ALK+ALCLs induce cutaneous, HMGB-1-dependent IL-8/CXCL8 production by keratinocytes through NF-κB activation

The Recruitment and Immune Suppression Mechanisms of Myeloid-Derived Suppressor Cells and Their Impact on Bone Metastatic Cancer

BACKGROUND

MDSCs are immature neutrophils and monocytes with immunosuppressive potentials, involving mononuclear MDSCs (M-MDSCs) and polymorphonuclear MDSCs (PMN-MDSCs).

RECENT FINDINGS

They are significant components of the tumor microenvironment (TME). Besides, recent studies also verified that MDSCs also facilitated the progression of bone metastasis by regulating the network of cytokines and the function of immune cells.

CONCLUSION

It is necessary to summarize the mechanisms of MDSC recruitment and immunosuppression, and their impact on bone metastasis.

Multifaceted role of HMGB1: From nuclear functions to cytoplasmic and extracellular signaling in inflammation and cancer-Review

High-mobility group box 1 (HMGB1) is a highly conserved nuclear protein involved in key nuclear processes such as DNA repair, replication, and gene regulation. Beyond its established nuclear roles, HMGB1 has crucial functions in the cytoplasm and extracellular environment. When translocated to the cytoplasm, HMGB1 plays a role in autophagy, cell survival, and immune response modulation. In its extracellular form, HMGB1 acts as a damage-associated molecular pattern molecule, initiating inflammatory responses by interacting with receptors such as Receptor for advanced glycation endproducts and Toll-like receptors. Recent studies have shown its role in promoting tissue regeneration, wound healing, and angiogenesis, highlighting its dual role in both inflammation and tissue repair. Notably, the redox status of HMGB1 influences its function, with the reduced form promoting autophagy and the disulfide form driving inflammation. Dysregulation of HMGB1 contributes to the progression of various diseases, including cancer, where it influences tumor growth, metastasis, and resistance to therapy. This review provides an overview of the nuclear, cytoplasmic, and extracellular roles of HMGB1, discussing its involvement in nuclear homeostasis, rare genetic diseases, autophagy, inflammation, cancer progression, and tissue regeneration.

MiR-146a-5p enrichment in small-extracellular vesicles of relapsed pediatric ALCL patients promotes macrophages infiltration and differentiation

Anaplastic large cell lymphoma (ALCL) is a CD30-positive lymphoma accounting for 20% of all pediatric T-cell lymphomas. Current first line treatment can cure most of ALCL patients but 10-30% of them are resistant or relapse. In this context, liquid biopsy has the potential to help clinicians in disease screening and treatment response monitoring. Small-RNA-sequencing analysis performed on plasma small-extracellular vesicles (s-EVs) from 20 pediatric anaplastic lymphoma kinase positive (ALK + ) ALCL patients at diagnosis revealed a specific miRNAs cargo in relapsed patients compared to non-relapsed, with seven miRNAs enriched in s-EVs of relapsed patients. MiR-146a-5p and miR-378a-3p showed a negative prognostic impact both in univariate and multivariate analysis, possibly representing, together with let-7 g-5p, a miRNA panel for the early identification of high-risk patients. Among them, miR-146a-5p is known to modulate tumor supporting-M2 macrophages differentiation, but the role of these cells in pediatric ALK + ALCL is still unknown. To elucidate the role of miR-146a-5p and M2 macrophages in pediatric ALCL disease, THP-1-derived macrophages were treated with s-EVs from ALK + ALCL cell lines, showing increased miR-146a-5p intracellular expression, migrating capability and M2-markers CD163 and Arginase-1 upregulation. In turn, conditioned media from M2 macrophages or miR-146a-5p-transfected THP-1 increased ALCL cells' aggressive features and were enriched in interleukin-8. Overall, these data suggest a role of miR-146a-5p in promoting macrophage infiltration and M2-like polarization in ALCL. Our findings incite further investigation on the role of M2 macrophages in ALCL aggressiveness and dissemination, also considering the novel treatment options targeting tumor associated macrophages.

ALK+ Anaplastic Large Cell Lymphoma (ALCL)-Derived Exosomes Carry ALK Signaling Proteins and Interact with Tumor Microenvironment

Simple Summary

ALK+ anaplastic large cell lymphoma (ALK+ ALCL) is a distinct type of aggressive non-Hodgkin lymphoma of T-cell origin, which is characterized by overexpression and activation of ALK kinase due to chromosomal translocations of the gene. The most frequent chromosomal aberration is the t(2;5) resulting in the NPM-ALK chimeric protein, which exerts its oncogenic functions through activation of multiple oncogenic pathways. Exosomes, the best characterized type of extracellular vesicles, are secreted from the tumor cells, thus transferring signals to other cells that uptake exosomes. In this study, we demonstrate that ALK+ ALCL cells secrete exosomes that carry critical molecules of ALK signaling, which can be taken up by other cells with significant biologic effects including functional interactions with tumor microenvironment cells, which may contribute to tumor aggressiveness and possibly resistance to treatment.

Abstract

The oncogenic pathways activated by the NPM-ALK chimeric kinase of ALK+ anaplastic large cell lymphoma (ALCL) are well characterized; however, the potential interactions of ALK signaling with the microenvironment are not yet known. Here we report that ALK+ ALCL-derived exosomes contain critical components of ALK signaling as well as CD30, and that exosome uptake by lymphoid cells led to increased proliferation and expression of critical antiapoptotic proteins by the recipient cells. The bone marrow fibroblasts highly uptake ALK+ ALCL-derived exosomes and acquire a cancer-associated fibroblast (CAF) phenotype. Moreover, exosome-mediated activation of stromal cells altered the cytokine profile of the microenvironment. These interactions may contribute to tumor aggressiveness and possibly resistance to treatment.

Mast Cells and Skin and Breast Cancers: A Complicated and Microenvironment-Dependent Role

Mast cells are important sentinel cells in host defense against infection and major effector cells in allergic disease. The role of these cells in cancer settings has been widely debated. The diverse range of mast cell functions in both immunity and tissue remodeling events, such as angiogenesis, provides multiple opportunities for mast cells to modify the tumor microenvironment. In this review, we consider both skin and breast cancer settings to address the controversy surrounding the importance of mast cells in the host response to tumors. We specifically address the key mediators produced by mast cells which impact tumor development. The role of environmental challenges in modifying mast cell responses and opportunities to modify mast cell responses to enhance anti-tumor immunity are also considered. While the mast cell's role in many cancer contexts is complicated and poorly understood, the activities of these tissue resident and radioresistant cells can provide important opportunities to enhance anti-cancer responses and limit cancer development.

Premetastasis

Sterile inflammation within primary tumor tissues can spread to distant organs that are devoid of tumor cells. This happens in a manner dependent on tumor-led secretome, before the actual metastasis occurs. The premetastatic microenvironment is established in this way and is at least partly regulated by hijacking the host innate immune system. The biological manifestation of premetastasis include increased vascular permeability, cell mobilization via the blood stream, degradation of the extracellular matrix, immunosuppression, and host antineoplastic activities.

CircCFL1/MiR-107 Axis Targeting HMGB1 Promotes the Malignant Progression of Diffuse Large B-Cell Lymphoma Tumors

Objective

The pathogenesis of diffuse large B-cell lymphoma (DLBCL) has not yet been fully elucidated. An increasing number of studies have shown that circular RNAs (circRNAs) play an important role in tumorigenesis and development. The aim of this study was to investigate the effect of CircCFL1 on the malignant progression of DLBCL.

Methods

RT-qPCR was used to detect the expression levels of CircCFL1 and miR-107. A dual-luciferase reporter gene experiment was conducted to verify that CircCFL1 targeted miR-107 and the miR-107 target gene HMGB1. BrdU, transwell, and MTT tests were performed to detect cell invasion and proliferation. Western blot analysis was used to detect the phosphorylation of proteins. Xenograft models were established to confirm the effect of CircCFL1 on DLBCL tumor growth in vivo.

Results

The expression of CircCFL1 in cells transfected with the CircCFL1 overexpression vector was higher than that in the control group. After overexpressing CircCFL1, the expression of miR-107 in cells decreased significantly, and the protein level of HMGB1 increased. The dual-luciferase reporter gene experiment showed that CircCFL1 directly bound to miR-107 and reduced the inhibition of the target gene HMGB1. After CircCFL1 was overexpressed, cell migration and proliferation were enhanced. The tumor volume and weight in the lentivirus CircCFL1 group were higher than those in the lentivirus NC group.

Conclusion

Results showed that the circRNA CircCFL1 could regulate the expression of HMGB1 through miR-107 to promote the proliferation and migration of DLBCL.

High mobility group box 1 (HMGB1): a pivotal regulator of hematopoietic malignancies

High mobility group box 1 (HMGB1) is a nonhistone chromatin-associated protein that has been widely reported to play a pivotal role in the pathogenesis of hematopoietic malignancies. As a representative damage-associated molecular pattern (DAMP), HMGB1 normally exists inside cells but can be secreted into the extracellular environment through passive or active release. Extracellular HMGB1 binds with several different receptors and interactors to mediate the proliferation, differentiation, mobilization, and senescence of hematopoietic stem cells (HSCs). HMGB1 is also involved in the formation of the inflammatory bone marrow (BM) microenvironment by activating proinflammatory signaling pathways. Moreover, HMGB1-dependent autophagy induces chemotherapy resistance in leukemia and multiple myeloma. In this review, we systematically summarize the emerging roles of HMGB1 in carcinogenesis, progression, prognosis, and potential clinical applications in different hematopoietic malignancies. In summary, targeting the regulation of HMGB1 activity in HSCs and the BM microenvironment is highly beneficial in the diagnosis and treatment of various hematopoietic malignancies.

Oxidative Stress-Induced HMGB1 Release from Melanocytes: A Paracrine Mechanism Underlying the Cutaneous Inflammation in Vitiligo

Vitiligo is a cutaneous depigmentation disorder caused by the destruction of epidermal melanocytes. The generation and the skin infiltration of autoreactive CD8⁺ cytotoxic T cells triggered by oxidative stress play a critical role in vitiligo. High-mobility group protein B1 (HMGB1) is a classic damage-associated molecular pattern molecule with strong proinflammatory effects in inflammatory reactions. A previous study reported an enhanced expression of HMGB1 in vitiligo lesions, but the role of HMGB1 in cutaneous inflammation of vitiligo is still unknown. In the present study, we initially found that HMGB1 was released from the nucleus of melanocytes in vitiligo perilesional skin. Furthermore, cultured normal human melanocytes could release HMGB1 under treatment with hydrogen peroxide. Moreover, HMGB1 facilitated the secretion of CXCL16 and IL-8 from keratinocytes by binding to the receptor for advanced glycation end products and activating NF-κB and extracellular signal-regulated kinase signaling pathways. Subsequently, HMGB1 led to the formation of chemotaxis for the migration of CD8⁺ T cells from patients with vitiligo by increasing the release of CXCL16 from keratinocytes. Additionally, HMGB1 promoted the maturation of dendritic cells from patients with vitiligo. Altogether, our study demonstrates that HMGB1 released from melanocytes contributes to the formation of oxidative stress-induced autoimmunity in vitiligo.

Plumbagin ameliorates hepatic ischemia-reperfusion injury in rats: Role of high mobility group box 1 in inflammation, oxidative stress and apoptosis

Ischemia-reperfusion (I/R) injury is a pathological process which magnifies with the ensuing inflammatory response and endures with the increase of oxidants especially during reperfusion. The present study was conducted to assess the possible modulatory effects of plumbagin, the active constituent extracted from the roots of traditional medicinal plant Plumbago zeylanica L., on the dire role of high mobility group box 1 (HMGB1) as well as the associated inflammation, oxidative stress and apoptotic cell death following hepatic I/R. Four groups of rats were included: sham-operated, sham-operated treated with plumbagin, I/R (30 min ischemia and 1 h reperfusion) and I/R treated with plumbagin. Pretreatment with plumbagin markedly improved hepatic function and structural integrity compared to the I/R group, as manifested by depressed plasma transaminases and lactate dehydrogenase (LDH) activities as well as alleviated tissue pathological lesions. Plumbagin prominently hampered HMGB1 expression and subsequently quelled inflammatory cascades, as nuclear factor κB (NF-κB), tumor necrosis factor-alpha (TNF-α) and myeloperoxidase (MPO) activity. It also interrupted reactive oxygen species (ROS)-HMGB1loop as evident by restored liver reduced glutathione (GSH), elevated glutathione peroxidase (GPx) activity, along with decreased liver lipid peroxidation. Simultaneously, plumbagin significantly ameliorated apoptosis by amending the mRNA expressions of both anti-apoptotic (Bcl-2) and pro-apoptotic (Bax). The present results revealed that plumbagin is endowed with hepatoprotective activity ascribed to its antioxidant, anti-inflammatory and anti-apoptotic properties which are partially mediated through dampening of HMGB1 expression.

Interleukin 8 activity influences the efficacy of adenoviral oncolytic immunotherapy in cancer patients

After the landmark approval of T-VEC, oncolytic viruses are finding their way to the clinics. However, response rates have still room for improvement, and unfortunately there are currently no available markers to predict responses for oncolytic immunotherapy. Interleukin 8 (IL-8) production is upregulated in many cancers and it also connects to several pathways that have been shown to impair the efficacy of adenoviral immunotherapy. We studied the role of IL-8 in 103 cancer patients treated with oncolytic adenoviruses. We found high baseline serum IL-8 concentration to be independently associated with poor prognosis (p<0.001). Further, normal baseline IL-8 was associated with improved prognostic potential of calculation of the neutrophil-to-lymphocyte ratio (p<0.001). Interestingly, a decrease in IL-8 concentration after treatment with oncolytic adenovirus predicted better overall survival (p<0.001) and higher response rate, although this difference was not significant (p=0.066). We studied the combination of adenovirus and IL-8 neutralizing antibody ex vivo in single cell suspensions and in co-cultures of tumor-associated CD15+ neutrophils and CD3+ tumor-infiltrating lymphocytes derived from fresh patient tumor samples. These results indicate a role for IL-8 as a biomarker in oncolytic virotherapy, but additionally provide a rationale for targeting IL-8 to improve treatment efficacy. In conclusion, curtailing the activity of IL-8 systemically or locally in the tumor microenvironment could improve anti-tumor immune responses resulting in enhanced efficacy of adenoviral immunotherapy of cancer.

Crosstalk between microRNA and DNA Methylation Offers Potential Biomarkers and Targeted Therapies in ALK-Positive Lymphomas

The discovery of microRNA (miRNA) has provided new and powerful tools for studying the mechanism, diagnosis and treatment of human cancers. The down-regulation of tumor suppressive miRNA by hypermethylation of CpG island (CpG is shorthand for 5′-C-phosphate-G-3′, that is, cytosine and guanine separated by only one phosphate) is emerging as a common hallmark of cancer and appears to be involved in drug resistance. This review discusses the role of miRNA and DNA methylation in drug resistance mechanisms and highlights their potential as anti-cancer therapies in Anaplastic Lymphoma Kinase (ALK)-positive lymphomas. These are a sub-type of non-Hodgkin’s lymphomas that predominantly affect children and young adults and are characterized by the expression of the nucleophosmin (NPM)/ALK chimeric oncoprotein. Dysregulation of miRNA expression and regulation has been shown to affect several signaling pathways in ALK carcinogenesis and control tumor growth, both in cell lines and mouse models. These data suggest that the modulation of DNA methylation and/or the expression of these miRNA could serve as new biomarkers and have potential therapeutic applications for ALK-positive malignancies.

Protective effect of glycyrrhizin on myocardial ischemia/reperfusion injury-induced oxidative stress, inducible nitric oxide synthase and inflammatory reactions through high-mobility group box 1 and mitogen-activated protein kinase expression

Glycyrrhizin, which is a type of perennial leguminous caudex, has been used in various Asian countries, including P.R. China, India and Japan, for thousands of years. The present study was designed to investigate the protective effect of glycyrrhizin on myocardial ischemia/reperfusion (I/R) injury through oxidative stress, inducible nitric oxide synthase (iNOS), and inflammatory reactions via high-mobility group box 1 (HMGB1) and mitogen-activated protein kinase (MAPK) expression. Sprague-Dawley rats were divided into five groups: Sham; myocardial I/R injury + non-treated; myocardial I/R injury + 2 mg/kg glycyrrhizin; myocardial I/R injury + 4 mg/kg glycyrrhizin; and myocardial I/R injury + 10 mg/kg glycyrrhizin. Pre-treatment with glycyrrhizin significantly reduced infarct size and inhibited creatine kinase, creatine kinase-MB, lactate dehydrogenase and cardiac troponin T activities in rats with myocardial I/R injury. Furthermore, glycyrrhizin treatment significantly suppressed oxidative stress, iNOS protein expression and inflammatory reactions in rats with myocardial I/R injury. Additionally, treatment with glycyrrhizin significantly decreased the release of HMGB1 from the cerebral cortex into the serum in rats with myocardial I/R injury. Notably, glycyrrhizin significantly suppressed p-ERK, p-p38 MAPK and p-c-Jun N-terminal kinase protein expressions, and promoted extracellular signal-regulated kinase protein expression in rats with myocardial I/R injury. Collectively, the present study indicates that the protective effect of glycyrrhizin may reduce myocardial I/R injury through oxidative stress, iNOS and inflammatory reactions, via HMGB1 and MAPK expression.

Prediction of drug-induced liver injury using keratinocytes

Drug-induced liver injury (DILI) is one of the most common adverse drug reactions. DILI is often accompanied by skin reactions, including rash and pruritus. However, it is still unknown whether DILI-associated genes such as S100 calcium-binding protein A and interleukin (IL)-1β are involved in drug-induced skin toxicity. In the present study, most of the tested hepatotoxic drugs such as pioglitazone and diclofenac induced DILI-associated genes in human and mouse keratinocytes. Keratinocytes of mice at higher risk for DILI exhibited an increased IL-1β basal expression. They also showed a higher inducibility of IL-1β when treated by pioglitazone. Mice at higher risk for DILI showed even higher sums of DILI-associated gene basal expression levels and induction rates in keratinocytes. Our data suggest that DILI-associated genes might be involved in the onset and progression of drug-induced skin toxicity. Furthermore, we might be able to identify individuals at higher risk of developing DILI less invasively by examining gene expression patterns in keratinocytes. Copyright © 2017 John Wiley & Sons, Ltd.

Proinflammatory effect of high-mobility group protein B1 on keratinocytes: an autocrine mechanism underlying psoriasis development

Psoriasis is an autoimmune skin disease, in which keratinocytes play a crucial pathogenic role. High-mobility group protein B1 (HMGB1) is an inflammatory factor that can be released from keratinocyte nuclei in psoriatic lesions. We aimed to investigate the proinflammatory effect of HMGB1 on keratinocytes and the contribution of HMGB1 to psoriasis development. Normal human keratinocytes were treated with recombinant human HMGB1, and the production of inflammatory factors and the intermediary signalling pathways were examined. Furthermore, the imiquimod-induced psoriasis-like mouse model was used to investigate the role of HMGB1 in psoriasis development in vivo. A total of 11 inflammatory factors were shown to be upregulated by HMGB1 in keratinocytes, among which interleukin (IL)-18 showed the greatest change. We then found that activation of the nuclear factor-κB signalling pathway and inflammasomes accounted for HMGB1-induced IL-18 expression and secretion. Moreover, HMGB1 and downstream IL-18 contributed to the development of psoriasiform dermatitis in the imiquimod-treated mice. In addition, T-helper 17 immune response in the psoriasis-like mouse model could be inhibited by both HMGB1 and IL-18 blockade. Our findings indicate that HMGB1 secreted from keratinocytes can facilitate the production and secretion of inflammatory factors such as IL-18 in keratinocytes in an autocrine way, thus promoting the development of psoriasis. Blocking the proinflammatory function of the HMGB1-IL-18 axis may be useful for psoriasis treatment in the future. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

PHF11 expression and cellular distribution is regulated by the Toll-Like Receptor 3 Ligand Polyinosinic:Polycytidylic Acid in HaCaT keratinocytes

Background

Inflammatory skin diseases such as atopic dermatitis and psoriasis represent a complex interaction between the skin and infiltrating immune cells, resulting in damage to the skin barrier and increased inflammation. Polymorphisms in PHF11 have been associated with dermatitis and allergy and PHF11 regulates the transcription of T-cell cytokines as well as class switching to IgE in activated B-cells. The importance of skin barrier homeostasis in the context of inflammatory skin diseases, together with reports identifying PHF11 as an interferon-induced gene, have led us to examine its role in the innate immune response of keratinocytes.

Results

We developed a cell culture model that allowed us to analyze the effects of the double-stranded RNA analogue poly(I:C) on a confluent cell monolayer immediately after a 24-h treatment, as well as three days after withdrawal of treatment. Immediately after treatment with poly(I:C), PHF11, IL8, and interferon-dependent ISG15 RNA expression was increased. This was accompanied by nuclear localization of PHF11 as well the tight junction protein claudin-1. Knock-down of PHF11 resulted in increased interleukin-8 expression and secretion immediately following treatment with poly(I:C), as well as changes in the cellular distribution of membrane-bound and increased nuclear claudin-1 that was observed up to 3 days after the withdrawal of poly(I:C). This was associated with lower cell density and a decrease in the number of cells in the G1 phase of the cell cycle.

Conclusions

In addition to a role for PHF11 in lymphocyte gene expression, we have now shown that PHF11 was part of the keratinocyte innate immune response by poly(I:C). As knock-down of PHF11 was associated with increased expression of the pro-inflammatory chemokine IL-8 and changes in the cellular distribution of claudin-1, a change normally associated with increased proliferation and migration, we suggest that PHF11 may contribute to epidermal recovery following infection or other damage.

Combined targeting of high-mobility group box-1 and interleukin-8 to control micrometastasis potential in gastric cancer

Micrometastasis is the major cause of treatment failure in gastric cancer (GC). Because epithelial-to-mesenchymal transition (EMT) is considered to develop prior to macroscopic metastasis, EMT-promoting factors may affect micrometastasis. This study aimed to evaluate the role of extracellular high-mobility group box-1 (HMGB1) in EMT and the treatment effect of combined targeting of HMGB1 and interleukin-8 (IL-8) at early-stage GC progression through interrupting EMT promotion. Extracellular HMGB1 was induced by human recombinant HMGB1 and pCMV-SPORT6-HMGB1 plasmid transfection. EMT activation was evaluated by immunoblotting, immunofluorescence and immunohistochemistry. Increased migration/invasion activities were evaluated by in vitro transwell migration/invasion assay using all histological types of human GC cell lines (N87, MKN28 SNU-1 and KATOIII), N87-xenograft BALB/c nude mice and human paired serum-tissue GC samples. HMGB1-induced soluble factors were measured by chemiluminescent immunoassay. Inhibition effects of tumor growth and EMT activation by combined targeting of HMGB1 and IL-8 were evaluated in N87-xenograft nude mice. Serum HMGB1 increases along the GC carcinogenesis and reaches maximum before macroscopic metastasis. Overexpressed extracellular HMGB1 promoted EMT activation and increased cell motility/invasiveness through ligation to receptor for advanced glycation end products. HMGB1-induced IL-8 overexpression contributed the HMGB1-induced EMT in GC in vitro and in vivo. Blocking HMGB1 caused significant reduction of tumor growth, and addition of human recombinant IL-8 rescues this antitumor effects. Our results imply the role of HMGB1 in EMT through IL-8 mediation, and a potential mechanism of GC micrometastasis. Our observations suggest combination strategy of HMGB1 and IL-8 as a promising diagnostic and therapeutic target to control GC micrometastasis.

IL-9 induces IL-8 production via STIM1 activation and ERK phosphorylation in epidermal keratinocytes: A plausible mechanism of IL-9R in atopic dermatitis

BACKGROUND

IL-9 and its receptor play important roles in the pathogenesis of asthma. Its role in atopic dermatitis (AD) was examined in just a few studies, including nucleotide polymorphisms, increased transcriptional levels of IL-9 and IL-9R in diseased skin, and an association of blood IL-9 levels with clinical severity.

OBJECTIVE

Little was known about the pathophysiological regulation of IL-9/IL-9R in AD skin. We asked whether IL-9R was expressed in epidermal keratinocytes; if so, what the functional outcome, cytokine production, and signaling pathway of IL-9/IL-9R in keratinocytes are.

METHODS

We measured and compared the expression of IL-9R in skin from AD patients and controls by immunofluorescence. We also performed in vitro studies on the IL-9-treated primary keratinocytes, including flow cytometry for IL-9R expressions, Western blotting for mTOR, S6K, ERK, p38, and STAT3 activations, ELISA for cytokine levels, and immunofluorescence for STIM1.

RESULTS

We found that IL-9R was indeed expressed in keratinocytes but not in fibroblasts. Its expression in keratinocytes was enhanced by IL-4 but not by TGF-beta1. IL-9 induced a moderate production of IL-8 but not CXCL16, CCL22, TSLP, nor IL-33. IL-9 induced formation of STIM1-puncta. IL-9 induced ERK phosphorylation both dose- and time-dependently, but not mTOR, S6K, p38, or STAT3. Pretreatment with U0126 (ERK inhibitor) but not rapamycin (mTOR inhibitor) abrogated the IL-9-mediated IL-8 production. Blockage of STIM1 with BTP2 or SKF96265 abrogated ERK phosphorylation and IL-8 production induced by IL-9.

CONCLUSION

This study represents the first to show the regulation of the IL-9-STIM1-ERK-IL-8 axis in keratinocyte, and how the axis might play an important role in the pathophysiology of AD.

HMGB1 in health and disease

Complex genetic and physiological variations as well as environmental factors that drive emergence of chromosomal instability, development of unscheduled cell death, skewed differentiation, and altered metabolism are central to the pathogenesis of human diseases and disorders. Understanding the molecular bases for these processes is important for the development of new diagnostic biomarkers, and for identifying new therapeutic targets. In 1973, a group of non-histone nuclear proteins with high electrophoretic mobility was discovered and termed high-mobility group (HMG) proteins. The HMG proteins include three superfamilies termed HMGB, HMGN, and HMGA. High-mobility group box 1 (HMGB1), the most abundant and well-studied HMG protein, senses and coordinates the cellular stress response and plays a critical role not only inside of the cell as a DNA chaperone, chromosome guardian, autophagy sustainer, and protector from apoptotic cell death, but also outside the cell as the prototypic damage associated molecular pattern molecule (DAMP). This DAMP, in conjunction with other factors, thus has cytokine, chemokine, and growth factor activity, orchestrating the inflammatory and immune response. All of these characteristics make HMGB1 a critical molecular target in multiple human diseases including infectious diseases, ischemia, immune disorders, neurodegenerative diseases, metabolic disorders, and cancer. Indeed, a number of emergent strategies have been used to inhibit HMGB1 expression, release, and activity in vitro and in vivo. These include antibodies, peptide inhibitors, RNAi, anti-coagulants, endogenous hormones, various chemical compounds, HMGB1-receptor and signaling pathway inhibition, artificial DNAs, physical strategies including vagus nerve stimulation and other surgical approaches. Future work further investigating the details of HMGB1 localization, structure, post-translational modification, and identification of additional partners will undoubtedly uncover additional secrets regarding HMGB1's multiple functions.

Molecular signaling of the HMGB1/RAGE axis contributes to cholesteatoma pathogenesis

Abstract

Cholesteatoma represents progressive expansion of the keratinizing squamous epithelium in the middle ear with subsequent chronic inflammation in subepithelial connective tissues. The hypothesis was tested that receptor for advanced glycation endproduct (RAGE) and its ligand, high-mobility box 1 (HMGB1), are overexpressed in cholesteatoma, and the RAGE/HMGB1 axis might contribute to its pathogenesis. Cholesteatoma samples (n = 36) and 27 normal skin specimens were studied by immunohistochemistry (IHC) for HMGB1 and RAGE expression. Effects of HMGB1 signaling on proliferation, migration, cytokine production, and apoptosis of human immortalized keratinocytes (HaCaTs) and normal keratinocytes were studied by quantitative reverse transcription (qRT)-PCR, IHC, Western blots, and flow cytometry after cell co-incubation with HMGB1. While all studied tissues expressed HMGB1, its expression was higher in cholesteatoma than in normal skin (p < 0.0001). All cases of cholesteatoma also showed elevated RAGE expression levels, and only 7/27 (26 %) of normal skin specimens were weakly positive for RAGE. Proliferation and migration of HaCaT cells incubated with HMGB1 were up-regulated (p < 0.05). HMGB1 also prevented HaCaT cell apoptosis and induced activation of several molecular signaling pathways in keratinocytes. The data suggest that in cholesteatoma, HMGB1 released from stressed or necrotic epithelial cells and binding to RAGE overexpressed in keratinocytes initiates molecular signaling that culminates in pro-inflammatory cytokine release and chronic inflammation.

Key message

HMGB1 signaling engages multiple activation pathways in RAGE-positive keratinocytes.

HMGB1 protects RAGE-positive keratinocytes from drug-induced apoptosis.

Keratinocyte proliferation is controlled via RAGE and HMGB1 molecular signaling.

Molecular signaling of the HMGB1/RAGE axis contributes to cholesteatoma pathogenesis.

Electronic supplementary material

The online version of this article (doi:10.1007/s00109-014-1217-3) contains supplementary material, which is available to authorized users.

Porphyromonas gingivalis promotes invasion of oral squamous cell carcinoma through induction of proMMP9 and its activation

Recent epidemiological studies have revealed a significant association between periodontitis and oral squamous cell carcinoma (OSCC). Furthermore, matrix metalloproteinase 9 (MMP9) is implicated in the invasion and metastasis of tumour cells. We examined the involvement of Porphyromonas gingivalis, a periodontal pathogen, in OSCC invasion through induced expression of proMMP and its activation. proMMP9 was continuously secreted from carcinoma SAS cells, while P. gingivalis infection increased proenzyme expression and subsequently processed it to active MMP9 in culture supernatant, which enhanced cellular invasion. In contrast, Fusobacterium nucleatum, another periodontal organism, failed to demonstrate such activities. The effects of P. gingivalis were observed with highly invasive cells, but not with the low invasivetype. P. gingivalis also stimulated proteinase-activated receptor 2 (PAR2) and enhanced proMMP9 expression, which promoted cellular invasion. P. gingivalis mutants deficient in gingipain proteases failed to activate MMP9. Infected SAS cells exhibited activation of ERK1/2, p38, and NF-kB, and their inhibitors diminished both proMMP9-overexpression and cellular invasion. Together, our results show that P. gingivalis activates the ERK1/2-Ets1, p38/HSP27, and PAR2/NF-kB pathways to induce proMMP9 expression, after which the proenzyme is activated by gingipains to promote cellular invasion of OSCC cell lines. These findings suggest a novel mechanism of progression and metastasis of OSCC associated with periodontitis.

The activation of HMGB1 as a progression factor on inflammation response in normal human bronchial epithelial cells through RAGE/JNK/NF-κB pathway

Extracellular high-mobility group box-1 (HMGB-1) has been implicated in the inflammation response leading to the precancerous lesions of non-small cell lung cancer (NSCLC). However, the role of HMGB-1 in the inflammation response in normal human bronchial epithelial (NHBE) cells and its underlying mechanisms were still not fully understood. In this study, the inflammation response in NHBE cells was stimulated by 2.5, 5, and 10 μg/ml HMGB-1. However, the receptor for advanced glycation end products (RAGE) blocker RAGE-Ab (5 μg/ml) or 10 μM c-Jun N-terminal kinases (JNK) inhibitor SP600125 could inhibit HMGB1-induced the release of inflammation cytokines including TNF-α, IL-8, IL-10, and MCP-1 in a dose-dependent manner. Furthermore, HMGB1-induced RAGE protein expression, JNK and NF-κB activation were attenuated by the pretreatment with RAGE-Ab or JNK inhibitor SP600125 in Western blot analysis. Our data indicated that HMGB-1 induced inflammation response in NHBE cells through activating RAGE/JNK/NF-κB pathway. HMGB-1 could act as a therapeutic target for inflammation leading NHBE cells to the precancerous lesions of NSCLC.