Hypoxia-inducible factor mediates hypoxic and tumor necrosis factor alpha-induced increases in tumor necrosis factor-alpha converting enzyme/ADAM17 expression by synovial cells

How We Interpret Thrombosis with Thrombocytopenia Syndrome?

Platelets play an important role in hemostasis, and a low platelet count usually increases the risk of bleeding. Conditions in which thrombosis occurs despite low platelet counts are referred to as thrombosis with thrombocytopenia syndrome, including heparin-induced thrombocytopenia, vaccine-induced immune thrombotic thrombocytopenia, paroxysmal nocturnal hemoglobinuria, antiphospholipid syndrome, thrombotic microangiopathy (TMA), and disseminated intravascular coagulation. TMA includes thrombotic thrombocytopenic purpura, Shiga toxin-producing Escherichia coli-associated hemolytic uremic syndrome (HUS), and atypical HUS. Patients with these pathologies present with thrombosis and consumptive thrombocytopenia associated with the activation of platelets and the coagulation system. Treatment varies from disease to disease, and many diseases have direct impacts on mortality and organ prognosis if therapeutic interventions are not promptly implemented. Underlying diseases and the results of physical examinations and general laboratory tests as part of a thorough workup for patients should promptly lead to therapeutic intervention before definitive diagnosis. For some diseases, the diagnosis and initial treatment must proceed in parallel. Utilization of not only laboratory tests but also various scoring systems is important for validating therapeutic interventions based on clinical information.

A Disintegrin and metalloproteinase carves T cell abnormalities and pathogenesis in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a complex autoimmune disorder impacting various organs, notably prevalent in women of reproductive age. This review explores the involvement of a disintegrin and metalloproteinases (ADAMs) in SLE pathogenesis. Despite advancements in understanding SLE through genome and transcriptome studies, the role of ADAMs in post-translational regulations remains insufficiently explored. ADAMs, transmembrane proteins with diverse functions, impact cell adhesion, migration, and inflammation by shedding cell surface proteins, growth factors, and receptors. Notably, ADAM9 is implicated in Th17 cell differentiation, which is crucial in SLE pathology. ADAM10 and ADAM17 play pivotal roles in T-cell biology, influencing immune cell development and differentiation. Elevated soluble ADAM substrates in SLE patients serve as potential biomarkers correlating with disease activity. Targeting ADAMs or their substrates offers promising therapeutic avenues for SLE management and treatment enhancement.

Efferocytosis: Current status and future prospects in the treatment of autoimmune diseases

Billions of apoptotic cells are swiftly removed from the human body daily. This clearance process is regulated by efferocytosis, an active anti-inflammatory process during which phagocytes engulf and remove apoptotic cells. However, impaired clearance of apoptotic cells is associated with the development of various autoimmune diseases, such as rheumatoid arthritis, systemic lupus erythematosus, and inflammatory bowel disease. In this review, we conducted a comprehensive search of relevant studies published from January 1, 2000, to the present, focusing on efferocytosis, autoimmune disease pathogenesis, regulatory mechanisms governing efferocytosis, and potential treatments targeting this process. Our review highlights the key molecules involved in different stages of efferocytosis-namely, the "find me," "eat me," and "engulf and digest" phases-while elucidating their relevance to autoimmune disease pathology. Furthermore, we explore the therapeutic potential of modulating efferocytosis to restore immune homeostasis and mitigate autoimmune responses. By providing theoretical underpinnings for the targeting of efferocytosis in the treatment of autoimmune diseases, this review contributes to the advancement of therapeutic strategies in this field.

Soluble ACE2 correlates with severe COVID-19 and can impair antibody responses

Identifying immune modulators that impact neutralizing antibody responses against severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is of great relevance. We postulated that high serum concentrations of soluble angiotensin-converting enzyme 2 (sACE2) might mask the spike and interfere with antibody maturation toward the SARS-CoV-2-receptor-binding motif (RBM). We tested 717 longitudinal samples from 295 COVID-19 patients and showed a 2- to 10-fold increase of enzymatically active sACE2 (a-sACE2), with up to 1 μg/mL total sACE2 in moderate and severe patients. Fifty percent of COVID-19 sera inhibited ACE2 activity, in contrast to 1.3% of healthy donors and 4% of non-COVID-19 pneumonia patients. A mild inverse correlation of a-sACE2 with RBM-directed serum antibodies was observed. In silico, we show that sACE2 concentrations measured in COVID-19 sera can disrupt germinal center formation and inhibit timely production of high-affinity antibodies. We suggest that sACE2 is a biomarker for COVID-19 and that soluble receptors may contribute to immune suppression informing vaccine design.

The mechanism by which cannabidiol (CBD) suppresses TNF-α secretion involves inappropriate localization of TNF-α converting enzyme (TACE)

Cannabidiol (CBD) is a phytocannabinoid derived from Cannabis sativa that exerts anti-inflammatory mechanisms. CBD is being examined for its putative effects on the neuroinflammatory disease, multiple sclerosis (MS). One of the major immune mediators that propagates MS and its mouse model experimental autoimmune encephalomyelitis (EAE) are macrophages. Macrophages can polarize into an inflammatory phenotype (M1) or an anti-inflammatory phenotype (M2a). Therefore, elucidating the impact on macrophage polarization with CBD pre-treatment is necessary to understand its anti-inflammatory mechanisms. To study this effect, murine macrophages (RAW 264.7) were pre-treated with CBD (10 µM) or vehicle (ethanol 0.1 %) and were either left untreated (naive; cell media only), or stimulated under M1 (IFN-γ + lipopolysaccharide, LPS) or M2a (IL-4) conditions for 24 hr. Cells were analyzed for macrophage polarization markers, and supernatants were analyzed for cytokines and chemokines. Immunofluorescence staining was performed on M1-polarized cells for the metalloprotease, tumor necrosis factor-α-converting enzyme (TACE), as this enzyme is responsible for the secretion of TNF-α. Overall results showed that CBD decreased several markers associated with the M1 phenotype while exhibiting less effects on the M2a phenotype. Significantly, under M1 conditions, CBD increased the percentage of intracellular and surface TNF-α but decreased secreted TNF-α. This phenomenon might be mediated by TACE as staining showed that CBD sequestered TACE intracellularly. CBD also prevented RelA nuclear translocation. These results suggest that CBD may exert its anti-inflammatory effects by reducing M1 polarization and decreasing TNF-α secretion via inappropriate localization of TACE and RelA.

Endotheliopathy of liver sinusoidal endothelial cells in liver disease

Liver is the largest solid organ in the abdominal cavity, with sinusoid occupying about half of its volume. Under liver disease, hemodynamics in the liver tissue dynamically change, resulting in injury to liver sinusoidal endothelial cells (LSECs). We discuss the injury of LSECs in liver diseases in this article. Generally, in noninflamed tissues, vascular endothelial cells maintain quiescence of circulating leukocytes, and unnecessary blood clotting is inhibited by multiple antithrombotic factors produced by the endothelial cells. In the setting of inflammation, injured endothelial cells lose these functions, defined as inflammatory endotheliopathy. In chronic hepatitis C, inflammatory endotheliopathy in LSECs contributes to platelet accumulation in the liver tissue, and the improvement of thrombocytopenia by splenectomy is attenuated in cases with severe hepatic inflammation. In COVID-19, LSEC endotheliopathy induced by interleukin (IL)-6 trans-signaling promotes neutrophil accumulation and platelet microthrombosis in the liver sinusoids, resulting in liver injury. IL-6 trans-signaling promotes the expression of intercellular adhesion molecule-1, chemokine (C-X-C motif) ligand (CXCL1), and CXCL2, which are the neutrophil chemotactic mediators, and P-selectin, E-selectin, and von Willebrand factor, which are involved in platelet adhesion to endothelial cells, in LSECs. Restoring LSECs function is important for ameliorating liver injury. Prevention of endotheliopathy is a potential therapeutic strategy in liver disease.

ADAM17 regulates the proliferation and extracellular matrix of keloid fibroblasts by mediating the EGFR/ERK signaling pathway

To investigate the role of a disintegrin and metalloprotease protein 17 (ADAM17) in regulating the proliferation and extracellular matrix (ECM) expression of keloid fibroblasts (KFs) via the epidermal growth factor receptor (EGFR)/extracellular signal-regulated kinase (ERK) pathway. ADAM17 expression in keloid tissues was detected by western blotting. KFs were isolated, cultured and divided into the control, shNC (negative control), shADAM17, transforming growth factor-β1 (TGF-β1), TGF-β1 + shNC and TGF-β1 + shADAM17 groups. The expression of ECM was detected by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). Western blotting was performed to detect the expression of proteins. Cell proliferation was detected by a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay, while cell invasion and migration were examined by Transwell and wound healing assays. The expression of ADAM17 was increased in keloid tissues and KFs. Compared with the control group, the expression of p-EGFR and p-ERK/1/2/ERK1/2, as well as the expression of collagen I, collagen III, connective tissue growth factor (CTGF) and α-smooth muscle actin (α-SMA), were decreased in KFs from the shADAM17 group, with decreased cell proliferation, invasion and migration. In contrast, the TGF-β1 group presented the opposite trend in these aspects. In addition, compared with the TGF-β1 group, KFs from the TGF-β1 + shADAM17 group had decreased ECM expression, proliferation, invasion and migration. ADAM17 expression was upregulated in keloid tissues. Silencing ADAM17 may inhibit the activity of the EGFR/ERK pathway to limit the deposition of ECM in KFs with reduced proliferation, invasion and migration.

Hypoxia and TNF-α Synergistically Induce Expression of IL-6 and IL-8 in Human Fibroblast-like Synoviocytes via Enhancing TAK1/NF-κB/HIF-1α Signaling

Hypoxia and increased levels of inflammatory cytokines in the joints are characteristics of rheumatoid arthritis (RA). However, the effects of hypoxia and tumor necrosis factor-α (TNF-α) on interleukin (IL)-6 and IL-8 production on fibroblast-like synoviocytes (FLSs) remain to be clarified. This study aimed to explore how hypoxia and TNF-α affect the expression of IL-6 and IL-8 in human FLSs isolated from RA patients. Hypoxia or TNF-α treatment alone significantly increased the expression and promoter activity of IL-6, IL-8, and hypoxia-inducible factor-1α (HIF-1α). Treatment of hypoxic FLSs with TNF-α further significantly elevated the expression of these cytokines and enhanced promoter activity of HIF-1α, which was abrogated by treatment with the HIF-1α inhibitor YC-1. Similarly, TNF-α alone elevated the phosphorylation and promoter activity of nuclear factor-κBp65 (NF-κBp65) in the FLSs. These effects were further enhanced by the combined treatment of hypoxia and TNFα but were attenuated by the NF-κB inhibitor BAY11-7082. NF-κB-p65 inhibition decreased the effect of TNF-α on HIF-1α upregulation in the FLSs in response to hypoxia. The combination of hypoxia and TNF-α also significantly upregulated transforming growth factor-β-activated kinase 1 (TAK1) expression, and silencing TAK1 dramatically decreased NF-κB-p65, HIF-1α, IL-6, and IL-8 expression under the same conditions. Our results indicate that hypoxia and TNF-α synergistically increase IL-6 and IL-8 expression in human FLSs via enhancing TAK1/NF-κB/HIF-1α signaling.

The Biochemistry and Physiology of A Disintegrin and Metalloproteinases (ADAMs and ADAM-TSs) in Human Pathologies

Metalloproteinases are a group of proteinases that plays a substantial role in extracellular matrix remodeling and its molecular signaling. Among these metalloproteinases, ADAMs (a disintegrin and metalloproteinases) and ADAM-TSs (ADAMs with thrombospondin domains) have emerged as highly efficient contributors mediating proteolytic processing of various signaling molecules. ADAMs are transmembrane metalloenzymes that facilitate the extracellular domain shedding of membrane-anchored proteins, cytokines, growth factors, ligands, and their receptors and therefore modulate their biological functions. ADAM-TSs are secretory, and soluble extracellular proteinases that mediate the cleavage of non-fibrillar extracellular matrix proteins. ADAMs and ADAM-TSs possess pro-domain, metalloproteinase, disintegrin, and cysteine-rich domains in common, but ADAM-TSs have characteristic thrombospondin motifs instead of the transmembrane domain. Most ADAMs and ADAM-TSs are activated by cleavage of pro-domain via pro-protein convertases at their N-terminus, hence directing them to various signaling pathways. In this article, we are discussing not only the structure and regulation of ADAMs and ADAM-TSs, but also the importance of these metalloproteinases in various human pathophysiological conditions like cardiovascular diseases, colorectal cancer, autoinflammatory diseases (sepsis/rheumatoid arthritis), Alzheimer's disease, proliferative retinopathies, and infectious diseases. Therefore, based on the emerging role of ADAMs and ADAM-TSs in various human pathologies, as summarized in this review, these metalloproteases can be considered as critical therapeutic targets and diagnostic biomarkers.

Prognostic Comparison between cTACE and H101-TACE in Unresectable Hepatocellular Carcinoma (HCC): A Propensity-Score Matching Analysis

Background

Transarterial chemoembolization (TACE) is the most common treatment for patients with HCC who are unsuitable for radical therapies. Conventional TACE (cTACE) takes advantage of the preferential hepatic arterial supply of HCC for the targeted delivery of chemotherapeutic agents suspended in lipiodol, followed by embolization or reduction of arterial flow using various types of particles while sparing the surrounding liver parenchyma. Aims and Objectives. The current study is aimed at comparing the efficacy and safety profiles of transarterial infusion of recombinant human type-5 adenovirus (H101-TACE) with conventional transarterial chemoembolization (cTACE) in patients with unresectable hepatocellular carcinoma (HCC).

Methods

Unresectable HCC patients that received H101-based TACE or cTACE from August 2018 to September 2021 were retrospectively evaluated. Propensity score matching (PSM) has a 1 : 1 ratio to eliminate possible confounder imbalances across cohorts. The main outcome was overall survival (OS), while secondary outcomes were progression-free survival (PFS) and tumor response.

Results

This study included 111 patients classified across two cohorts: the H101-TACE cohort (n = 37) and the cTACE cohort (n = 74). Median OS within the H101-TACE cohort was 9.0 months longer than within the cTACE cohort before PSM (22.1 vs. 13.1 months, P = 0.043) and 9.3 months longer following PSM (22.1 vs. 12.8 months, P = 0.004). The median PFS within the H101-TACE cohort was 3.2 months longer compared to the cTACE cohort before PSM (6.5 vs. 3.3 months, P = 0.046) and 2.5 months after PSM (6.5 vs. 4.0 months, P = 0.012). The disease control rate for H101 and control cohorts was 81.1% and 59.5%, accordingly (P = 0.039).

Conclusion

The present study demonstrated that the H101-TACE is safe and efficient and can considerably enhance prognostic results for unresectable HCC compared to cTACE.

Comparison of the Efficacy Among Transcatheter Arterial Chemoembolization (TACE)-Radiofrequency Ablation Plus Apatinib, TACE Plus Apatinib, and TACE Alone for Hepatocellular Carcinoma: A Retrospective Study

BACKGROUND

This study aimed to investigate the efficacy and safety of apatinib plus transarterial chemoembolization (TACE) and radiofrequency ablation (RFA) in the therapy of hepatocellular carcinoma (HCC) patients.

METHODS

From December 2015 to June 2018, 175 eligible participants were included in our research. Twenty-four patients who received apatinib plus TACE and RFA were categorized as the TACE + RFA-A group, 82 patients who received apatinib plus TACE were categorized as the TACE-A group, and 69 patients who received TACE alone were categorized as the TACE group. Treatment complications, treatment response, overall survival (OS), and time to progression (TTP) were recorded. Survival analyses were compared. Univariate and multivariate Cox analyses were conducted to investigate the predictive factors for OS and TTP. A subgroup analysis was carried out.

RESULTS

The median TTP was 8.0 months (95% CI 6.7-9.3) in the TACE + RFA-A, which was longer than the TACE-A group (6.0 months, 95% CI 4.8-7.2) and TACE group (3.0 months, 95% CI 2.3-3.7); the difference was statistically significant (P < 0.001). The median OS was 23.0 months (95% CI 12.6-33.4) in the TACE + RFA-A group, 18.0 months (95% CI 16.2-19.8) in the TACE-A group, and 8.0 months (95% CI 5.3-10.7) in the TACE group; the difference was statistically significant (P < 0.001). The objective response rate (ORR) was higher in TACE + RFA-A t group (M1, 70.8% vs 65.9% vs. 46.4%, P = 0.023; M3, 58.3% vs. 53.7% vs. 26.1%, P = 0.001). Multivariate Cox analysis demonstrated that treatment strategy and tumor size were independent prognostic factors for the OS and TTP, whereas the Child-Pugh stage was predictive factor of OS. No treatment-related death was observed. The toxicity was comparable between the two groups.

CONCLUSION

TACE combined with RFA plus apatinib is a safe three-modality treatment for the intermediate or advanced HCC, and it demonstrated better efficacy than TACE plus apatinib or TACE alone.

Elucidating the role of hypoxia-inducible factor in rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic multifactorial disease, provocative, and degenerative autoimmune condition that impacts millions of individuals around the globe. As a result of this understanding, anti-inflammatory drugs have been created, perhaps widely effective (like steroids) and highly specialized methods (including anti-TNF antibody) using biological therapies (including TNF inhibitors). Despite this, the connections between inflammatory response, articular development, and intracellular responsiveness to changes in oxygen concentration are undervalued in rheumatoid arthritis. Hypoxia, or a lack of oxygen, is thought to cause enhanced synovial angiogenesis in RA, which is mediated by some of the hypoxia-inducible factors like vascular endothelial growth factor (VEGF). Substantial genetic alterations occur when the HIF regulatory factors signaling cycle is activated, allowing organelles, tissues, and species to acclimatize to decreasing oxygen saturation. The most well-characterized hypoxia-responsive transcripts are the angiogenic stimulant VEGF, whose production is greatly elevated by hypoxia in several types of cells, especially RA synovium fibroblasts. Blocking vascular endothelial growth factors has been demonstrated to be helpful in murine models of rheumatism, indicating how hypoxia could trigger the angiogenesis process, resulting in the progression of RA. These mechanisms highlight the intimate affiliation amongst hypoxia, angiogenesis, and inflammation in rheumatoid arthritis. This review will look at how hypoxia activates molecular pathways and how other pathways involving inflammatory signals develop and sustain synovitis in rheumatoid arthritis.

Multiphysics and multiscale modeling of microthrombosis in COVID-19

Emerging clinical evidence suggests that thrombosis in the microvasculature of patients with Coronavirus disease 2019 (COVID-19) plays an essential role in dictating the disease progression. Because of the infectious nature of SARS-CoV-2, patients’ fresh blood samples are limited to access for in vitro experimental investigations. Herein, we employ a novel multiscale and multiphysics computational framework to perform predictive modeling of the pathological thrombus formation in the microvasculature using data from patients with COVID-19. This framework seamlessly integrates the key components in the process of blood clotting, including hemodynamics, transport of coagulation factors and coagulation kinetics, blood cell mechanics and adhesive dynamics, and thus allows us to quantify the contributions of many prothrombotic factors reported in the literature, such as stasis, the derangement in blood coagulation factor levels and activities, inflammatory responses of endothelial cells and leukocytes to the microthrombus formation in COVID-19. Our simulation results show that among the coagulation factors considered, antithrombin and factor V play more prominent roles in promoting thrombosis. Our simulations also suggest that recruitment of WBCs to the endothelial cells exacerbates thrombogenesis and contributes to the blockage of the blood flow. Additionally, we show that the recent identification of flowing blood cell clusters could be a result of detachment of WBCs from thrombogenic sites, which may serve as a nidus for new clot formation. These findings point to potential targets that should be further evaluated, and prioritized in the anti-thrombotic treatment of patients with COVID-19. Altogether, our computational framework provides a powerful tool for quantitative understanding of the mechanism of pathological thrombus formation and offers insights into new therapeutic approaches for treating COVID-19 associated thrombosis.

Emerging clinical evidence suggests that thrombosis in the microvasculature of patients with Coronavirus disease 2019 (COVID-19) plays an essential role in dictating the disease progression. We employ a novel multiphysics and multiscale computational framework to investigate the underlying mechanism of the pathological formation of microthrombi and circulating cell clusters in COVID-19. We quantify the contributions of many prothrombotic factors reported in the literature, such as stasis, the derangement in blood coagulation factor levels and activities, inflammatory responses of endothelial cells and leukocytes to the microthrombus formation in COVID-19, through which we identify the potential targets that should be further evaluated, and prioritized in the anti-thrombotic treatment of patients with COVID-19.

Covid-19 and Liver Injury: Role of Inflammatory Endotheliopathy, Platelet Dysfunction, and Thrombosis

Liver injury, characterized predominantly by elevated aspartate aminotransferase and alanine aminotransferase, is a common feature of coronavirus disease 2019 (COVID-19) symptoms caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2). Additionally, SARS-CoV-2 infection is associated with acute-on-chronic liver failure in patients with cirrhosis and has a notably elevated mortality in patients with alcohol-related liver disease compared to other etiologies. Direct viral infection of the liver with SARS-CoV-2 remains controversial, and alternative pathophysiologic explanations for its hepatic effects are an area of active investigation. In this review, we discuss the effects of SARS-CoV-2 and the inflammatory environment it creates on endothelial cells and platelets more generally and then with a hepatic focus. In doing this, we present vascular inflammation and thrombosis as a potential mechanism of liver injury and liver-related complications in COVID-19.

Non-classical Vitamin D Actions for Renal Protection

Chronic Kidney Disease (CKD), a disorder that affects 11% of the world's population, is characterized by an acceleration in skeletal, immune, renal, and cardiovascular aging that increases the risk of cardiovascular mortality by 10- to 20-fold, compared to that in individuals with normal renal function. For more than two decades, the progressive impairment in renal capacity to maintain normal circulating levels of the hormonal form of vitamin D (1,25-dihydroxyvitamin D or calcitriol) was considered the main contributor to the reduced survival of CKD patients. Accordingly, calcitriol administration was the treatment of choice to attenuate the progression of secondary hyperparathyroidism (SHPT) and its adverse impact on bone health and vascular calcification. The development of calcitriol analogs, designed to mitigate the resistance to calcitriol suppression of PTH associated with CKD progression, demonstrated survival benefits unrelated to the control of SHPT or skeletal health. The exhaustive search for the pathophysiology behind survival benefits associated with active vitamin D analogs has identified novel anti-inflammatory, anti-hypertensive, anti-aging actions of the vitamin D endocrine system. A major paradigm shift regarding the use of calcitriol or active vitamin D analogs to improve survival in CKD patients emerged upon demonstration of a high prevalence of vitamin D (not calcitriol) deficiency at all stages of CKD and, more significantly, that maintaining serum levels of the calcitriol precursor, 25(OH)vitamin D, above 23 ng/ml delayed CKD progression. The cause of vitamin D deficiency in CKD, however, is unclear since vitamin D bioactivation to 25(OH)D occurs mostly at the liver. Importantly, neither calcitriol nor its analogs can correct vitamin D deficiency. The goals of this chapter are to present our current understanding of the pathogenesis of vitamin D deficiency in CKD and of the causal link between defective vitamin D bioactivation to calcitriol and the onset of molecular pathways that promote CKD progression independently of the degree of SHPT. An understanding of these mechanisms will highlight the need for identification of novel sensitive biomarkers to assess the efficacy of interventions with vitamin D and/or calcitriol(analogs) to ameliorate CKD progression in a PTH-independent manner.

Transmembrane TNF and Its Receptors TNFR1 and TNFR2 in Mycobacterial Infections

Tumor necrosis factor (TNF) is one of the main cytokines regulating a pro-inflammatory environment. It has been related to several cell functions, for instance, phagocytosis, apoptosis, proliferation, mitochondrial dynamic. Moreover, during mycobacterial infections, TNF plays an essential role to maintain granuloma formation. Several effector mechanisms have been implicated according to the interactions of the two active forms, soluble TNF (solTNF) and transmembrane TNF (tmTNF), with their receptors TNFR1 and TNFR2. We review the impact of these interactions in the context of mycobacterial infections. TNF is tightly regulated by binding to receptors, however, during mycobacterial infections, upstream activation signalling pathways may be influenced by key regulatory factors either at the membrane or cytosol level. Detailing the structure and activation pathways used by TNF and its receptors, such as its interaction with solTNF/TNFRs versus tmTNF/TNFRs, may bring a better understanding of the molecular mechanisms involved in activation pathways which can be helpful for the development of new therapies aimed at being more efficient against mycobacterial infections.

Combined Radiochemotherapy: Metalloproteinases Revisited

Besides cytotoxic DNA damage irradiation of tumor cells triggers multiple intra- and intercellular signaling processes, that are part of a multilayered, treatment-induced stress response at the unicellular and tumor pathophysiological level. These processes are intertwined with intrinsic and acquired resistance mechanisms to the toxic effects of ionizing radiation and thereby co-determine the tumor response to radiotherapy. Proteolysis of structural elements and bioactive signaling moieties represents a major class of posttranslational modifications regulating intra- and intercellular communication. Plasma membrane-located and secreted metalloproteinases comprise a family of metal-, usually zinc-, dependent endopeptidases and sheddases with a broad variety of substrates including components of the extracellular matrix, cyto- and chemokines, growth and pro-angiogenic factors. Thereby, metalloproteinases play an important role in matrix remodeling and auto- and paracrine intercellular communication regulating tumor growth, angiogenesis, immune cell infiltration, tumor cell dissemination, and subsequently the response to cancer treatment. While metalloproteinases have long been identified as promising target structures for anti-cancer agents, previous pharmaceutical approaches mostly failed due to unwanted side effects related to the structural similarities among the multiple family members. Nevertheless, targeting of metalloproteinases still represents an interesting rationale alone and in combination with other treatment modalities. Here, we will give an overview on the role of metalloproteinases in the irradiated tumor microenvironment and discuss the therapeutic potential of using more specific metalloproteinase inhibitors in combination with radiotherapy.

A wake-like state in vitro induced by transmembrane TNF/soluble TNF receptor reverse signaling

Tumor necrosis factor alpha (TNF) has sleep regulatory and brain development roles. TNF promotes sleep in vivo and in vitro while TNF inhibition diminishes sleep. Transmembrane (tm) TNF and the tmTNF receptors (Rs), are cleaved by tumor necrosis factor alpha convertase to produce soluble (s) TNF and sTNFRs. Reverse signaling occurs in cells expressing tmTNF upon sTNFR binding. sTNFR administration in vivo inhibits sleep, thus we hypothesized that a wake-like state in vitro would be induced by sTNFR-tmTNF reverse signaling. Somatosensory cortical neuron/glia co-cultures derived from male and female mice lacking both TNFRs (TNFRKO), or lacking TNF (TNFKO) and wildtype (WT) mice were plated onto six-well multi-electrode arrays. Daily one-hour electrophysiological recordings were taken on culture days 4 through 14. sTNFR1 (0.0, 0.3, 3, 30, 60, and 120 ng/µL) was administered on day 14. A final one-hour recording was taken on day 15. Four measures were characterized that are also used to define sleep in vivo: action potentials (APs), burstiness index (BI), synchronization of electrical activity (SYN), and slow wave power (SWP; 0.25-3.75 Hz). Development rates of these emergent electrophysiological properties increased in cells from mice lacking TNF or both TNFRs compared to cells from WT mice. Decreased SWP, after the three lowest doses (0.3, 3 and 30 ng/µL) of the sTNFR1, indicate a wake-like state in cells from TNFRKO mice. A wake-like state was also induced after 3 ng/µl sTNFR1 treatment in cells from TNFKO mice, which express the TNFR1 ligand, lymphotoxin alpha. Cells from WT mice showed no treatment effects. Results are consistent with prior studies demonstrating involvement of TNF in brain development, TNF reverse signaling, and sleep regulation in vivo. Further, the current demonstration of sTNFR1 induction of a wake-like state in vitro is consistent with the idea that small neuronal/glial circuits manifest sleep- and wake-like states analogous to those occurring in vivo. Finally, that sTNF forward signaling enhances sleep while sTNFR1 reverse signaling enhances a wake-like state is consistent with other sTNF/tmTNF/sTNFR1 brain actions having opposing activities.

Loss of the tumor suppressor BTG3 drives a pro-angiogenic tumor microenvironment through HIF-1 activation

B-cell translocation gene 3 (BTG3) is a member of the antiproliferative BTG gene family and is a downstream target of p53. Here, we show that senescence triggered by BTG3 depletion was accompanied by a secretome enriched with cytokines, growth factors, and matrix-remodeling enzymes, which could promote angiogenesis and cell scattering in vitro. We present evidence that at least part of these activities can be explained by elevated HIF-1α activity. Mechanistically, the BTG3 C-terminal domain competes with the coactivator p300 for binding the HIF-1α transactivation domain. The angiogenic promoting effect of BTG3 knockdown was largely diminished upon co-depletion of HIF-1α, indicating that HIF-1α is a major downstream target of BTG3 in the control of angiogenesis. In vivo, ectopic expression of BTG3 suppresses angiogenesis in xenograft tumors; and syngenic tumor growth and metastasis were enhanced in Btg3-null mice. Moreover, analysis of clinical datasets revealed that a higher BTG3/VEGFA expression ratio correlates with improved patient survival in a number of cancer types. Taken together, our findings highlight the non-autonomous regulation of tumor microenvironment by BTG3 while suppressing tumor progression.

Current and novel therapeutic targets in the treatment of rheumatoid arthritis

Rheumatoid arthritis (RA), a multifactorial disease characterized by synovitis, cartilage destruction, bone erosion, and periarticular decalcification, finally results in impairment of joint function. Both genetic and environmental factors are risk factors in the development of RA. Unwanted side effects accompany most of the current treatment strategies, and around 20-40% of patients with RA do not clinically benefit from these treatments. The unmet need for new treatment options for RA has prompted research in the development of novel agents acting through physiologically and pharmacologically relevant targets. Here we discuss in detail three critical pathways, Janus kinase/signal transducer and activator of transcription (JAK/STAT), Th17, and hypoxia-inducible factor (HIF), and their roles as unique therapeutic targets in the field of RA. Some of the less developed but potential targets like nucleotide-binding and oligomerization domain-like receptor containing protein 3 (NLRP3) inflammasome and histone deacetylase 1 (HDAC1) are also discussed.

Selective Increment of Synovial Soluble TYRO3 Correlates with Disease Severity and Joint Inflammation in Patients with Rheumatoid Arthritis

Objective

To investigate the role of TAM receptors in rheumatoid arthritis (RA) by determining synovial tissue TAM receptor expression, synovial fluid levels of soluble TAM receptors, and the relationship between soluble TAM receptors, joint inflammation and disease activity.

Methods

TAM receptor expression was determined by immunohistochemistry on the synovium from RA and osteoarthritis (OA) patients. Soluble (s) Tyro3, sAxl, sMer, and their ligand Gas6 were measured by ELISA in the synovial fluid of RA (n = 28) and OA (n = 12) patients and cytokine levels by multiplex immunoassay in RA samples. Correlation analyses were performed among sTAM receptors with local cytokine levels; systemic disease parameters like erythrocyte sedimentation rate (ESR), rheumatoid factor (RF), and anticyclic citrullinated peptide antibodies (ACPA); and disease activity scores (DAS28-ESR) in RA patients.

Results

TAM receptors were expressed on different locations in the synovial tissue (lining, sublining, and blood vessels), and a similar expression pattern was observed in RA and OA patients. Synovial fluid sTyro3 and sMer were significantly enhanced in RA compared to OA patients, whereas no significant differences in sAxl and Gas6 levels were found. In RA samples, sTyro3 levels, but not sMer, correlated positively with proinflammatory local cytokines and the systemic factor erythrocyte sedimentation rate. Moreover, stratification analysis showed high sTyro3 levels positively correlated with higher DAS28-ESR and in RF and ACPA double positive RA patients.

Conclusion

sTyro3 in the synovial fluid of RA patients correlates with local inflammatory molecules and systemic disease activity. These findings suggest that the reduced negative control of cell activation by TAM receptors due to their shedding in the synovial fluid, mainly sTyro3, favoring joint inflammation in RA patients.

Barley-ß-glucans reduce systemic inflammation, renal injury and aortic calcification through ADAM17 and neutral-sphingomyelinase2 inhibition

In chronic kidney disease (CKD), hyperphosphatemia-induced inflammation aggravates vascular calcification (VC) by increasing vascular smooth muscle cell (VSMC) osteogenic differentiation, ADAM17-induced renal and vascular injury, and TNFα-induction of neutral-sphingomyelinase2 (nSMase2) to release pro-calcifying exosomes. This study examined anti-inflammatory β-glucans efficacy at attenuating systemic inflammation in health, and renal and vascular injury favoring VC in hyperphosphatemic CKD. In healthy adults, dietary barley β-glucans (Bβglucans) reduced leukocyte superoxide production, inflammatory ADAM17, TNFα, nSMase2, and pro-aging/pro-inflammatory STING (Stimulator of interferon genes) gene expression without decreasing circulating inflammatory cytokines, except for γ-interferon. In hyperphosphatemic rat CKD, dietary Bβglucans reduced renal and aortic ADAM17-driven inflammation attenuating CKD-progression (higher GFR and lower serum creatinine, proteinuria, kidney inflammatory infiltration and nSMase2), and TNFα-driven increases in aortic nSMase2 and calcium deposition without improving mineral homeostasis. In VSMC, Bβglucans prevented LPS- or uremic serum-induced rapid increases in ADAM17, TNFα and nSMase2, and reduced the 13-fold higher calcium deposition induced by prolonged calcifying conditions by inhibiting osteogenic differentiation and increases in nSMase2 through Dectin1-independent actions involving Bβglucans internalization. Thus, dietary Bβglucans inhibit leukocyte superoxide production and leukocyte, renal and aortic ADAM17- and nSMase2 gene expression attenuating systemic inflammation in health, and renal injury and aortic calcification despite hyperphosphatemia in CKD.

Hypoxia Induces Macrophage tnfa Expression via Cyclooxygenase and Prostaglandin E2 in vivo

Macrophage phenotypes are poorly characterized in disease systems in vivo. Appropriate macrophage activation requires complex coordination of local microenvironmental cues and cytokine signaling. If the molecular mechanisms underpinning macrophage activation were better understood, macrophages could be pharmacologically tuned during disease situations. Here, using zebrafish tnfa:GFP transgenic lines as in vivo readouts, we show that physiological hypoxia and stabilization of Hif-1α promotes macrophage tnfa expression. We demonstrate a new mechanism of Hif-1α-induced macrophage tnfa expression via a cyclooxygenase/prostaglandin E2 axis. These findings uncover a macrophage HIF/COX/TNF axis that links microenvironmental cues to macrophage phenotype, with important implications during inflammation, infection, and cancer, where hypoxia is a common microenvironmental feature and where cyclooxygenase and TNF are major mechanistic players.

Proteases in Pemphigoid Diseases

Pemphigoid diseases are a subgroup of autoimmune skin diseases characterized by widespread tense blisters. Standard of care typically involves immunosuppressive treatments, which may be insufficient and are often associated with significant adverse events. As such, a deeper understanding of the pathomechanism(s) of pemphigoid diseases is necessary in order to identify improved therapeutic approaches. A major initiator of pemphigoid diseases is the accumulation of autoantibodies against proteins at the dermal-epidermal junction (DEJ), followed by protease activation at the lesion. The contribution of proteases to pemphigoid disease pathogenesis has been investigated using a combination of in vitro and in vivo models. These studies suggest proteolytic degradation of anchoring proteins proximal to the DEJ is crucial for dermal-epidermal separation and blister formation. In addition, proteases can also augment inflammation, expose autoantigenic cryptic epitopes, and/or provoke autoantigen spreading, which are all important in pemphigoid disease pathology. The present review summarizes and critically evaluates the current understanding with respect to the role of proteases in pemphigoid diseases.

The role of NF-κB and Elk-1 in the regulation of mouse ADAM17 expression

ADAM17 is a cell membrane metalloproteinase responsible for the release of ectodomains of numerous proteins from the cell surface. Although ADAM17 is often overexpressed in tumours and at sites of inflammation, little is known about the regulation of its expression. Here we investigate the role of NF-κB and Elk-1 transcription factors and upstream signalling pathways, NF-κB and ERK1/2 in ADAM17 expression in mouse brain endothelial cells stimulated with pro-inflammatory factors (TNF, IL-1β, LPS) or a phorbol ester (PMA), a well-known stimulator of ADAM17 activity. Notably, NF-κB inhibitor, IKK VII, interfered with the IL-1β- and LPS-mediated stimulation of ADAM17 expression. Furthermore, Adam17 promoter contains an NF-κB binding site occupied by p65 subunit of NF-κB. The transient increase in Adam17 mRNA in response to PMA was strongly reduced by an inhibitor of ERK1/2 phosphorylation, U0126. Luciferase reporter assay with vectors encoding the ERK1/2 substrate, Elk-1, fused with constitutively activating or repressing domains, indicated Elk-1 involvement in Adam17 expression. The site-directed mutagenesis of potential Elk-1 binding sites pointed to four functional Elk-1 binding sites in Adam17 promoter. All in all, our results indicate that NF-κB and Elk-1 transcription factors via NF-κB and ERK1/2 signalling pathways contribute to the regulation of mouse Adam17 expression.

Summary: We show the involvement of ERK1/2 and NF-κB pathways in the stimulation of mouse Adam17 expression and determine functional Elk-1- and NF-κB binding sites in its promoter.

Hif-1α-Induced Expression of Il-1β Protects against Mycobacterial Infection in Zebrafish

Drug-resistant mycobacteria are a rising problem worldwide. There is an urgent need to understand the immune response to tuberculosis to identify host targets that, if targeted therapeutically, could be used to tackle these currently untreatable infections. In this study we use an Il-1β fluorescent transgenic line to show that there is an early innate immune proinflammatory response to well-established zebrafish models of inflammation and Mycobacterium marinum infection. We demonstrate that host-derived hypoxia signaling, mediated by the Hif-1α transcription factor, can prime macrophages with increased levels of Il-1β in the absence of infection, upregulating neutrophil antimicrobial NO production, leading to greater protection against infection. Our data link Hif-1α to proinflammatory macrophage Il-1β transcription in vivo during early mycobacterial infection and importantly highlight a host protective mechanism, via antimicrobial NO, that decreases disease outcomes and that could be targeted therapeutically to stimulate the innate immune response to better deal with infections.

Hematopoietic hypoxia-inducible factor 2α deficiency ameliorates pathological retinal neovascularization via modulation of endothelial cell apoptosis

A hallmark of proliferative retinopathies, such as retinopathy of prematurity (ROP), is a pathological neovascularization orchestrated by hypoxia and the resulting hypoxia-inducible factor (HIF)-dependent response. We studied the role of Hif2α in hematopoietic cells for pathological retina neovascularization in the murine model of ROP, the oxygen-induced retinopathy (OIR) model. Hematopoietic-specific deficiency of Hif2α ameliorated pathological neovascularization in the OIR model, which was accompanied by enhanced endothelial cell apoptosis. That latter finding was associated with up-regulation of the apoptosis-inducer FasL in Hif2α-deficient microglia. Consistently, pharmacological inhibition of the FasL reversed the reduced pathological neovascularization from hematopoietic-specific Hif2α deficiency. Our study found that the hematopoietic cell Hif2α contributes to pathological retina angiogenesis. Our findings not only provide novel insights regarding the complex interplay between immune cells and endothelial cells in hypoxia-driven retina neovascularization but also may have therapeutic implications for proliferative retinopathies.-Korovina, I., Neuwirth, A., Sprott, D., Weber, S., Sardar Pasha, S. P. B., Gercken, B., Breier, G., El-Armouche, A., Deussen, A., Karl, M. O., Wielockx, B., Chavakis, T., Klotzsche-von Ameln, A. Hematopoietic hypoxia-inducible factor 2α deficiency ameliorates pathological retinal neovascularization via modulation of endothelial cell apoptosis.

ADAM-17 is expressed on rheumatoid arthritis fibroblast-like synoviocytes and regulates proinflammatory mediator expression and monocyte adhesion

Background

To examine the expression of ADAM-17 in rheumatoid arthritis (RA) biological fluids and the role it plays in monocyte adhesion to RA fibroblast-like synoviocytes (FLSs).

Methods

ADAM-17 expression was measured by enzyme-linked immunosorbent assays (ELISAs) in serum from normal (NL) subjects, osteoarthritis (OA) patients, and RA patients. We also analyzed the correlation between ADAM-17 and disease activity score 28 (DAS28) in RA. To determine expression of ADAM-17 in RA synovial tissues (STs) and RA FLS, we performed immunofluorescence analyses. To determine the role of ADAM-17 in RA, we transfected RA FLSs with small interfering RNA (siRNA) against ADAM-17. THP-1 adhesion to ADAM-17 siRNA-transfected RA FLSs was measured. Finally, adhesion molecules on ADAM-17 siRNA-transfected RA FLSs were measured using cell surface ELISAs.

Results

ADAM-17 in RA serum was significantly higher than that in NL and OA serum and correlated with DAS28. ADAM-17 in RA synovial fluids was higher than that in OA synovial fluids. ADAM-17 was expressed on RA cells lining STs and RA FLSs. THP-1 adhesion to ADAM-17 siRNA-transfected RA FLSs was decreased compared with that to control siRNA-transfected RA FLSs. ICAM-1 on TNF-α-stimulated ADAM-17 siRNA-transfected RA FLSs was significantly decreased compared with that on control siRNA-transfected RA FLSs.

Conclusions

These data indicate that ADAM-17 is expressed on RA STs and plays a role in RA inflammation by regulating monocyte adhesion to RA FLSs. ADAM-17 might be an important inflammatory mediator in inflammatory diseases such as RA.

The family of the interleukin-1 receptors

The extracellular forms of the IL-1 cytokines are active through binding to specific receptors on the surface of target cells. IL-1 ligands bind to the extracellular portion of their ligand-binding receptor chain. For signaling to take place, a non-binding accessory chain is recruited into a heterotrimeric complex. The intracellular approximation of the Toll-IL-1-receptor (TIR) domains of the 2 receptor chains is the event that initiates signaling. The family of IL-1 receptors (IL-1R) includes 10 structurally related members, and the distantly related soluble protein IL-18BP that acts as inhibitor of the cytokine IL-18. Over the years the receptors of the IL-1 family have been known with many different names, with significant confusion. Thus, we will use here a recently proposed unifying nomenclature. The family includes several ligand-binding chains (IL-1R1, IL-1R2, IL-1R4, IL-1R5, and IL-1R6), 2 types of accessory chains (IL-1R3, IL-1R7), molecules that act as inhibitors of signaling (IL-1R2, IL-1R8, IL-18BP), and 2 orphan receptors (IL-1R9, IL-1R10). In this review, we will examine how the receptors of the IL-1 family regulate the inflammatory and anti-inflammatory functions of the IL-1 cytokines and are, more at large, involved in modulating defensive and pathological innate immunity and inflammation. Regulation of the IL-1/IL-1R system in the brain will be also described, as an example of the peculiarities of organ-specific modulation of inflammation.

Expression of the ectodomain-releasing protease ADAM17 is directly regulated by the osteosarcoma and bone-related transcription factor RUNX2

Osteoblast differentiation is controlled by transcription factor RUNX2 which temporally activates or represses several bone-related genes, including those encoding extracellular matrix proteins or factors that control cell-cell, and cell-matrix interactions. Cell-cell communication in the many skeletal pericellular micro-niches is critical for bone development and involves paracrine secretion of growth factors and morphogens. This paracrine signaling is in part regulated by "A Disintegrin And Metalloproteinase" (ADAM) proteins. These cell membrane-associated metalloproteinases support proteolytic release ("shedding") of protein ectodomains residing at the cell surface. We analyzed microarray and RNA-sequencing data for Adam genes and show that Adam17, Adam10, and Adam9 are stimulated during BMP2 mediated induction of osteogenic differentiation and are robustly expressed in human osteoblastic cells. ADAM17, which was initially identified as a tumor necrosis factor alpha (TNFα) converting enzyme also called (TACE), regulates TNFα-signaling pathway, which inhibits osteoblast differentiation. We demonstrate that Adam17 expression is suppressed by RUNX2 during osteoblast differentiation through the proximal Adam17 promoter region (-0.4 kb) containing two functional RUNX2 binding motifs. Adam17 downregulation during osteoblast differentiation is paralleled by increased RUNX2 expression, cytoplasmic-nuclear translocation and enhanced binding to the Adam17 proximal promoter. Forced expression of Adam17 reduces Runx2 and Alpl expression, indicating that Adam17 may negatively modulate osteoblast differentiation. These findings suggest a novel regulatory mechanism involving a reciprocal Runx2-Adam17 negative feedback loop to regulate progression through osteoblast differentiation. Our results suggest that RUNX2 may control paracrine signaling through regulation of ectodomain shedding at the cell surface of osteoblasts by directly suppressing Adam17 expression.

ADAM-17 is expressed in the inflammatory myopathy and is involved with interstitial lung disease

The "A disintegrin and metalloprotease" (ADAM) family is thought to play an important role in tissue destruction and inflammatory reactions. ADAM-17 was first described as the protease responsible for tumor necrosis factor (TNF)-α shedding. Here, we have shown the expression of ADAM-17 in inflammatory myopathy and demonstrated the role of inflammation in interstitial lung diseases (ILD). ADAM-17 in inflammatory myopathy serum [polymyositis (n = 26), dermatomyositis (n = 34), and clinically amyopathic dermatomyositis (n = 10)] and healthy control (n = 19) was measured using enzyme-linked immunosorbent assay. The relationship between ADAM-17 and clinical data was examined. Finally, we performed immunohistological analysis to investigate the expression of ADAM-17 on the muscles of the inflammatory myopathy patients. ADAM-17 in inflammatory myopathy was significantly higher than that in healthy control (mean ± SEM, 1048 ± 312 and 36 ± 18 pg/ml, respectively; p < 0.05). ADAM-17 in post-treatment with corticosteroid and/or immunosuppressant serum was significantly decreased compared with that in pre-treatment serum (1465 ± 562 and 1059 ± 503 pg/ml, respectively; p < 0.01). ADAM-17 was significantly positively correlated with fractalkine/CX3CL1 and CXCL16. In addition, ADAM-17 in inflammatory myopathy with ILD patients (n = 46) was significantly higher than that in non-ILD patients (n = 24) (1379 ± 454 and 413 ± 226 pg/ml, respectively; p < 0.05). We found the expression of ADAM-17 on muscle biopsy tissue. ADAM-17 is expressed in inflammatory myopathies especially ILD, suggesting that ADAM-17 plays a role in lung fibrosis. ADAM-17 may be a potential target in inflammatory myopathies with ILD.

Anti-angiogenic effects of biotechnological therapies in rheumatic diseases

Introduction

Angiogenesis plays a key role in the pathogenesis of numerous rheumatic diseases, such as rheumatoid arthritis, psoriatic arthritis, and vasculitides. Therefore, the inhibition of pathological angiogenesis may be considered a useful therapeutical approach in these rheumatic diseases.

Methods

This review article is based on a literature research about the role of biotechnological therapies in angiogenesis inhibition.

Results and conclusions

Several evidences have demonstrated a role for biotechnological therapies in angiogenesis inhibition. Nevertheless, further research and clinical trials are needed to better quantify the real impact of biotechnological therapies on pathological angiogenesis.

Efferocytosis and Outside-In Signaling by Cardiac Phagocytes. Links to Repair, Cellular Programming, and Intercellular Crosstalk in Heart

Phagocytic sensing and engulfment of dying cells and extracellular bodies initiate an intracellular signaling cascade within the phagocyte that can polarize cellular function and promote communication with neighboring non-phagocytes. Accumulating evidence links phagocytic signaling in the heart to cardiac development, adult myocardial homeostasis, and the resolution of cardiac inflammation of infectious, ischemic, and aging-associated etiology. Phagocytic clearance in the heart may be carried out by professional phagocytes, such as macrophages, and non-professional cells, including myofibrolasts and potentially epithelial cells. During cardiac development, phagocytosis initiates growth cues for early cardiac morphogenesis. In diseases of aging, including myocardial infarction, heightened levels of cell death require efficient phagocytic debridement to salvage further loss of terminally differentiated adult cardiomyocytes. Additional risk factors, including insulin resistance and other systemic risk factors, contribute to inefficient phagocytosis, altered phagocytic signaling, and delayed cardiac inflammation resolution. Under such conditions, inflammatory presentation of myocardial antigen may lead to autoimmunity and even possible rejection of transplanted heart allografts. Increased understanding of these basic mechanisms offers therapeutic opportunities.

Hypoxia-induced mobilization of NHE6 to the plasma membrane triggers endosome hyperacidification and chemoresistance

The pH-dependent partitioning of chemotherapeutic drugs is a fundamental yet understudied drug distribution mechanism that may underlie the low success rates of current approaches to counter multidrug resistance (MDR). This mechanism is influenced by the hypoxic tumour microenvironment and results in selective trapping of weakly basic drugs into acidified compartments such as the extracellular environment. Here we report that hypoxia not only leads to acidification of the tumour microenvironment but also induces endosome hyperacidification. The acidity of the vesicular lumen, together with the alkaline pH of the cytoplasm, gives rise to a strong intracellular pH gradient that drives intravesicular drug trapping and chemoresistance. Endosome hyperacidification is due to the relocalization of the Na⁺/H⁺ exchanger isoform 6 (NHE6) from endosomes to the plasma membrane, an event that involves binding of NHE6 to the activated protein kinase C-receptor for activated C kinase 1 complex. These findings reveal a novel mechanism of hypoxia-induced MDR that involves the aberrant intracellular distribution of NHE6.

Hypoxia-induced ADAM 17 expression is mediated by RSK1-dependent C/EBPβ activation in human lung fibroblasts

Hypoxia was identified as a mediator of lung fibrosis in patients with chronic obstructive asthma (COA). Overexpression of a disintegrin and metalloproteinase 17 (ADAM 17) and connective tissue growth factor (CTGF) leads to development of tissue fibrosis. However, the signaling pathway in hypoxia-induced ADAM 17 expression remains poorly defined. In this study, we investigated the roles that ribosomal S-6 kinase 1 (RSK1)/CCAAT/enhancer-binding protein β (C/EBPβ)-dependent ADAM 17 expression plays in hypoxia-induced CTGF expression in human lung fibroblasts. We observed that hypoxia caused increases in ADAM 17 expression and ADAM 17-luciferase activity in WI-38 cells. Hypoxia-induced CTGF-luciferase activity and CTGF expression were reduced in cells transfected with small interfering (si)RNA of ADAM 17 in WI-38 cells. Moreover, hypoxia-induced ADAM 17 expression was reduced by RSK1 siRNA and C/EBPβ siRNA. Hypoxia caused time-dependent increases in RSK1 phosphorylation at Thr359/Ser363. Exposure of cells to hypoxia resulted in increased C/EBPβ phosphorylation at Thr266 and C/EBPβ-luciferase activity in time-dependent manners, and these effects were suppressed by RSK1 siRNA. Hypoxia induced recruitment of C/EBPβ to the ADAM 17 promoter. Furthermore, CTGF-luciferase activity induced by hypoxia was attenuated by RSK1 siRNA and C/EBPβ siRNA. These results suggest that hypoxia instigates the RSK1-dependent C/EBPβ signaling pathway, which in turn initiates binding of C/EBPβ to the ADAM 17 promoter and ultimately induces ADAM 17 expression in human lung fibroblasts. Moreover, RSK1/C/EBPβ-dependent ADAM 17 expression is involved in hypoxia-induced CTGF expression. Our results suggest possible therapeutic approaches for treating hypoxia-mediated lung fibrosis in COA.

Therapeutic effect of Cryptotanshinone on experimental rheumatoid arthritis through downregulating p300 mediated-STAT3 acetylation

BACKGROUND AND PURPOSE

The balance between T helper 17 (Th17) cells and regulatory T (Treg) cells, plays a critical role in rheumatoid arthritis (RA). The differentiation of Th17 cells requires the activation of STAT3, which determines the balance of Th17/Treg. Here, we investigated the therapeutic effect of Cryptotanshinone (CTS) on collagen induced mouse arthritis and explored the underlying mechanisms.

EXPERIMENTAL APPROACH

Arthritis was induced in DBA/1 mice with bovine collagen type II and complete Freund's adjuvant. CTS was given at 20mgkg^-1d^-1 or 60mgkg^-1d^-1 by gavage for 6weeks. The immuno-inflammation and joint destruction were evaluated and the balance of Th17/Treg was determined. STAT3 acetylation and phosphorylation were detected by western blotting, and the involvement of p300 was investigated by siRNA and plasmid overexpression.

KEY RESULTS

CTS at a dose of 60mgkg^-1d^-1 ameliorated the inflammation and joint destruction in CIA mice. It improved Th17/Treg imbalance, and inhibited both acetylation and phosphorylation of STAT3. CTS reduced p300 expression and its binding to STAT3, but increased phosphorylated AMPK. Knockdown of p300 mimicked the inhibitory effect of CTS on STAT3 acetylation and phosphorylation, which could be partially rescued by overexpression of p300-WT, but not p300-dominant negative (DN) construct.

CONCLUSION AND IMPLICATIONS

Our study suggested that the anti-arthritis effects of CTS were attained through suppression of p300-mediated STAT3 acetylation. Our data suggest that CTS might be a potential immune modulator for RA treatment.

Fibroblast-like synoviocytes-dependent effector molecules as a critical mediator for rheumatoid arthritis: Current status and future directions

Rheumatoid arthritis (RA) is a systemic-autoimmune-mediated disease characterized by synovial hyperplasia and progressive destruction of joint. Currently available biological agents and inhibitor therapy that specifically target tumor necrosis factor-α, interleukin 1β (IL-1β), IL-6, T cells, B cells, and subcellular molecules (p38 mitogen-activated protein kinase and janus kinase) cannot facilitate complete remission in all patients and are unable to cure the disease. Therefore, further potent therapeutic targets need to be identified for effective treatment and successful clinical outcomes in patients with RA. Scientific breakthroughs have brought new insights regarding fibroblast-like synoviocytes (FLS), a major constituent of the synovial hyperplasia. These play a pivotal role in RA invading cartilage and bone tissue. Currently there are no effective therapies available that specifically target these aggressive cells. Recent evidences indicate that FLS-dependent effector molecules (toll-like receptors, nodal effector molecules, hypoxia-inducible factor, and IL-17) have emerged as important mediators of RA. In this review, we discuss the pathological features and recent advances in understanding the role of FLS-dependent effector molecules in the disease onset of RA. Pharmacological inhibition of FLS-dependent effector molecules might be a promising option for FLS-targeted therapy in RA.

Inhibition of Notch pathway arrests PTEN-deficient advanced prostate cancer by triggering p27-driven cellular senescence

Activation of NOTCH signalling is associated with advanced prostate cancer and treatment resistance in prostate cancer patients. However, the mechanism that drives NOTCH activation in prostate cancer remains still elusive. Moreover, preclinical evidence of the therapeutic efficacy of NOTCH inhibitors in prostate cancer is lacking. Here, we provide evidence that PTEN loss in prostate tumours upregulates the expression of ADAM17, thereby activating NOTCH signalling. Using prostate conditional inactivation of both Pten and Notch1 along with preclinical trials carried out in Pten-null prostate conditional mouse models, we demonstrate that Pten-deficient prostate tumours are addicted to the NOTCH signalling. Importantly, we find that pharmacological inhibition of γ-secretase promotes growth arrest in both Pten-null and Pten/Trp53-null prostate tumours by triggering cellular senescence. Altogether, our findings describe a novel pro-tumorigenic network that links PTEN loss to ADAM17 and NOTCH signalling, thus providing the rational for the use of γ-secretase inhibitors in advanced prostate cancer patients.

Notch signalling is involved in prostate cancer progression and therapeutic resistance. Here, the authors show that loss of PTEN in prostate cancer models results in increased Notch1 cleavage and activation through CUX1-mediated transactivation of ADAM17.

Soluble TNF Regulates TACE via AP-2α Transcription Factor in Mouse Dendritic Cells

Dendritic cells (DCs), the essential immunoregulatory and APCs, are major producers of the central mediator of inflammation, soluble TNF-α (sTNF). sTNF is generated by TNF-α converting enzyme (TACE) proteolytic release of the transmembrane TNF (tmTNF) ectodomain. The mechanisms of TACE and sTNF regulation in DCs remain elusive. This study newly defines that sTNF regulates TACE in mouse DCs by engaging the AP-2α transcription factor. We found that the expression of AP-2α was higher, whereas the expression and activity of TACE were lower, in wild-type DCs (wtDCs) than in TNF knockout (TNFko) DCs. Exogenous sTNF rapidly and simultaneously induced increases of AP-2α expression and decreases of TACE expression and activity in wtDCs and TNFko DCs, indicating that AP-2α and TACE are inversely dependent on sTNF and are functionally associated. To define this functional association, we identified an AP-2α binding site in TACE promoter and demonstrated, using EMSAs and chromatin immunoprecipitation assays, that AP-2α could bind to TACE promoter in a TNF-dependent manner. Additionally, sTNF simultaneously enhanced AP-2α expression and decreased TACE promoter luciferase activity in DCs. Similarly, transfection of AP-2α cDNA decreased TACE promoter luciferase activity, TACE expression, and TACE enzymatic activity in wtDCs or TNFko DCs. In contrast, transfection of AP-2α small interfering RNA increased TACE promoter luciferase activity, TACE expression, and TACE enzymatic activity in wtDCs. These results show that TACE is a target of, and is downregulated by, sTNF-induced AP-2α transcription factor in DCs.

Influence of Extracellular RNAs, Released by Rheumatoid Arthritis Synovial Fibroblasts, on Their Adhesive and Invasive Properties

Extracellular RNA (exRNA) has been characterized as a molecular alarm signal upon cellular stress or tissue injury and to exert biological functions as a proinflammatory, prothrombotic, and vessel permeability-regulating factor. In this study, we investigated the contribution of exRNA and its antagonist RNase1 in a chronic inflammatory joint disease, rheumatoid arthritis (RA). Upon immunohistochemical inspection of RA, osteoarthritis (OA), and psoriatic arthritis synovium, exRNA was detectable only in the RA synovial lining layer, whereas extracellular DNA was detectable in various areas of synovial tissue. In vitro, exRNA (150-5000 nt) was released by RA synovial fibroblasts (RASF) under hypoxic conditions but not under normoxia or TNF-α treatment. RNase activity was increased in synovial fluid from RA and OA patients compared with psoriatic arthritis patients, whereas RNase activity of RASF and OASF cultures was not altered by hypoxia. Reduction of exRNA by RNase1 treatment decreased adhesion of RASF to cartilage, but it had no influence on their cell proliferation or adhesion to endothelial cells. In vivo, treatment with RNase1 reduced RASF invasion into coimplanted cartilage in the SCID mouse model of RA. We also analyzed the expression of neuropilins in synovial tissue and SF, as they may interact with vascular endothelial growth factor signaling and exRNA. The data support the concepts that the exRNA/RNase1 system participates in RA pathophysiology and that RASF are influenced by exRNA in a prodestructive manner.

Effects of depression and inflammatory factors on chronic conditions of the wrist

Aims

Chronic conditions of the wrist may be difficult to manage because pain and psychiatric conditions are correlated with abnormal function of the hand. Additionally, intra-articular inflammatory cytokines may cause pain. We aimed to validate the measurement of inflammatory cytokines in these conditions and identify features associated with symptoms.

Patients and Methods

The study included 38 patients (18 men, 20 women, mean age 43 years) with a chronic condition of the wrist who underwent arthroscopy. Before surgery, the Self-Rating Depression Scale (SDS), Hand20 questionnaire and a visual analogue scale (VAS) for pain were used. Cytokine and chemokine levels in the synovial fluid of the wrist were measured using enzyme-linked immunosorbent assays and correlations between the levels with pain were analysed. Gene expression profiles of the synovial membranes were assessed using quantitative polymerase chain reaction.

Results

Older patients had high pre-operative Hand20 scores. One-year post-operative Hand20 and VAS scores and pre-operative VAS scores correlated with SDS scores. Post-operative VAS scores negatively correlated with the expression of nerve growth factor and SDS scores positively correlated with the expression of tumour necrosis factor-alpha and negatively correlated with the expression of tumour necrosis factor-converting enzyme.

Conclusion

There was a positive correlation between depression and chronic conditions of the wrist. Levels of some cytokines correlate with pain and depression. Additionally, cytokines may be important in the assessment and treatment of chronic conditions of the wrist and depression. Cite this article: Bone Joint J 2016;98-B:961–8.

Hypoxia-Inducible Factor (HIF) as a Target for Novel Therapies in Rheumatoid Arthritis

Hypoxia is an important micro-environmental characteristic of rheumatoid arthritis (RA). Hypoxia-inducible factors (HIF) are key transcriptional factors that are highly expressed in RA synovium to regulate the adaptive responses to this hypoxic milieu. Accumulating evidence supports hypoxia and HIFs in regulating a number of important pathophysiological characteristics of RA, including synovial inflammation, angiogenesis, and cartilage destruction. Experimental and clinical data have confirmed the upregulation of both HIF-1α and HIF-2α in RA. This review will focus on the differential expression of HIFs within the synovial joint and its functional behavior in different cell types to regulate RA progression. Potential development of new therapeutic strategies targeting HIF-regulated pathways at sites of disease in RA will also be addressed.

A disintegrin and metalloprotease-17 and galectin-9 are important regulators of local 4-1BB activity and disease outcome in rheumatoid arthritis

OBJECTIVE

Co-stimulatory T cell cytokines are important in the progression of RA. This study investigates the interplay between 4-1BB, a disintegrin and metalloprotease-17 (ADAM17) and galectin-9 (Gal-9) in RA.

METHODS

Stimulated mononuclear cells from patients with chronic RA (n = 12) were co-incubated with tissue inhibitor of metalloproteinase, 4-1BB ligand and Gal-9. Plasma samples were examined for soluble 4-1BB (s4-1BB) in newly diagnosed, treatment-naïve patients with RA (n = 97). The 28-joint DAS with CRP (28DAS-CRP), total Sharp score, erosion score and joint space narrowing were used to evaluate treatment outcome serially over a 2-year period.

RESULTS

RA CD4(+) and CD8(+) synovial T cells express high levels of 4-1BB. The addition of TNF-α to cultured synovial mononuclear cells increased shedding of 4-1BB. 4-1BB ligand only increased TNF-α shedding in combination with Gal-9. RNA interference-mediated knockdown of ADAM17 or the addition of an ADAM17 inhibitor reduced the 4-1BB shedding. Shedding of 4-1BB was not influenced by Gal-9. Plasma levels of s4-1BB were increased in early RA and correlated with the number of swollen joints at baseline. After 3 months of treatment, the plasma levels of s4-1BB were equal to those of the controls. Baseline plasma levels of s4-1BB were inversely correlated with DAS28-CRP after 2 years of treatment, but not with total Sharp score, erosion score or joint space narrowing.

CONCLUSION

ADAM17 induces 4-1BB shedding in RA. Gal-9 is pivotal for the function of 4-1BB and induction of TNF-α. Furthermore, high plasma levels of s4-1BB were associated with the number of swollen joints, but also with a low DAS28-CRP after 2 years treatment in early RA.

Epithelial Cell-Derived a Disintegrin and Metalloproteinase-17 Confers Resistance to Colonic Inflammation Through EGFR Activation

Epithelial regeneration is a key process for the recovery from ulcerative colitis (UC). Here we demonstrate that a disintegrin and metalloproteinase-17 (ADAM17), a main sheddase for tumor necrosis factor (TNF)-α, is essential for defensive epithelial properties against UC by promoting epithelial cell growth and goblet cell differentiation in mouse and human. Mice with systemic deletion of Adam17 developed severe dextran sulfate sodium-induced colitis when compared to mice with myeloid cell Adam17 deletion or control littermates. ADAM17 was predominantly expressed by regenerating epithelia in control mice, and its loss or inhibition attenuated epidermal growth factor receptor (EGFR) activation, epithelial proliferation, mucus production and barrier functions. Conversely, ectopic EGFR stimulation promoted epithelial regeneration thereby partially rescuing the severe colitis caused by ADAM17 deficiency. In UC patients, epithelial ADAM17 expression positively correlated with both cell proliferation and goblet cell number. These findings suggest that maintaining ADAM17–EGFR epithelial signaling is necessary for the recovery from UC and would be beneficial to therapeutic strategies targeting ADAM17-mediated TNF-α shedding.

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Mice with systemic deletion of ADAM17, but not with its myeloid cell-specific deficiency, are more sensitive to colitis.

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ADAM17-EGFR axis promotes repair processes through epithelial cell proliferation and goblet cell differentiation.

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Epithelial ADAM17 expression correlates with cell growth and mucus production in ulcerative colitis patients.

Epithelial regeneration is a key process for the recovery from ulcerative colitis (UC). We now demonstrate that a disintegrin and metalloproteinase-17 (ADAM17) is essential for defensive epithelial properties against UC by driving repair processes in mouse and human. During colonic inflammation, ADAM17 is up-regulated in regenerating epithelia, and its loss or inhibition attenuated epidermal growth factor receptor (EGFR) activation, epithelial proliferation, mucus production and barrier functions. These findings suggest that maintaining ADAM17–EGFR epithelial signaling is necessary for the recovery from UC and would be beneficial to therapeutic strategies targeting ADAM17-mediated tumor necrosis factor-α shedding.

Arsenic Promotes NF-Κb-Mediated Fibroblast Dysfunction and Matrix Remodeling to Impair Muscle Stem Cell Function

Arsenic is a global health hazard that impacts over 140 million individuals worldwide. Epidemiological studies reveal prominent muscle dysfunction and mobility declines following arsenic exposure; yet, mechanisms underlying such declines are unknown. The objective of this study was to test the novel hypothesis that arsenic drives a maladaptive fibroblast phenotype to promote pathogenic myomatrix remodeling and compromise the muscle stem (satellite) cell (MuSC) niche. Mice were exposed to environmentally relevant levels of arsenic in drinking water before receiving a local muscle injury. Arsenic-exposed muscles displayed pathogenic matrix remodeling, defective myofiber regeneration and impaired functional recovery, relative to controls. When naïve human MuSCs were seeded onto three-dimensional decellularized muscle constructs derived from arsenic-exposed muscles, cells displayed an increased fibrogenic conversion and decreased myogenicity, compared with cells seeded onto control constructs. Consistent with myomatrix alterations, fibroblasts isolated from arsenic-exposed muscle displayed sustained expression of matrix remodeling genes, the majority of which were mediated by NF-κB. Inhibition of NF-κB during arsenic exposure preserved normal myofiber structure and functional recovery after injury, suggesting that NF-κB signaling serves as an important mechanism of action for the deleterious effects of arsenic on tissue healing. Taken together, the results from this study implicate myomatrix biophysical and/or biochemical characteristics as culprits in arsenic-induced MuSC dysfunction and impaired muscle regeneration. It is anticipated that these findings may aid in the development of strategies to prevent or revert the effects of arsenic on tissue healing and, more broadly, provide insight into the influence of the native myomatrix on stem cell behavior.

Snail Is a Critical Mediator of Invadosome Formation and Joint Degradation in Arthritis

Progressive cartilage destruction, mediated by invasive fibroblast-like synoviocytes, is a central feature in the pathogenesis of rheumatoid arthritis (RA). Members of the Snail family of transcription factors are required for cell migration and invasion, but their role in joint destruction remains unknown. Herein, we demonstrate that Snail is essential for the formation of extracellular matrix-degrading invadosomal structures by synovial cells from collagen-induced arthritis (CIA) rats and RA patients. Mechanistically, Snail induces extracellular matrix degradation in synovial cells by repressing PTEN, resulting in increased phosphorylation of platelet-derived growth factor receptor and activation of the phosphatidylinositol 3-kinase/AKT pathway. Of significance, Snail is overexpressed in synovial cells and tissues of CIA rats and RA patients, whereas knockdown of Snail in CIA joints prevents cartilage invasion and joint damage. Furthermore, Snail expression is associated with an epithelial-mesenchymal transition gene signature characteristic of transglutaminase 2/transforming growth factor-β activation. Transforming growth factor-β and transglutaminase 2 stimulate Snail-dependent invadosome formation in rat and human synoviocytes. Our results identify the Snail-PTEN platelet-derived growth factor receptor/phosphatidylinositol 3-kinase axis as a novel regulator of the prodestructive invadosome-forming phenotype of synovial cells. New therapies for RA target inflammation, and are only partly effective in preventing joint damage. Blocking Snail and/or its associated gene expression program may provide an additional tool to improve the efficacy of treatments to prevent joint destruction.