotherapeutic strategy for hepatocellular carcinoma with exosome vaccines that engage adaptive and innate immune responses

Background

Personalized immunotherapy utilizing cancer vaccines tailored to the tumors of individual patients holds promise for tumors with high genetic heterogeneity, potentially enabling eradication of the tumor in its entirety.

Methods

Here, we demonstrate a general strategy for biological nanovaccines that trigger tailored tumor-specific immune responses for hepatocellular carcinoma (HCC). Dendritic cell (DC)-derived exosomes (DEX) are painted with a HCC-targeting peptide (P47-P), an α-fetoprotein epitope (AFP212-A2) and a functional domain of high mobility group nucleosome-binding protein 1 (N1ND-N), an immunoadjuvant for DC recruitment and activation, via an exosomal anchor peptide to form a “trigger” DEX vaccine (DEX_P&A2&N).

Results

DEX_P&A2&N specifically promoted recruitment, accumulation and activation of DCs in mice with orthotopic HCC tumor, resulting in enhanced cross-presentation of tumor neoantigens and de novo T cell response. DEX_P&A2&N elicited significant tumor retardation and tumor-specific immune responses in HCC mice with large tumor burdens. Importantly, tumor eradication was achieved in orthotopic HCC mice when antigenic AFP peptide was replaced with the full-length AFP (A) to form DEX_P&A&N. Supplementation of Fms-related tyrosine kinase 3 ligand greatly augmented the antitumor immunity of DEX_P&A&N by increasing immunological memory against tumor re-challenge in orthotopic HCC mice. Depletion of T cells, cross-presenting DCs and other innate immune cells abrogated the functionality of DEX_P&A&N.

Conclusions

These findings demonstrate the capacity of universal DEX vaccines to induce tumor-specific immune responses by triggering an immune response tailored to the tumors of each individual, thus presenting a generalizable approach for personalized immunotherapy of HCC, by extension of other tumors, without the need to identify tumor antigens.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-022-01266-8.

Neutrophil Functional Heterogeneity and Implications for Viral Infections and Treatments

Evidence suggests that neutrophils exert specialized effector functions during infection and inflammation, and that these cells can affect the duration, severity, and outcome of the infection. These functions are related to variations in phenotypes that have implications in immunoregulation during viral infections. Although the complexity of the heterogeneity of neutrophils is still in the process of being uncovered, evidence indicates that they display phenotypes and functions that can assist in viral clearance or augment and amplify the immunopathology of viruses. Therefore, deciphering and understanding neutrophil subsets and their polarization in viral infections is of importance. In this review, the different phenotypes of neutrophils and the roles they play in viral infections are discussed. We also examine the possible ways to target neutrophil subsets during viral infections as potential anti-viral treatments.

The mechanism of HMGB1 secretion and release

High mobility group box 1 (HMGB1) is a nonhistone nuclear protein that has multiple functions according to its subcellular location. In the nucleus, HMGB1 is a DNA chaperone that maintains the structure and function of chromosomes. In the cytoplasm, HMGB1 can promote autophagy by binding to BECN1 protein. After its active secretion or passive release, extracellular HMGB1 usually acts as a damage-associated molecular pattern (DAMP) molecule, regulating inflammation and immune responses through different receptors or direct uptake. The secretion and release of HMGB1 is fine-tuned by a variety of factors, including its posttranslational modification (e.g., acetylation, ADP-ribosylation, phosphorylation, and methylation) and the molecular machinery of cell death (e.g., apoptosis, pyroptosis, necroptosis, alkaliptosis, and ferroptosis). In this minireview, we introduce the basic structure and function of HMGB1 and focus on the regulatory mechanism of HMGB1 secretion and release. Understanding these topics may help us develop new HMGB1-targeted drugs for various conditions, especially inflammatory diseases and tissue damage.

A nuclear protein that gets released after cell death or is actively secreted by immune cells offers a promising therapeutic target for treating diseases linked to excessive inflammation. Daolin Tang from the University of Texas Southwestern Medical Center in Dallas, USA, and colleagues review how cellular stresses can trigger the accumulation of HMGB1, a type of alarm signal protein that promotes the recruitment and activation of inflammation-promoting immune cells. The researchers discuss various mechanisms that drive both passive and active release of HMGB1 into the space around cells. These processes, which include enzymatic modifications of the HMGB1 protein, cell–cell interactions and molecular pathways of cell death, could be targeted by drugs to lessen tissue damage and inflammatory disease caused by HMGB1-induced immune responses

Alpha synuclein, the culprit in Parkinson disease, is required for normal immune function

Alpha-synuclein (αS) is causally involved in the development of Parkinson disease (PD); however, its role in normal vertebrate physiology has remained unknown. Recent studies demonstrate that αS is induced by noroviral infection in the enteric nervous system of children and protects mice against lethal neurotropic viral infection. Additionally, αS is a potent chemotactic activator of phagocytes. In this report, using both wild-type and αS knockout mice, we show that αS is a critical mediator of inflammatory and immune responses. αS is required for the development of a normal inflammatory response to bacterial peptidoglycan introduced into the peritoneal cavity as well as antigen-specific and T cell responses following intraperitoneal immunization. Furthermore, we show that neural cells are the sources of αS required for immune competence. Our report supports the hypothesis that αS accumulates within the nervous system of PD individuals because of an inflammatory/immune response.

Exogenous HMGB1 Promotes the Proliferation and Metastasis of Pancreatic Cancer Cells

Background: Exogenous HMGB1 plays a vital role in tumor recurrence, and HMGB1 is ubiquitous in the tumor microenvironment. However, the mechanism of action is still unclear. We investigated the role of exogenous HMGB1 in tumor proliferation and metastasis using human SW1990 and PANC-1 cells after radiotherapy and explored the possible molecular mechanism.

Materials and Methods: Residual PANC-1 cells and SW1990 cells were isolated after radiotherapy. The supernatant after radiotherapy was collected. The relative expression of HMGB1 was evaluated by Enzyme Linked Immunosorbent Assay (ELISA). Electron microscope (EMS) was used to collect the images of pancreatic cancer cells pre and post radiotherapy treatment. The proliferation of pancreatic cancer cells which were treated with different radiation doses was measured by Carboxy Fluorescein Succinimidyl Ester (CFSE). The migration rates of pancreatic cancer cells were measured by wound healing assays. Subsequently, the expression of related proteins was detected by Western Blot. In vivo, the subcutaneous pancreatic tumor models of nude mice were established, and therapeutic capabilities were tested.

Results: HMGB1 was detected in the supernatant of pancreatic cancer cells after radiotherapy. The results of CFSE showed that exogenous HMGB1 promotes the proliferation and metastasis of pancreatic cancer cells. The western blot results showed activation of p-GSK 3β and up-regulation of N-CA, Bcl-2, and Ki67 in response to HMGB1 stimulation, while E-CA expression was down-regulated in pancreatic cancer cells in response to HMGB1 stimulation. In vivo, ethyl pyruvate (EP, HMGB1 inhibitor) inhibits the growth of tumors and HMGB1 promotes the proliferation of tumors after radiation.

Conclusion: Radiotherapy induces HMGB1 release into the extracellular space. Exogenous HMGB1 promotes the proliferation and metastasis of PANC-1 cells and SW1990 cells by activation of p-GSK 3β which is mediated by Wnt pathway.

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.

The Role of Epithelial Damage in the Pulmonary Immune Response

Pulmonary epithelial cells are widely considered to be the first line of defence in the lung and are responsible for coordinating the innate immune response to injury and subsequent repair. Consequently, epithelial cells communicate with multiple cell types including immune cells and fibroblasts to promote acute inflammation and normal wound healing in response to damage. However, aberrant epithelial cell death and damage are hallmarks of pulmonary disease, with necrotic cell death and cellular senescence contributing to disease pathogenesis in numerous respiratory diseases such as idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD) and coronavirus disease (COVID)-19. In this review, we summarise the literature that demonstrates that epithelial damage plays a pivotal role in the dysregulation of the immune response leading to tissue destruction and abnormal remodelling in several chronic diseases. Specifically, we highlight the role of epithelial-derived damage-associated molecular patterns (DAMPs) and senescence in shaping the immune response and assess their contribution to inflammatory and fibrotic signalling pathways in the lung.

Camostat mesilate inhibits pro-inflammatory cytokine secretion and improves cell viability by regulating MFGE8 and HMGN1 in lipopolysaccharide-stimulated DF-1 chicken embryo fibroblasts

Camostat mesilate (CM) possesses potential anti-viral and anti-inflammatory activities. However, it remains unknown whether CM is involved in lipopolysaccharide (LPS)-mediated inflammatory responses and cell injury. In this project, differentially expressed proteins (DEPs, fold change ≥ 1.2 or ≤ 0.83 and Q value ≤ 0.05) in response to LPS stimulation alone or in combination with CM were identified through tandem mass tags (TMT)/mass spectrometry (MS)-based proteomics analysis in DF-1 chicken embryo fibroblasts. The mRNA expression levels of filtered genes were determined by RT-qPCR assay. The results showed that CM alleviated the detrimental effect of LPS on cell viability and inhibited LPS-induced TNF-α and IL-6 secretions in DF-1 chicken embryo fibroblasts. A total of 141 DEPs that might be involved in mediating functions of both LPS and CM were identified by proteomics analysis in DF-1 chicken embryo fibroblasts. LPS inhibited milk fat globule EGF and factor V/VIII domain containing (MFGE8) expression and induced high mobility group nucleosome binding domain 1 (HMGN1) expression, while these effects were abrogated by CM in DF-1 chicken embryo fibroblasts. MFGE8 knockdown facilitated TNF-α and IL-6 secretions , reduced cell viability, stimulated cell apoptosis in DF-1 chicken embryo fibroblasts co-treated with LPS and CM. HMGN1 loss did not influence TNF-α and IL-6 secretions, cell viability, and cell apoptosis in DF-1 chicken embryo fibroblasts co-treated with LPS and CM. In conclusion, CM exerted anti-inflammatory and pro-survival activities by regulating MFGE8 in LPS-stimulated DF-1 chicken embryo fibroblasts, deepening our understanding of the roles and molecular basis of CM in protecting against Gram-negative bacteria.

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.

Exosome-Based Vaccines: History, Current State, and Clinical Trials

Extracellular vesicles (EVs) are released by most cell types as part of an intracellular communication system in crucial processes such as inflammation, cell proliferation, and immune response. However, EVs have also been implicated in the pathogenesis of several diseases, such as cancer and numerous infectious diseases. An important feature of EVs is their ability to deliver a wide range of molecules to nearby targets or over long distances, which allows the mediation of different biological functions. This delivery mechanism can be utilized for the development of therapeutic strategies, such as vaccination. Here, we have highlighted several studies from a historical perspective, with respect to current investigations on EV-based vaccines. For example, vaccines based on exosomes derived from dendritic cells proved to be simpler in terms of management and cost-effectiveness than dendritic cell vaccines. Recent evidence suggests that EVs derived from cancer cells can be leveraged for therapeutics to induce strong anti-tumor immune responses. Moreover, EV-based vaccines have shown exciting and promising results against different types of infectious diseases. We have also summarized the results obtained from completed clinical trials conducted on the usage of exosome-based vaccines in the treatment of cancer, and more recently, coronavirus disease.

Cell-derived biomimetic nanocarriers for targeted cancer therapy: cell membranes and extracellular vesicles

Nanotechnology provides synthetic carriers for cancer drug delivery that protect cargos from degradation, control drug release and increase local accumulation at tumors. However, these non-natural vehicles display poor tumor targeting and potential toxicity and are eliminated by the immune system. Recently, biomimetic nanocarriers have been widely developed based on the concept of ‘mimicking nature.’ Among them, cell-derived biomimetic vehicles have become the focus of bionics research because of their multiple natural functions, such as low immunogenicity, long circulation time and targeting ability. Cell membrane-coated carriers and extracellular vesicles are two widely used cell-based biomimetic materials. Here, this review summarizes the latest progress in the application of these two biomimetic carriers in targeted cancer therapy. Their properties and performance are compared, and their future challenges and development prospects are discussed.

In Situ Vaccination as a Strategy to Modulate the Immune Microenvironment of Hepatocellular Carcinoma

Hepatocellular Carcinoma (HCC) is a highly prevalent malignancy that develops in patients with chronic liver diseases and dysregulated systemic and hepatic immunity. The tumor microenvironment (TME) contains tumor-associated macrophages (TAM), cancer-associated fibroblasts (CAF), regulatory T cells (Treg) and myeloid-derived suppressor cells (MDSC) and is central to mediating immune evasion and resistance to therapy. The interplay between these cells types often leads to insufficient antigen presentation, preventing effective anti-tumor immune responses. In situ vaccines harness the tumor as the source of antigens and implement sequential immunomodulation to generate systemic and lasting antitumor immunity. Thus, in situ vaccines hold the promise to induce a switch from an immunosuppressive environment where HCC cells evade antigen presentation and suppress T cell responses towards an immunostimulatory environment enriched for activated cytotoxic cells. Pivotal steps of in situ vaccination include the induction of immunogenic cell death of tumor cells, a recruitment of antigen-presenting cells with a focus on dendritic cells, their loading and maturation and a subsequent cross-priming of CD8+ T cells to ensure cytotoxic activity against tumor cells. Several in situ vaccine approaches have been suggested, with vaccine regimens including oncolytic viruses, Flt3L, GM-CSF and TLR agonists. Moreover, combinations with checkpoint inhibitors have been suggested in HCC and other tumor entities. This review will give an overview of various in situ vaccine strategies for HCC, highlighting the potentials and pitfalls of in situ vaccines to treat liver cancer.

Site-specific modification and segmental isotope labelling of HMGN1 reveals long-range conformational perturbations caused by posttranslational modifications

Interactions between histones, which package DNA in eukaryotes, and nuclear proteins such as the high mobility group nucleosome-binding protein HMGN1 are important for regulating access to DNA. HMGN1 is a highly charged and intrinsically disordered protein (IDP) that is modified at several sites by posttranslational modifications (PTMs) - acetylation, phosphorylation and ADP-ribosylation. These PTMs are thought to affect cellular localisation of HMGN1 and its ability to bind nucleosomes; however, little is known about how these PTMs regulate the structure and function of HMGN1 at a molecular level. Here, we combine the chemical biology tools of protein semi-synthesis and site-specific modification to generate a series of unique HMGN1 variants bearing precise PTMs at their N- or C-termini with segmental isotope labelling for NMR spectroscopy. With access to these precisely-defined variants, we show that PTMs in both the N- and C-termini cause changes in the chemical shifts and conformational populations in regions distant from the PTM sites; up to 50-60 residues upstream of the PTM site. The PTMs investigated had only minor effects on binding of HMGN1 to nucleosome core particles, suggesting that they have other regulatory roles. This study demonstrates the power of combining protein semi-synthesis for introduction of site-specific PTMs with segmental isotope labelling for structural biology, allowing us to understand the role of PTMs with atomic precision, from both structural and functional perspectives.

Structural Characterization of the Interaction between the αMI-Domain of the Integrin Mac-1 (αMβ2) and the Cytokine Pleiotrophin

Integrin Mac-1 (α_Mβ₂) is an adhesion receptor vital to many functions of myeloid leukocytes. It is also the most promiscuous member of the integrin family capable of recognizing a broad range of ligands. In particular, its ligand-binding α_MI-domain is known to bind cationic proteins/peptides depleted in acidic residues. This contradicts the canonical ligand-binding mechanism of αI-domains, which requires an acidic amino acid in the ligand to coordinate the divalent cation within the metal ion-dependent adhesion site (MIDAS) of αI-domains. The lack of acidic amino acids in the α_MI-domain-binding sequences suggests the existence of an as-yet uncharacterized interaction mechanism. In the present study, we analyzed interactions of the α_MI-domain with a representative Mac-1 ligand, the cationic cytokine pleiotrophin (PTN). Through NMR chemical shift perturbation analysis, cross saturation, NOESY, and mutagenesis studies, we found the interaction between the α_MI-domain and PTN is divalent cation-independent and mediated mostly by hydrophobic contacts between the N-terminal domain of PTN and residues in the α5-β5 loop of α_MI-domain. The observation that increased ionic strength weakens the interaction between the proteins indicates electrostatic forces may also play a significant role in the binding. On the basis of the results from these experiments, we formulated a model of the interaction between the α_MI-domain and PTN.

An update on endotoxin neutralization strategies in Gram-negative bacterial infections

INTRODUCTION

Gram-negative bacterial infections represent still a severe problem of human health care, regarding the increase in multi-resistance against classical antibiotics and the lack of newly developed antimicrobials. For the fight against these germs, anti-infective agents must overcome and/or bind to the Gram-negative outer membrane consisting of a lipopolysaccharide (LPS, endotoxin) outer leaflet and an inner leaflet from phospholipids, with additional peripheral or integral membrane proteins (OMP's).

AREAS COVERED

The current article reviews data of existing therapeutic options and summarizes newer approaches for targeting and neutralizing endotoxins, ranging from in vitro over in vivo animal data to clinical applications by using databases such as Medline.

EXPERT OPINION

Conventional antibiotic treatment of the bacteria leads to their killing, but not necessary LPS neutralization, which may be a severe problem in particular for the systemic pathway. This is the reason why there is an increasing number of therapeutic approaches, which - besides combating whole bacteria - at the same time try to neutralize endotoxin within or outside the bacterial cells mainly responsible for the high inflammation induction in Gram-negative species.

Immunogenicity and Toxicity of Different Adjuvants Can Be Characterized by Profiling Lung Biomarker Genes After Nasal Immunization

The efficacy of vaccine adjuvants depends on their ability to appropriately enhance the immunogenicity of vaccine antigens, which is often insufficient in non-adjuvanted vaccines. Genomic analyses of immune responses elicited by vaccine adjuvants provide information that is critical for the rational design of adjuvant vaccination strategies. In this study, biomarker genes from the genomic analyses of lungs after priming were used to predict the efficacy and toxicity of vaccine adjuvants. Based on the results, it was verified whether the efficacy and toxicity of the tested adjuvants could be predicted based on the biomarker gene profiles after priming. Various commercially available adjuvants were assessed by combining them with the split influenza vaccine and were subsequently administered in mice through nasal inoculation. The expression levels of lung biomarker genes within 24 h after priming were analyzed. Furthermore, we analyzed the antibody titer, cytotoxic T lymphocyte (CTL) induction, IgG1/IgG2a ratio, leukopenic toxicity, and cytotoxicity in mice vaccinated at similar doses. The association between the phenotypes and the changes in the expression levels of biomarker genes were analyzed. The ability of the adjuvants to induce the production of antigen-specific IgA could be assessed based on the levels of Timp1 expression. Furthermore, the expression of this gene partially correlated with the levels of other damage-associated molecular patterns in bronchoalveolar lavage fluid. Additionally, the changes in the expression of proteasome- and transporter-related genes involved in major histocompatibility complex class 1 antigen presentation could be monitored to effectively assess the expansion of CTL by adjuvants. The monitoring of certain genes is necessary for the assessment of leukopenic toxicity and cytotoxicity of the tested adjuvant. These results indicate that the efficacy and toxicity of various adjuvants can be characterized by profiling lung biomarker genes after the first instance of immunization. This approach could make a significant contribution to the development of optimal selection and exploratory screening strategies for novel adjuvants.

Necroptosis in Hepatosteatotic Ischaemia-Reperfusion Injury

While liver transplantation remains the sole treatment option for patients with end-stage liver disease, there are numerous limitations to liver transplantation including the scarcity of donor livers and a rise in livers that are unsuitable to transplant such as those with excess steatosis. Fatty livers are susceptible to ischaemia-reperfusion (IR) injury during transplantation and IR injury results in primary graft non-function, graft failure and mortality. Recent studies have described new cell death pathways which differ from the traditional apoptotic pathway. Necroptosis, a regulated form of cell death, has been associated with hepatic IR injury. Receptor-interacting protein kinase 3 (RIPK3) and mixed-lineage kinase domain-like pseudokinase (MLKL) are thought to be instrumental in the execution of necroptosis. The study of hepatic necroptosis and potential therapeutic approaches to attenuate IR injury will be a key factor in improving our knowledge regarding liver transplantation with fatty donor livers. In this review, we focus on the effect of hepatic steatosis during liver transplantation as well as molecular mechanisms of necroptosis and its involvement during liver IR injury. We also discuss the immune responses triggered during necroptosis and examine the utility of necroptosis inhibitors as potential therapeutic approaches to alleviate IR injury.

NLRP6 Plays an Important Role in Early Hepatic Immunopathology Caused by Schistosoma mansoni Infection

Schistosomiasis is a debilitating parasitic disease that affects more than 200 million people worldwide and causes approximately 280,000 deaths per year. Inside the definitive host, eggs released by Schistosoma mansoni lodge in the intestine and especially in the liver where they induce a granulomatous inflammatory process, which can lead to fibrosis. The molecular mechanisms initiating or promoting hepatic granuloma formation remain poorly understood. Inflammasome activation has been described as an important pathway to induce pathology mediated by NLRP3 receptor. Recently, other components of the inflammasome pathway, such as NLRP6, have been related to liver diseases and fibrotic processes. Nevertheless, the contribution of these components in schistosomiasis-associated pathology is still unknown. In the present study, using dendritic cells, we demonstrated that NLRP6 sensor is important for IL-1β production and caspase-1 activation in response to soluble egg antigens (SEA). Furthermore, the lack of NLRP6 has been shown to significantly reduce periovular inflammation, collagen deposition in hepatic granulomas and mRNA levels of α-SMA and IL-13. Livers of Nlrp6^–/– mice showed reduced levels of CXCL1/KC, CCL2, CCL3, IL-5, and IL-10 as well as Myeloperoxidase (MPO) and Eosinophilic Peroxidase (EPO) enzymatic activity. Consistently, the frequency of macrophage and neutrophil populations were lower in the liver of NLRP6 knockout mice, after 6 weeks of infection. Finally, it was further demonstrated that the onset of hepatic granuloma and collagen deposition were also compromised in Caspase-1^–/–, IL-1R^–/– and Gsdmd^–/– mice. Our findings suggest that the NLRP6 inflammasome is an important component for schistosomiasis-associated pathology.

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 (DC_TEX-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). DC_TEX-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.

The use of tumour exosome-activated dendritic cell (DC) immunotherapy shows promise for the treatment of large established tumours. Here, the authors generate alarmin HMGN1-attached tumour exosomes which significantly improve therapy efficacy by boosting DC activation in several preclinical mouse models.

Cellular Interplay as a Consequence of Inflammatory Signals Leading to Liver Fibrosis Development

Inflammation has been known to be an important driver of fibrogenesis in the liver and onset of hepatic fibrosis. It starts off as a process meant to protect the liver from further damage, but it can become the main promoter of liver fibrosis. There are many inflammation-related pathways activated during liver fibrosis that lead to hepatic stellate cells (HSCs) activation and collagen-deposition in the liver. Such events are mostly modulated upstream of HSCs and involve signals from hepatocytes and innate immune cells. One particular event is represented by cell death during liver injury that generates multiple inflammatory signals that further trigger sterile inflammation and enhancement of inflammatory response. The assembly of inflammasome that responds to danger-associated molecular patterns (DAMPs) stimulates the release of pro-inflammatory cytokines and at the same time, initiates programmed cell death called pyroptosis. This review focuses on cellular and molecular mechanisms responsible for initiation and progress of inflammation in the liver.

Biological Functions of HMGN Chromosomal Proteins

Chromatin plays a key role in regulating gene expression programs necessary for the orderly progress of development and for preventing changes in cell identity that can lead to disease. The high mobility group N (HMGN) is a family of nucleosome binding proteins that preferentially binds to chromatin regulatory sites including enhancers and promoters. HMGN proteins are ubiquitously expressed in all vertebrate cells potentially affecting chromatin function and epigenetic regulation in multiple cell types. Here, we review studies aimed at elucidating the biological function of HMGN proteins, focusing on their possible role in vertebrate development and the etiology of disease. The data indicate that changes in HMGN levels lead to cell type-specific phenotypes, suggesting that HMGN optimize epigenetic processes necessary for maintaining cell identity and for proper execution of specific cellular functions. This manuscript contains tables that can be used as a comprehensive resource for all the English written manuscripts describing research aimed at elucidating the biological function of the HMGN protein family.

Intrinsic cancer vaccination

Immunotherapy is revolutionizing the treatment of cancer, and the current immunotherapeutics have remarkably improved the outcomes for some cancer patients. However, we still need answers for patients with immunologically cold tumors that do not benefit from the current immunotherapy treatments. Here, we suggest a novel strategy that is based on using a very old and sophisticated system for cancer immunotherapy, namely "intrinsic cancer vaccination", which seeks to awaken our own immune system to activate tumor-specific T cells. To do this, we must take advantage of the genetic instability of cancer cells and the expression of cancer cell neoantigens to trigger immunity against cancer cells. It will be necessary to not only enhance the phagocytosis of cancer cells by antigen presenting cells but also induce immunogenic cancer cell death and the subsequent immunogenic clearance, cross-priming and generation of tumor-specific T cells. This strategy will allow us to avoid using known tumor-specific antigens, ex vivo manipulation or adoptive cell therapy; rather, we will efficiently present cancer cell neoantigens to our immune system and propagate the cancer-immunity cycle. This strategy simply follows the natural cycle of cancer-immunity from its very first step, and therefore could be combined with any other treatment modality to yield enhanced efficacy.

Combining Rapid Data Independent Acquisition and CRISPR Gene Deletion for Studying Potential Protein Functions: A Case of HMGN1

CRISPR-Cas gene editing holds substantial promise in many biomedical disciplines and basic research. Due to the important functional implications of non-histone chromosomal protein HMG-14 (HMGN1) in regulating chromatin structure and tumor immunity, gene knockout of HMGN1 is performed by CRISPR in cancer cells and the following proteomic regulation events are studied. In particular, DIA mass spectrometry (DIA-MS) is utilized, and more than 6200 proteins (protein- FDR 1%) and more than 82 000 peptide precursors are reproducibly measured in the single MS shots of 2 h. HMGN1 protein deletion is confidently verified by DIA-MS in all of the clone- and dish- replicates following CRISPR. Statistical analysis reveals 147 proteins change their expressions significantly after HMGN1 knockout. Functional annotation and enrichment analysis indicate the deletion of HMGN1 induces histone inactivation, various stress pathways, remodeling of extracellular proteomes, cell proliferation, as well as immune regulation processes such as complement and coagulation cascade and interferon alpha/ gamma response in cancer cells. These results shed new lights on the cellular functions of HMGN1. It is suggested that DIA-MS can be reliably used as a rapid, robust, and cost-effective proteomic-screening tool to assess the outcome of the CRISPR experiments.

High-Mobility Group Nucleosome-Binding Protein 1 Mediates Renal Fibrosis Correlating with Macrophages Accumulation and Epithelial-to-Mesenchymal Transition in Diabetic Nephropathy Mice Model

Background/Aim: Renal fibrosis is essential for the progression of diabetic nephropathy (DN). Macrophages accumulate in diabetic kidneys and are involved in epithelial-to-mesenchymal transition (EMT), a vital mechanism leading to renal fibrosis. Recently, high-mobility group nucleosome-binding protein 1(HMGN1) was documented in promoting the recruitment and activation of antigen-presenting cells. In this study, we first reported its roles in renal fibrosis and the underlying mechanism associated with macrophage filtration and EMT. Methods: Twenty C57BL/6J mice were administered streptozotocin (STZ) to induce diabetes for 6 weeks and then divided into 4 groups: normal control group; DN group; benazepril-treated group, and insulin-treated group. Blood glucose, creatinine, and albumin in urine, hematoxylin and eosin, and Sirius red staining of kidney tissues were used to assess the renal pathology. ELISA, immunochemistry, and in situ hybridization were performed to determine the expression of HMGN1, CD68, F4/80, α-smooth muscle actin, and E-cadherin. Results: The renal expression levels of HMGN1, macrophage markers, and EMT makers were increased in DN group, and insulin treatment could reduce the overexpression of these indicators with a better effect than benazepril treatment. Both treatments could not obviously ameliorate urine albumin-to-creatinine ratio, collagen expression, and renal histological changes in STZ-induced diabetic mice. Correlation analysis indicated that there was a relationship among HMGN1, macrophage markers, EMT markers, and collagen expression in DN mice. Conclusion: HMGN1 may promote macrophages accumulation and EMT, suggesting a potential therapeutic target for preventing renal fibrosis development in DN.

Alarmin augments the antitumor immunity of lentiviral vaccine in ectopic, orthotopic and autochthonous hepatocellular carcinoma mice

It is a daunting therapeutic challenge to completely eradicate hepatocellular carcinoma (HCC) from patients. Alpha-fetoprotein (AFP) -based vaccines appear promising, however the efficacy needs to be improved. Methods: Here, we explore if fusing high-mobility group nucleosome binding protein 1 (HMGN1), a potent immunoadjuvant, to AFP (lenti-HA) can augment the antitumor immunity of AFP-expressing lentiviral vector (lenti-AFP), a vehicle extensively employed for genetic immunization with high transduction efficacy and good safety profiles. The antitumor immunity of Lenti-HA was systemically assessed in ectopic, orthotopic and autochthonous HCC models. Results: Lenti-HA elicited strong anti-HCC effects in mice and amplified the antitumor immunity of lenti-AFP by reducing effective dose 6-fold. Importantly, lenti-HA induced a robust antitumor immune response with prolonged survival rate and improved the immune and tumor microenvironment in mice with carcinogen-induced autochthonous HCC. Lenti-HA localized primarily to lymphoid organs with no preference for specific immune cell types. Activated dendritic cells (DCs), particularly CD103+CD11b- DCs, were also actively recruited to lymph nodes in lenti-HA-treated HCC mice. Moreover, lenti-HA-transduced human DCs elicited stronger immune response than lenti-AFP against HCC cells in vitro. Conclusion: Our study demonstrates that HMGN1 augments the antitumor immunity of AFP-expressing lentiviral vaccines in HCC mice and human cells in vitro and thus provides a new therapeutic strategy for HCC.

Dendritic Cell-Mediated Th2 Immunity and Immune Disorders

Dendritic cells (DCs) are the professional antigen-presenting cells that recognize and present antigens to naïve T cells to induce antigen-specific adaptive immunity. Among the T-cell subsets, T helper type 2 (Th2) cells produce the humoral immune responses required for protection against helminthic disease by activating B cells. DCs induce a Th2 immune response at a certain immune environment. Basophil, eosinophil, mast cells, and type 2 innate lymphoid cells also induce Th2 immunity. However, in the case of DCs, controversy remains regarding which subsets of DCs induce Th2 immunity, which genes in DCs are directly or indirectly involved in inducing Th2 immunity, and the detailed mechanisms underlying induction, regulation, or maintenance of the DC-mediated Th2 immunity against allergic environments and parasite infection. A recent study has shown that a genetic defect in DCs causes an enhanced Th2 immunity leading to severe atopic dermatitis. We summarize the Th2 immune-inducing DC subsets, the genetic and environmental factors involved in DC-mediated Th2 immunity, and current therapeutic approaches for Th2-mediated immune disorders. This review is to provide an improved understanding of DC-mediated Th2 immunity and Th1/Th2 immune balancing, leading to control over their adverse consequences.

Combined treatment with HMGN1 and anti-CD4 depleting antibody reverses T cell exhaustion and exerts robust anti-tumor effects in mice

BACKGROUND

Transient depletion of CD4⁺ T cells results in tumor suppression and survival benefit in murine models; however, the tumor progression and recurrence still occur over more long-term monitoring of mice. Thus, we explored an additional strategy to enhance endogenous immune responses by an alarmin, high mobility group nucleosome binding protein 1 (HMGN1).

METHODS

The anti-tumor effects of HMGN1, anti-CD4 depleting antibody, and their combined treatment were monitored in the Colon26 or the B16F10 subcutaneous murine models. The tumor-infiltrating CD8⁺ T cell proliferation, differentiation, exhaustion, and its gene expression were determined by flow cytometry, transcriptome analysis, and quantitative real-time PCR.

RESULTS

Our results show that a systemic administration of low doses of HMGN1 with an anti-CD4 depleting antibody (HMGN1/αCD4) promoted expansion of CD8⁺ T cell populations (e.g. CD137⁺ PD-1⁺ and CD44^hi PD-1⁺), recruited CCR7⁺ migratory dendritic cells to the tumor, and reduced co-inhibitory molecules (e.g. PD-1, LAG-3, and TIM-3) to counteract CD8⁺ T cell exhaustion.

CONCLUSION

The HMGN1/αCD4 treatment expanded effector CD8⁺ T cells and prolonged their anti-tumor activities by rescuing them from exhaustion, thus resulting in tumor regression and even rejection in long-term monitored mice.

HMGN1 and R848 Synergistically Activate Dendritic Cells Using Multiple Signaling Pathways

High mobility group nucleosome-binding protein 1 (HMGN1 or N1) is a Th1-polarizing alarmin, but alone is insufficient to induce antitumor immunity. We previously showed that combination of N1 and R848, a synthetic TLR7/8 agonist, synergistically activates dendritic cells (DCs) and induces therapeutic antitumor immunity, however, it remained unclear how N1 and R848 synergistically activate DCs. Here, we show that co-stimulation with N1 and R848 of human monocyte-derived DCs (MoDCs) markedly upregulated DC's surface expression of CD80, CD83, CD86, and HLA-DR, as well as synergistic production of pro-inflammatory cytokines including IL-12p70, IL-1β, and TNF-α. This combination also synergistically activated NF-κB and multiple MAPKs that are involved in DC maturation. Moreover, N1 and R848 synergistically increased nuclear translocation of interferon (IFN) regulatory transcription factors (e.g., IRF3 and IRF7) and promoted the expression of type 1 IFNs such as IFN-α2, IFN-α4, and IFN-β1. Similar signaling pathways were also induced in mouse bone marrow-derived DCs (BMDCs). RNA-seq analysis in human MoDCs revealed that N1 plus R848 synergistically upregulated the expression of genes predominantly involved in DC maturation pathway, particularly genes critical for the polarization of Th1 immune responses (e.g., IL12A, IL12B, and IFNB1, etc.). Overall, our findings show that (1) N1 synergizes with R848 in activating human and mouse DCs and (2) the synergistic effect based on various intracellular signaling events culminated in the activation of multiple transcriptional factors. These findings have important implications for future clinical trials since N1 and R848 synergistically promoted optimal Th1 lineage immune responses resulting in tumor rejection in mice.