Mir-155 is overexpressed in systemic sclerosis fibroblasts and is required for NLRP3 inflammasome-mediated collagen synthesis during fibrosis.

BACKGROUND: Despite the important role that microRNAs (miRNAs) play in immunity and inflammation, their involvement in systemic sclerosis (SSc) remains poorly characterized. miRNA-155 (miR-155) plays a role in pulmonary fibrosis and its expression can be induced with interleukin (IL)-1ß. SSc fibroblasts have activated inflammasomes that are integrally involved in mediating the myofibroblast phenotype. In light of this, we investigated whether miR-155 played a role in SSc and if its expression was dependent on inflammasome activation. METHODS: miR-155 expression was confirmed in SSc dermal and lung fibroblasts by quantitative polymerase chain reaction (PCR). Wild-type and NLRP3-deficient murine fibroblasts were utilized to explore the regulation of miR-155 during inflammasome activation. miR-155-deficient fibroblasts and retroviral transductions with a miR-155 expression or control vectors were used to understand the contribution of miR-155 in fibrosis. RESULTS: miR-155 was significantly increased and the highest expressing miRNA in SSc lung fibroblasts. Its expression was dependent on inflammasome activation as miR-155 expression could be blocked when inflammasome signaling was inhibited. In the absence of miR-155, inflammasome-mediated collagen synthesis could not be induced but was restored when miR-155 was expressed in miR-155-deficient fibroblasts. CONCLUSIONS: miR-155 is upregulated in SSc. These results suggest that the inflammasome promotes the expression of miR-155 and that miR-155 is a critical miRNA that drives fibrosis.

Chimeric cells of maternal origin do not appear to be pathogenic in the juvenile idiopathic inflammatory myopathies or muscular dystrophy.

INTRODUCTION: Microchimeric cells have been studied for over a decade, with conflicting reports on their presence and role in autoimmune and other inflammatory diseases. To determine whether microchimeric cells were pathogenic or mediating tissue repair in inflammatory myopathies, we phenotyped and quantified microchimeric cells in juvenile idiopathic inflammatory myopathies (JIIM), muscular dystrophy (MD), and noninflammatory control muscle tissues. METHOD: Fluorescence immunophenotyping for infiltrating cells with sequential fluorescence in situ hybridization was performed on muscle biopsies from ten patients with JIIM, nine with MD and ten controls. RESULTS: Microchimeric cells were significantly increased in MD muscle (0.079 ± 0.024 microchimeric cells/mm(2) tissue) compared to controls (0.019 ± 0.007 cells/mm(2) tissue, p = 0.01), but not elevated in JIIM muscle (0.043 ± 0.015 cells/mm(2)). Significantly more CD4+ and CD8+ microchimeric cells were in the muscle of patients with MD compared with controls (mean 0.053 ± 0.020/mm(2) versus 0 ± 0/mm(2) p = 0.003 and 0.043 ± 0.023/mm(2) versus 0 ± 0/mm(2) p = 0.025, respectively). No differences in microchimeric cells between JIIM, MD, and noninflammatory controls were found for CD3+, Class II+, CD25+, CD45RA+, and CD123+ phenotypes, and no microchimeric cells were detected in CD20, CD83, or CD45RO populations. The locations of microchimeric cells were similar in all three conditions, with MD muscle having more microchimeric cells in perimysial regions than controls, and JIIM having fewer microchimeric muscle nuclei than MD. Microchimeric inflammatory cells were found, in most cases, at significantly lower proportions than autologous cells of the same phenotype. CONCLUSIONS: Microchimeric cells are not specific to autoimmune disease, and may not be important in muscle inflammation or tissue repair in JIIM.

The Tsk2/+ mouse fibrotic phenotype is due to a gain-of-function mutation in the PIIINP segment of the Col3a1 gene.

Systemic sclerosis (SSc) is a polygenic, autoimmune disorder of unknown etiology, characterized by the excessive accumulation of extracellular matrix (ECM) proteins, vascular alterations, and autoantibodies. The tight skin (Tsk)2/+ mouse model of SSc demonstrates signs similar to SSc including tight skin and excessive deposition of dermal ECM proteins. By linkage analysis, we mapped the Tsk2 gene mutation to <3 megabases on chromosome 1. We performed both RNA sequencing of skin transcripts and genome capture DNA sequencing of the region spanning this interval in Tsk2/+ and wild-type littermates. A missense point mutation in the procollagen III amino terminal propeptide segment (PIIINP) of collagen, type III, alpha 1 (Col3a1) was found to be the best candidate for Tsk2; hence, both in vivo and in vitro genetic complementation tests were used to prove that this Col3a1 mutation is the Tsk2 gene. All previously documented mutations in the human Col3a1 gene are associated with the Ehlers-Danlos syndrome, a connective tissue disorder that leads to a defect in type III collagen synthesis. To our knowledge, the Tsk2 point mutation is the first documented gain-of-function mutation associated with Col3a1, which leads instead to fibrosis. This discovery provides insight into the mechanism of skin fibrosis manifested by Tsk2/+ mice.

Targeting the unfolded protein response, XBP1, and the NLRP3 inflammasome in fibrosis and cancer.

Increasing health care costs in the US are due in a large part to the increasing prevalence of chronic diseases in an aging population. Current therapeutic strategies for treating chronic diseases alleviate symptoms allowing patients to live longer with these diseases, but they do little, however, to alter the underlying disease course. Recent advances in molecular biology are revealing new drug targets that may significantly alter the course of these diseases and, as a result, offer economic relief from burgeoning health care costs. Endoplasmic reticulum (ER) stress has been implicated as an underlying pathology in many chronic diseases, and, therefore, the development of therapies designed to ameliorate ER stress may yield novel, effective treatment strategies. Herein, we report that X-box binding protein 1 (XBP1) may be one of the earliest proteins engaged in response to ER stress. We show that a new signaling peptide derived from the ER-embedded transient receptor potential calcium channel protein 1 (TRPC1) engages XBP1 upstream of NLRP3 inflammasome-mediated maturation and secretion of IL-1ß/IL-18. Moreover, we show that a synthetic homolog of this signaling peptide (Naclynamide™) administered intravenously twice weekly over a 4-week treatment course induced suppuration and evoked partial or complete resolution of lesions associated with a fibrotic granuloma, a lymphosarcoma, and a colo-rectal carcinoma in canine patients. The mode of action for Naclynamide™ as a first-in-class anti-cancer drug candidate is discussed.

Two α-dicarbonyls downregulate migration, invasion, and adhesion of liver cancer cells in a p53-dependent manner.

BACKGROUND: Hepatocellular carcinoma accounts for more than 600,000 deaths per year due to it being a highly invasive tumor. The α-dicarbonyl, methylglyoxal demonstrates efficacy at reducing tumor burden, however the anti-cancerous activities of 3-deoxyglucosone, have never been studied. AIMS: To determine the anti-cancerous potential of methylglyoxal and 3-deoxyglucosone on liver tumor cells. METHODS: The in vitro effects of methylglyoxal and 3-deoxyglucosone were studied by investigating migration, invasion, and adhesion of Huh-7, HepG2, and Hep3B cells. RESULTS: 3-Deoxyglucosone inhibited migration of Huh-7 and HepG2 cells. Methylglyoxal decreased migration of HepG2 cells. Additionally, 3-deoxyglucosone and methylglyoxal impaired invasion, and adhesion of Huh-7 and HepG2 cells. In Hep3B cells, a p53 null cell line, 3-deoxyglucosone and methylglyoxal had no effect on migration, invasion, or adhesion. However, both compounds inhibited invasion of wild-type p53 transfected Hep3B cells. Silencing of p53 in Huh-7 and HepG2 cells abrogated the effects of the α-dicarbonyls on cell invasion. 3DG and MG did not alter p53 total protein but promoted nuclear translocation of p53. CONCLUSIONS: These studies suggest that 3-deoxyglucosone and methylglyoxal impair invasion, migration, and adhesion of hepatocellular carcinoma. The effects of both compounds on cell invasion are dependent on p53 and imply that α-dicarbonyls could be efficacious in the treatment of p53-expressing invasive liver tumors.

NLRP3 inflammasome is a target for development of broad-spectrum anti-infective drugs.

We describe the molecular mode of action and pharmacodynamics of a new molecular entity (NME) that induces the NLRP3 inflammasome-mediated innate immune response. This innate response reduces the pathogen load in an experimentally induced methicillin-resistant Staphylococcos aureus infection, enhances survival in an experimentally induced Gram-negative bacteremia, and overrides the escape mechanism of an obligate intracellular pathogen, viz. Chlamydia pneumoniae. Furthermore, the NME is more effective than standard-of-care antibiotic therapy in a clinically established multifactorial bacterial infection. Analysis of transcriptional regulation of inflammasome signaling genes and innate/adaptive immune genes revealed consistent and significant host changes responsible for the improved outcomes in these infections. These studies pave the way for the development of first-in-class drugs that enhance inflammasome-mediated pathogen clearance and identify the NLRP3 inflammasome as a drug target to address the global problem of emerging new infectious diseases and the reemergence of old diseases in an antibiotic-resistant form.

The inflammasome activating caspase 1 mediates fibrosis and myofibroblast differentiation in systemic sclerosis.

OBJECTIVE: Systemic sclerosis (SSc) is a chronic idiopathic disease of unknown etiology that is characterized by fibrosis of the skin and visceral organs mediated by activated myofibroblasts. The recently identified inflammasomes are cytosolic receptors that tightly regulate the activity of caspase 1 and downstream signaling molecules such as interleukin-1ß (IL-1ß) and IL-18. The nucleotide-binding oligomerization domain (NOD)-like receptor 3 (NLRP3) inflammasome has been implicated in the development of idiopathic pulmonary fibrosis. This study was undertaken to assess the role of the inflammasome in SSc-related dermal or pulmonary fibrosis. METHODS: Inflammasome gene transcripts were assayed in fibroblasts obtained from patients with SSc. Caspase 1 activation in SSc primary dermal and lung fibroblasts was inhibited, and the levels of hydroxyproline, COL1A1, COL3A1, IL-1ß, IL-18, and α-smooth muscle actin (α-SMA) were measured. The role of the inflammasome in dermal fibrosis was investigated in NLRP3(-/-) and ASC(-/-) mice. RESULTS: We identified increased expression of 40 genes associated with the inflammasome or downstream signaling molecules in SSc fibroblasts. Inhibition of caspase 1 in SSc dermal and lung fibroblasts abrogated the secretion of collagens, IL-1ß, and IL-18. In addition, we observed decreased expression of the myofibroblast protein α-SMA in SSc dermal fibroblasts treated with a caspase 1 inhibitor. Furthermore, NLRP3(-/-) mice and ASC(-/-) mice were resistant to bleomycin-induced skin fibrosis, which suggests a key role for the inflammasome in in vivo fibrosis. CONCLUSION: Innate immune signaling contributes to SSc fibrosis via activation of the inflammasome and caspase 1. These results suggest that inflammasome activation may play an important role in the pathogenesis of SSc.

Rapid sporulation of Bacillus anthracis in a high iron, glucose-free medium.

Spores are the infectious form of Bacillus anthracis (BA), causing cutaneous, inhalation and gastrointestinal anthrax. Because of the possible use of BA spores in a bioterrorism attack, there is considerable interest in studying spore biology. In the laboratory, however, it takes a number of days to prepare spores. Standard sporulation protocols, such as the use of 'PA broth', allow sporulation of BA to occur in 3 to 5 days. Another method employs growth of BA on plates in the dark for several days until they have efficiently sporulated. In efforts to determine the effect of iron on gene expression in BA, we grew BA Sterne strain 7702 in a minimal defined medium (CDM; Koppisch et al., 2005) with various concentrations of iron and glucose. As part of our initial observations, we monitored BA sporulation in CDM via light microscopy. In glucose-free CDM containing 1.5mM Fe(NO(3))(3) (CDM-Fe), >95% of the BA sporulated by 30 h; a far shorter time period than expected. We pursued this observation and we further characterized spores derived from PA and CDM-Fe media. Purified spores derived from PA or CDM-Fe had similar morphologies when viewed by light or electron microscopy, and were equally resistant to harsh conditions including heat (65 degrees C), ice and fresh 30% H(2)O(2). Spore viability in long term cold storage in water was similar for the two spore preparations. Extracted spore coat proteins were evaluated by SDS-PAGE and silver staining, which revealed distinct protein profiles for PA and CDM-Fe spore coat extracts. ELISA assays were done to compare the interaction of the two spore preparations with rabbit antiserum raised against UV-killed Sterne strain 7702 spores prepared in PA medium. Spores from both media reacted identically with this antiserum. Finally, the interaction and fate of spores incubated with macrophages in vitro was very similar. In summary, BA spores induced in CDM-Fe or in PA medium are similar by several criteria, but show distinct extractable coat proteins. CDM-Fe liquid medium can be used for rapid production of BA spores, and could save considerable time in spore research studies.

Two dicarbonyl compounds, 3-deoxyglucosone and methylglyoxal, differentially modulate dermal fibroblasts.

Advanced glycation endproducts accumulate on long-lived proteins such as collagens as a function of diet and age and mediate the cross-linking of those proteins causing changes in collagen pathophysiology resulting in the disruption of normal collagen matrix remodeling. Two commonly studied advanced glycation endproduct precursors 3-deoxyglucosone and methylglyoxal were investigated for their role in the modification of collagen and on extracellular matrix expression. Fibroblasts cultured on methylglyoxal cross-linked matrices increased the expression of collagen, active TGF-beta1, beta1-integrin, and decreased Smad7; whereas 3-deoxyglucosone decreased collagen, active TGF-beta1, beta1-integrin but increased Smad7. Purified collagen modified by 3-deoxyglucosone or methylglyoxal had different molecular weights; methylglyoxal increased the apparent molecular weight by approximately 20 kDa, whereas 3-deoxyglucosone did not. The differences in collagen expression by 3-deoxyglucosone and methylglyoxal raise the provocative idea that a genetic or environmental background leading to the predominance of one of these advanced glycation endproduct precursors may precipitate a fibrotic or chronic wound in susceptible individuals, particularly in the diabetic.

1-Peptidyl-2-arachidonoyl-3-stearoyl-sn-glyceride: an immunologically active lipopeptide from goat serum (Capra hircus) is an endogenous damage-associated molecular pattern.

Experiments were undertaken to isolate a component of the serum of goat (Capra hircus) that is effective at mediating an innate immune response. This report describes the isolation and structure elucidation of 1-(N-acetyl-ALYDKGYTSKEQKDCVGI)-2-arachidonoyl-3-stearoyl glyceride (1) and its immunomodulatory activity. A dose-response relationship for inflammatory cytokine and chemokine production and release from human fibroblasts incubated with nanomolar concentrations of 1 was shown. Moreover, the membrane transport role of the diacylglycerol moiety in 1 is demonstrated with nanomolar quantities of the transfected N-acetyl peptide moiety of 1 also inducing inflammatory cytokine and chemokine production and release. The apparent EC99 for 1 was 3 ng/mL (1 nM). The likely biological role for naturally occurring 1 as a damage-associated molecular pattern is postulated.

Bactericidal activity of chlorine-loaded carbide-derived carbon against Escherichia coli and Bacillus anthracis.

The authors investigated the bactericidal activity of high-chlorine-content nanoporous carbide-derived carbon (CDC) against the Gram-positive, spore-forming bacterium Bacillus anthracis and the common Gram-negative enteric bacterium Escherichia coli. Chlorine-loaded nanoporous CDC produced by thermochemical etching of metals and metalloids by chlorination of carbides can retain up to 40 wt % of chlorine. Etching temperature and the structure and composition of carbides allow tuning the porosity of CDC. The CDC chlorine content depends on the synthesis temperature, pore size, and metal carbide used during preparation. It was observed that chlorine-loaded CDC killed up to 100% of exposed E. coli and B. anthracis spores and vegetative cells in a dose and time-dependent manner. CDC containing higher concentrations of chlorine killed bacteria to a greater extent and faster than did CDC containing lesser concentrations of chlorine. The results suggest that chlorine-loaded CDC can be used in several commercial, defense, and industrial activities and processes to kill bacteria.