Role of MMPs in orchestrating inflammatory response in human monocytes via a TREM-1-PI3K-NF-κB pathway

Training vs. Tolerance: The Yin/Yang of the Innate Immune System

For almost nearly a century, memory functions have been attributed only to acquired immune cells. Lately, this paradigm has been challenged by an increasing number of studies revealing that innate immune cells are capable of exhibiting memory-like features resulting in increased responsiveness to subsequent challenges, a process known as trained immunity (known also as innate memory). In contrast, the refractory state of endotoxin tolerance has been defined as an immunosuppressive state of myeloid cells portrayed by a significant reduction in the inflammatory capacity. Both training as well tolerance as adaptive features are reported to be accompanied by epigenetic and metabolic alterations occurring in cells. While training conveys proper protection against secondary infections, the induction of endotoxin tolerance promotes repairing mechanisms in the cells. Consequently, the inappropriate induction of these adaptive cues may trigger maladaptive effects, promoting an increased susceptibility to secondary infections-tolerance, or contribute to the progression of the inflammatory disorder-trained immunity. This review aims at the discussion of these opposing manners of innate immune and non-immune cells, describing the molecular, metabolic and epigenetic mechanisms involved and interpreting the clinical implications in various inflammatory pathologies.

sTREM-1 promotes the phagocytic function of microglia to induce hippocampus damage via the PI3K-AKT signaling pathway

Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) is a soluble form of TREM-1 released during inflammation. Elevated sTREM-1 levels have been found in neuropsychiatric systemic lupus erythematosus (NPSLE) patients; yet, the exact mechanisms remain unclear. This study investigated the role of sTREM-1 in brain damage and its underlying mechanism. The sTREM-1 recombinant protein (2.5 μg/3 μL) was injected into the lateral ventricle of C57BL/6 female mice. After intracerebroventricular (ICV) injection, the damage in hippocampal neurons increased, and the loss of neuronal synapses and activation of microglia increased compared to the control mice (treated with saline). In vitro. after sTREM-1 stimulation, the apoptosis of BV2 cells decreased, the polarization of BV2 cells shifted to the M1 phenotype, the phagocytic function of BV2 cells significantly improved, while the PI3K-AKT signal pathway was activated in vivo and in vitro. PI3K-AKT pathway inhibitor LY294002 reversed the excessive activation and phagocytosis of microglia caused by sTREM-1 in vivo and in vitro, which in turn improved the hippocampus damage. These results indicated that sTREM-1 activated the microglial by the PI3K-AKT signal pathway, and promoted its excessive phagocytosis of the neuronal synapse, thus inducing hippocampal damage. sTREM-1 might be a potential target for inducing brain lesions.

Lung development, repair and cancer: A study on the role of MMP20 gene in adenocarcinoma

Multiple matrix metalloproteinases have significant roles in tissue organization during lung development, and repair. Imbalance of proteinases may lead to chronic inflammation, changes in tissue structure, and are also highly associated to cancer development. The role of MMP20 is not well studied in lung organogenesis, however, it was previously shown to be present at high level in lung adenocarcinoma. The current study aimed to identify the functional properties of MMP20 on cell proliferation and motility in a lung adenocarcinoma in vitro cell model, and relate the interaction of MMP20 with other molecular signalling pathways in the lung cells after gaining tumoral properties. In this study, two different single guide RNA (sgRNAs) that specifically targeted on MMP20 sites were transfected into human lung adenocarcinoma A549 cells by using CRISPR-Cas method. Following that, the changes of PI3-K, survivin, and MAP-K mRNA gene expression were determined by Real-Time Polymerase Chain Reaction (RT-PCR). The occurrence of cell death was also examined by Acridine Orange/Propidium Iodide double staining. Meanwhile, the motility of the transfected cells was evaluated by wound healing assay. All the data were compared with non-transfected cells as a control group. Our results demonstrated that the transfection of the individual sgRNAs significantly disrupted the proliferation of the A549 cell line through suppression in the gene expression of PI3-K, survivin, and MAP-K. When compared to non-transfected cells, both experimental cell groups showed reduction in the migration rate, as reflected by the wider gaps in the wound healing assay. The current study provided preliminary evidence that MMP20 could have regulatory role on stemness and proliferative genes in the lung tissues and affect the cell motility. It also supports the notion that targeting MMP20 could be a potential treatment mode for halting cancer progression.

Targeting the eCIRP/TREM-1 interaction with a small molecule inhibitor improves cardiac dysfunction in neonatal sepsis

Background

Neonatal sepsis and the associated myocardial dysfunction remain a leading cause of infant mortality. Extracellular cold-inducible RNA-binding protein (eCIRP) acts as a ligand of triggering receptor expressed on myeloid cells-1 (TREM-1). M3 is a small CIRP-derived peptide that inhibits the eCIRP/TREM-1 interaction. We hypothesize that the eCIRP/TREM-1 interaction in cardiomyocytes contributes to sepsis-induced cardiac dysfunction in neonatal sepsis, while M3 is cardioprotective.

Methods

Serum was collected from neonates in the Neonatal Intensive Care Unit (NICU). 5–7-day old C57BL/6 mouse pups were used in this study. Primary murine neonatal cardiomyocytes were stimulated with recombinant murine (rm) CIRP with M3. TREM-1 mRNA and supernatant cytokine levels were assayed. Mitochondrial oxidative stress, ROS, and membrane potential were assayed. Neonatal mice were injected with rmCIRP and speckle-tracking echocardiography was conducted to measure cardiac strain. Sepsis was induced by i.p. cecal slurry. Mouse pups were treated with M3 or vehicle. After 16 h, echocardiography was performed followed by euthanasia for tissue analysis. A 7-day survival study was conducted.

Results

Serum eCIRP levels were elevated in septic human neonates. rmCIRP stimulation of cardiomyocytes increased TREM-1 gene expression. Stimulation of cardiomyocytes with rmCIRP upregulated TNF-α and IL-6 in the supernatants, while this upregulation was inhibited by M3. Stimulation of cardiomyocytes with rmCIRP resulted in a reduction in mitochondrial membrane potential (MMP) while M3 treatment returned MMP to near baseline. rmCIRP caused mitochondrial calcium overload; this was inhibited by M3. rmCIRP injection impaired longitudinal and radial cardiac strain. Sepsis resulted in cardiac dysfunction with a reduction in cardiac output and left ventricular end diastolic diameter. Both were improved by M3 treatment. Treatment with M3 attenuated serum, cardiac, and pulmonary levels of pro-inflammatory cytokines compared to vehicle-treated septic neonates. M3 dramatically increased sepsis survival.

Conclusions

Inhibition of eCIRP/TREM-1 interaction with M3 is cardioprotective, decreases inflammation, and improves survival in neonatal sepsis.

Trial registration Retrospectively registered.

Ursolic acid protects chondrocytes, exhibits anti-inflammatory properties via regulation of the NF-κB/NLRP3 inflammasome pathway and ameliorates osteoarthritis

Inflammation and poor viability of chondrocytes result in the degradation of cartilage as osteoarthritis (OA) progresses. The purpose of the present study was to investigate whether ursolic acid (UA) can protect chondrocytes and alleviate OA. Following stimulation with tumor necrosis factor-α (TNF-α), 5 μM UA displayed no cytotoxicity and reversed the up-regulation of the inflammatory factors MMP13, IL-1β, IL-6 and PTGS2, and down-regulation of the cartilaginous genes/proteins type II collagen and Aggrecan. RNA sequencing identified 533 common deferentially expressed genes (DEGs) of which TNF, PI3K-AKT, NOD-like receptor, cytokine receptor interaction and NF-κB pathways were of potential importance. Further notable DEGs in the most-highly expressed 10 pathways contributed to maintenance of cartilaginous ECM homeostasis and were involved in an inflammatory response. The expression of these most-enriched DEGs was reversed by UA following stimulation with TNF-α. Additional investigation demonstrated that treatment with UA inhibited TNF-α-induced nuclear translocation of p65 and phosphorylation of IκBα and AKT, and reversed TNF-α-induced up-regulation of P20, ACS and NLRP3. Furthermore, rat anterior cruciate ligament transection (ACLT) induced-OA was ameliorated by treatment with UA. In conclusion, these results suggest that UA activates chondrocytes through the NF-κB/NLRP3 inflammasome pathway, thus preventing cartilage degeneration in osteoarthritis.

Soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in neonatal sepsis

BACKGROUND

Efficient and accurate diagnosis of neonatal sepsis is challenging. The potential impact for a reduction in morbidity and mortality as well as antibiotic usage has stimulated the ongoing search for biomarkers of early sepsis. The objective of this pilot study was to quantify the levels of sTREM-1 and correlate with blood cultures and inflammatory markers in neonates evaluated for sepsis.

METHODS

Neonates with suspected sepsis were enrolled (n = 83; Preterm n = 35; Term n = 48). Routine bloods for sepsis evaluation were included and plasma sTREM-1 levels were quantified by ELISA.

RESULTS

Term and preterm neonates (n = 83; Preterm n = 35; Term n = 48) were enrolled and 16 neonates had positive blood cultures (preterm n = 15; term n = 1). sTREM-1 levels were not significantly different in infants with culture-positive or culture-negative sepsis (356 ± 218 pg/mL and 385 ± 254 pg/mL respectively). The immature-to-total granulocyte (I/T) ratio showed a significant positive correlation with sTREM-1 in the preterm group with positive blood cultures. Additionally, sTREM-1 showed a positive correlation with CRP in the preterm group with negative blood cultures.

CONCLUSIONS

sTREM-1 was associated with traditional markers of inflammation (I/T ratio and CRP). However, in this cohort sTREM-1 did not improve the early detection of neonatal culture-positive sepsis.

The role of the triggering receptor expressed on myeloid cells-1 (TREM-1) in non-bacterial infections

The triggering receptor expressed on myeloid cells 1 (TREM-1) is a receptor of the innate immune system, expressed mostly by myeloid cells and primarily associated with pro- inflammatory responses. Although the exact nature of its ligands has not yet been fully elucidated, many microorganisms or danger signals have been proposed as inducers of its activation or the secretion of sTREM-1, the soluble form with putative anti-inflammatory effects. In the course of the 20 years since its first description, several studies have investigated the involvement of TREM-1 in bacterial infections. However, the number of studies describing the role of TREM-1 in fungal, viral and parasite-associated infections has only increased in the last few years, showing a diverse contribution of the receptor in these scenarios, with beneficial or detrimental activities depending on the context. Therefore, this review aims to discuss how TREM-1 may influence viral, fungal and parasitic infection outcomes, highlighting its potential as a therapeutic target and biomarker for diagnosis and prognosis of non-bacterial infectious diseases.

Rheumatoid arthritis synovial fibroblasts promote TREM-1 expression in monocytes via COX-2/PGE2 pathway

BACKGROUND

Triggering receptor expressed on myeloid cells-1 (TREM-1) is inducible on monocyte/macrophages and neutrophils and amplifies the inflammatory response. The aim of this study was to determine whether rheumatoid arthritis synovial fibroblasts (RASF) promote the expression of TREM-1 in monocytes and its potential regulatory mechanism.

METHODS

Synovial fluid and paired peripheral blood from rheumatoid arthritis (RA) patients were analyzed using flow cytometry. Expression of TREM-1 in monocytes was detected after co-culture with RASF, with or without pre-treatment with toll-like receptor (TLR) ligands. Whether RASF-regulated TREM-1 level in monocytes require direct cell contact or soluble factors was evaluated by transwell experiment. COX-2 expression and PGE₂ secretion in RASF were determined by quantitative PCR (qPCR) and ELISA. RASF, with and without TLR ligand stimulation, were treated with COX-2 inhibitors, COX-2 siRNA (siCOX-2) or EP1-4 antagonists, and the resulting TREM-1 level in CD14⁺ monocytes was measured using flow cytometry.

RESULTS

TREM-1 was highly expressed in CD14⁺ cells from peripheral blood and especially synovial fluid from RA patients. The expression of TREM-1 in monocytes was increased by co-culture with RASF. TLR-ligand-activated RASF further elevated TREM-1 level. Transwell assay indicated that soluble factors played a key role in RASF-promoted expression of TREM-1 in monocytes. RASF, with or without stimulation by TLR ligands, increased secretion of PGE₂ in a cyclooxygenase (COX)-2-dependent manner. PGE₂ enhanced the increase in TREM-1 level in monocytes. Finally, studies using COX-2 inhibitors, COX-2 siRNA (siCOX-2) and EP1-4 antagonists, showed that RASF promotion of TREM-1 expression in monocytes was mediated by COX-2/PGE₂/EP2,4 signaling.

CONCLUSIONS

Our data is the first report to reveal the critical role of RASF in upregulating TREM-1 expression in monocytes, which indicates that TREM-1 might be a novel target for RA therapy.

Metalloproteinases TACE and MMP-9 Differentially Regulate Death Factors on Adult and Neonatal Monocytes After Infection with Escherichia coli

Background: Cleaving ligands and receptors of the tumor necrosis factor (TNF) superfamily can critically regulate the induction of apoptosis. Matrix metalloproteinases (MMPs) such as MMP-9 and tumor necrosis factor-α-converting enzyme (TACE) have been shown to cleave CD95-Ligand (CD95L) and TNF/(TNF receptor-1) TNFR1 which induce phagocytosis induced cell death (PICD) in adult monocytes. This process is reduced in neonatal monocytes. Methods: Here we tested in vitro, whether Escherichia coli infection mounts for activation of MMP-9 and TACE in monocytes and whether this process regulates PICD. Results: The surface expression of TACE was most prominent on infected adult monocytes. In contrast, surface presentation of MMP-9 was highest on infected neonatal monocytes. Selective blocking of MMP-9 decreased CD95L secretion, while inhibition of TACE left CD95L secretion unaltered. Blocking of MMP-9 increased surface CD95L (memCD95L) expression on infected neonatal monocytes to levels comparable to infected adult monocytes. Moreover, MMP-9 inhibition raised PICD of infected neonatal monocytes to levels observed for infected adult monocytes. In contrast, TACE inhibition decreased PICD in infected monocytes. Addition of extracellular TNF effectively induced memCD95L presentation and PICD of adult monocytes and less of neonatal monocytes. Conclusion: MMP-9 activity is crucial for downregulating cell-contact dependent PICD in E. coli infected neonatal monocytes. By this mechanism, MMP-9 could contribute to reducing sustained inflammation in neonates.

Expression level of 12-amino acid triggering receptor on myeloid cells-like transcript 1 derived peptide alleviates lipopolysaccharide-induced acute lung injury in mice

Acute lung injury (ALI) is a critical illness with a high morbidity and mortality rate due to severe inflammation in the lungs. The effects and underlying mechanism of the triggering receptor expressed on myeloid cells‑1 (TREM‑1)‑like transcript‑1‑derived peptide (LR12) on ALI remain unclear. The aim of the present study was to determine whether LR12 attenuates lipopolysaccharide (LPS)‑induced ALI and elucidate the mechanism underlying it. Male C57BL/6 mice were randomly assigned to three groups as follows: Sham group, LPS + scramble group and LPS + LR12 group. Normal saline (NS) or LPS was administrated by intratracheal instillation, and NS, LR12 or LR12 scramble was administered intraperitoneally 30 min later. The treatment was repeated every 3 h three times. Mice were sacrificed 24 h later. Pulmonary pathological changes, the lung wet/dry weight ratio, the macrophage and neutrophil counts in bronchoalveolar lavage fluid and myeloperoxidase (MPO) activity in the lung tissues were observed. The inflammatory cytokines were evaluated by enzyme‑linked immunosorbent assay and lung neutrophil infiltration was detected by immunohistochemistry. Nuclear factor (NF)‑κB p65 and TREM‑1 were analyzed by western blotting, and the activation of NF‑κB was detected by electrophoretic mobility shift assay. LPS‑induced pathohistological injury, edema and neutrophil infiltration were significantly alleviated by TREM‑1 inhibitor, LR12. The proinflammatory cytokines [interleukin (IL)‑6, IL‑1β, tumor necrosis factor‑α] and chemokines (keratinocyte chemokine and monocyte chemoattractant protein‑1) were significantly reduced, whereas the anti‑inflammatory cytokines, IL‑10 were significantly increased by LR12. LR12 was identified to significantly decrease p65 expression levels in the nucleus and inhibit the activity of NF‑κB. Furthermore, LR12 alleviated LPS‑induced ALI by reducing the expression of TREM‑1, increasing the release of soluble TREM‑1 and inhibiting activation of the NF-κB signaling pathway.

Functional dissection of astrocyte-secreted proteins: Implications in brain health and diseases

Astrocytes, which are homeostatic cells of the central nervous system (CNS), display remarkable heterogeneity in their morphology and function. Besides their physical and metabolic support to neurons, astrocytes modulate the blood-brain barrier, regulate CNS synaptogenesis, guide axon pathfinding, maintain brain homeostasis, affect neuronal development and plasticity, and contribute to diverse neuropathologies via secreted proteins. The identification of astrocytic proteome and secretome profiles has provided new insights into the maintenance of neuronal health and survival, the pathogenesis of brain injury, and neurodegeneration. Recent advances in proteomics research have provided an excellent catalog of astrocyte-secreted proteins. This review categorizes astrocyte-secreted proteins and discusses evidence that astrocytes play a crucial role in neuronal activity and brain function. An in-depth understanding of astrocyte-secreted proteins and their pathways is pivotal for the development of novel strategies for restoring brain homeostasis, limiting brain injury/inflammation, counteracting neurodegeneration, and obtaining functional recovery.

Knowledge-transfer learning for prediction of matrix metalloprotease substrate-cleavage sites

Matrix Metalloproteases (MMPs) are an important family of proteases that play crucial roles in key cellular and disease processes. Therefore, MMPs constitute important targets for drug design, development and delivery. Advanced proteomic technologies have identified type-specific target substrates; however, the complete repertoire of MMP substrates remains uncharacterized. Indeed, computational prediction of substrate-cleavage sites associated with MMPs is a challenging problem. This holds especially true when considering MMPs with few experimentally verified cleavage sites, such as for MMP-2, -3, -7, and -8. To fill this gap, we propose a new knowledge-transfer computational framework which effectively utilizes the hidden shared knowledge from some MMP types to enhance predictions of other, distinct target substrate-cleavage sites. Our computational framework uses support vector machines combined with transfer machine learning and feature selection. To demonstrate the value of the model, we extracted a variety of substrate sequence-derived features and compared the performance of our method using both 5-fold cross-validation and independent tests. The results show that our transfer-learning-based method provides a robust performance, which is at least comparable to traditional feature-selection methods for prediction of MMP-2, -3, -7, -8, -9 and -12 substrate-cleavage sites on independent tests. The results also demonstrate that our proposed computational framework provides a useful alternative for the characterization of sequence-level determinants of MMP-substrate specificity.

Genetic and Pharmacological Inhibition of TREM-1 Limits the Development of Experimental Atherosclerosis

BACKGROUND

Innate immune responses activated through myeloid cells contribute to the initiation, progression, and complications of atherosclerosis in experimental models. However, the critical upstream pathways that link innate immune activation to foam cell formation are still poorly identified.

OBJECTIVES

This study sought to investigate the hypothesis that activation of the triggering receptor expressed on myeloid cells (TREM-1) plays a determinant role in macrophage atherogenic responses.

METHODS

After genetically invalidating Trem-1 in chimeric Ldlr^-/-Trem-1^-/- mice and double knockout ApoE^-/-Trem-1^-/- mice, we pharmacologically inhibited Trem-1 using LR12 peptide.

RESULTS

Ldlr^-/- mice reconstituted with bone marrow deficient for Trem-1 (Trem-1^-/-) showed a strong reduction of atherosclerotic plaque size in both the aortic sinus and the thoracoabdominal aorta, and were less inflammatory compared to plaques of Trem-1^+/+ chimeric mice. Genetic invalidation of Trem-1 led to alteration of monocyte recruitment into atherosclerotic lesions and inhibited toll-like receptor 4 (TLR 4)-initiated proinflammatory macrophage responses. We identified a critical role for Trem-1 in the upregulation of cluster of differentiation 36 (CD36), thereby promoting the formation of inflammatory foam cells. Genetic invalidation of Trem-1 in ApoE^-/-/Trem-1^-/- mice or pharmacological blockade of Trem-1 in ApoE^-/- mice using LR-12 peptide also significantly reduced the development of atherosclerosis throughout the vascular tree, and lessened plaque inflammation. TREM-1 was expressed in human atherosclerotic lesions, mainly in lipid-rich areas with significantly higher levels of expression in atheromatous than in fibrous plaques.

CONCLUSIONS

We identified TREM-1 as a major upstream proatherogenic receptor. We propose that TREM-1 activation orchestrates monocyte/macrophage proinflammatory responses and foam cell formation through coordinated and combined activation of CD36 and TLR4. Blockade of TREM-1 signaling may constitute an attractive novel and double-hit approach for the treatment of atherosclerosis.

The preterm cervix reveals a transcriptomic signature in the presence of premature prelabor rupture of membranes

BACKGROUND

Premature prelabor rupture of fetal membranes accounts for 30% of all premature births and is associated with detrimental long-term infant outcomes. Premature cervical remodeling, facilitated by matrix metalloproteinases, may trigger rupture at the zone of the fetal membranes overlying the cervix. The similarities and differences underlying cervical remodeling in premature prelabor rupture of fetal membranes and spontaneous preterm labor with intact membranes are unexplored.

OBJECTIVES

We aimed to perform the first transcriptomic assessment of the preterm human cervix to identify differences between premature prelabor rupture of fetal membranes and preterm labor with intact membranes and to compare the enzymatic activities of matrix metalloproteinases-2 and -9 between premature prelabor rupture of fetal membranes and preterm labor with intact membranes.

STUDY DESIGN

Cervical biopsies were collected following preterm labor with intact membranes (n = 6) and premature prelabor rupture of fetal membranes (n = 5). Biopsies were also collected from reference groups at term labor (n = 12) or term not labor (n = 5). The Illumina HT-12 version 4.0 BeadChips microarray was utilized, and a novel network graph approach determined the specificity of changes between premature prelabor rupture of fetal membranes and preterm labor with intact membranes. Quantitative reverse transcription-polymerase chain reaction and Western blotting confirmed the microarray findings. Immunofluorescence was used for localization studies and gelatin zymography to assess matrix metalloproteinase activity.

RESULTS

PML-RARA-regulated adapter molecule 1, FYVE-RhoGEF and PH domain-containing protein 3 and carcinoembryonic antigen-ralated cell adhesion molecule 3 were significantly higher, whereas N-myc downstream regulated gene 2 was lower in the premature prelabor rupture of fetal membranes cervix when compared with the cervix in preterm labor with intact membranes, term labor, and term not labor. PRAM1 and CEACAM3 were localized to immune cells at the cervical stroma and NDRG2 and FGD3 were localized to cervical myofibroblasts. The activity of matrix metalloproteinase-9 was higher (1.22 ± 4.403-fold, P < .05) in the cervix in premature prelabor rupture of fetal membranes compared with preterm labor with intact membranes.

CONCLUSION

We identified 4 novel proteins with a potential role in the regulation of cervical remodeling leading to premature prelabor rupture of fetal membranes. Our findings contribute to the studies dissecting the mechanisms underlying premature prelabor rupture of fetal membranes and inspire further investigations toward the development of premature prelabor rupture of fetal membranes therapeutics.

Effect of TREM-1 blockade and single nucleotide variants in experimental renal injury and kidney transplantation

Renal ischemia reperfusion (IR)-injury induces activation of innate immune response which sustains renal injury and contributes to the development of delayed graft function (DGF). Triggering receptor expressed on myeloid cells-1 (TREM-1) is a pro-inflammatory evolutionary conserved pattern recognition receptor expressed on a variety of innate immune cells. TREM-1 expression increases following acute and chronic renal injury. However, the function of TREM-1 in renal IR is still unclear. Here, we investigated expression and function of TREM-1 in a murine model of renal IR using different TREM-1 inhibitors: LP17, LR12 and TREM-1 fusion protein. In a human study, we analyzed the association of non-synonymous single nucleotide variants in the TREM1 gene in a cohort comprising 1263 matching donors and recipients with post-transplant outcomes, including DGF. Our findings demonstrated that, following murine IR, renal TREM-1 expression increased due to the influx of Trem1 mRNA expressing cells detected by in situ hybridization. However, TREM-1 interventions by means of LP17, LR12 and TREM-1 fusion protein did not ameliorate IR-induced injury. In the human renal transplant cohort, donor and recipient TREM1 gene variant p.Thr25Ser was not associated with DGF, nor with biopsy-proven rejection or death-censored graft failure. We conclude that TREM-1 does not play a major role during experimental renal IR and after kidney transplantation.

In Vivo Anti-Cancer Mechanism of Low-Molecular-Weight Fucosylated Chondroitin Sulfate (LFCS) from Sea Cucumber Cucumaria frondosa

The low-molecular-weight fucosylated chondroitin sulfate (LFCS) was prepared from native fucosylated chondroitin sulfate (FCS), which was extracted and isolated from sea cucumber Cucumaria frondosa, and the anti-cancer mechanism of LFCS on mouse Lewis lung carcinoma (LLC) was investigated. The results showed that LFCS remarkably inhibited LLC growth and metastasis in a dose-dependent manner. LFCS induced cell cycle arrest by increasing p53/p21 expression and apoptosis through activation of caspase-3 activity in LLC cells. Meanwhile, LFCS suppressed the expression of vascular endothelial growth factor (VEGF), increased the expression of tissue inhibitor of metalloproteinase-1 (TIMP-1) and downregulated the matrix metalloproteinases (MMPs) level. Furthermore, LFCS significantly suppressed the activation of ERK1/2/p38 MAPK/NF-κB pathway, which played a prime role in expression of MMPs. All of these data indicate LFCS may be used as anti-cancer drug candidates and deserve further study.

Expression of NF-κB, MCP-1 and MMP-9 in a Cerebral Aneurysm Rabbit Model

Objective:

We explored the early expression of NF-κB, MCP-1 and -MMP 9 in a rabbit carotid aneurysm model, and investigated the possible mechanism of aneurysm.

Methods:

twenty four adult new Zealand rabbits were divided into four groups. normal control (group a); rabbits received elastase induction for 1, 2 3 weeks (group b, C and d respectively); hematoxylin-eosin stains were performed for observation. the mrna and protein expression of NF-κB, MCP-1 and MMP-9 were analyzed using RT-PCR and immunohistochemical methods.

Results:

the expression of NF-κB and MCp-1 reached their peaks after induction for one week, then decreased. their expression in week 1 and week 2 had no statistical difference. the expression of MMP-9 increased after induction. We observed the highest expression at week 3. as the induction time increased, the number of smooth muscles reduced. endothelial cells were damaged; the aneurysm wall elastic layer was damaged.

Conclusion:

activation of NF-κB may be one of the initiating factors contributing to the occurrence and development of cerebral aneurysm. MCP-1 induced macrophage adhesion and infiltration in the artery wall of cerebral aneurysms, and contributed to the occurrence and development of brain aneurysm. damage to elastic fibers is one of the key factors for aneurysm formation. increased infiltration of inflammatory cells and the secretion of MMP-9 are the main reasons for elastic fiber damage.

Distinct signaling cascades of TREM-1, TLR and NLR in neutrophils and monocytic cells

Triggering receptor expressed on myeloid cells 1 (TREM-1) is an important mediator of innate inflammatory responses in microbial infections and sepsis. TREM-1 ligation on neutrophils (PMN) or monocytes results in the production of proinflammatory cytokines. Engagement of TREM-1 induces the activation of MAP kinases as well as rapid Ca(2+) mobilization. However, a detailed understanding of TREM-1 signaling pathways is currently lacking. We evaluated the TREM-1 signaling hierarchy in monocytic cells and found that the acute myeloid leukemia cell line MUTZ-3 expresses TREM-1 in a natural and functional manner. We compared essential signaling molecules of the TREM-1, TLR and NLR cascade in MUTZ-3 cells as well as primary monocytes or PMN by Western blot analysis. These studies confirmed the essential role of phosphatidyl inositide 3-kinase (PI3K) and p38MAPK in the TREM-1 as well as the TLR or NLR cascade of monocytic cells. Importantly, PI3K and p38MAPK signals in monocytic cells both control Ca(2+) mobilization and are directly connected in the TREM-1 signaling hierarchy, which contrasts previous results obtained in PMN. Taken together, our results indicate cell type-specific differences in the TREM-1 signaling cascade and contribute to an enhanced understanding of the regulation of innate inflammatory responses.

Pathophysiology of endotoxin tolerance: mechanisms and clinical consequences

Endotoxin tolerance was first described in a study that exposed animals to a sublethal dose of bacterial endotoxin. The animals subsequently survived a lethal injection of endotoxin. This refractory state is associated with the innate immune system and, in particular, with monocytes and macrophages, which act as the main participants. Several mechanisms are involved in the control of endotoxin tolerance; however, a full understanding of this phenomenon remains elusive. A number of recent reports indicate that clinical examples of endotoxin tolerance include not only sepsis but also diseases such as cystic fibrosis and acute coronary syndrome. In these pathologies, the risk of new infections correlates with a refractory state. This review integrates the molecular basis and clinical implications of endotoxin tolerance in various pathologies.

Characterizing the Genetic Basis for Nicotine Induced Cancer Development: A Transcriptome Sequencing Study

Nicotine is a known risk factor for cancer development and has been shown to alter gene expression in cells and tissue upon exposure. We used Illumina® Next Generation Sequencing (NGS) technology to gain unbiased biological insight into the transcriptome of normal epithelial cells (MCF-10A) to nicotine exposure. We generated expression data from 54,699 transcripts using triplicates of control and nicotine stressed cells. As a result, we identified 138 differentially expressed transcripts, including 39 uncharacterized genes. Additionally, 173 transcripts that are primarily associated with DNA replication, recombination, and repair showed evidence for alternative splicing. We discovered the greatest nicotine stress response by HPCAL4 (up-regulated by 4.71 fold) and NPAS3 (down-regulated by -2.73 fold); both are genes that have not been previously implicated in nicotine exposure but are linked to cancer. We also discovered significant down-regulation (-2.3 fold) and alternative splicing of NEAT1 (lncRNA) that may have an important, yet undiscovered regulatory role. Gene ontology analysis revealed nicotine exposure influenced genes involved in cellular and metabolic processes. This study reveals previously unknown consequences of nicotine stress on the transcriptome of normal breast epithelial cells and provides insight into the underlying biological influence of nicotine on normal cells, marking the foundation for future studies.

Holothurian glycosaminoglycan inhibits metastasis and thrombosis via targeting of nuclear factor-κB/tissue factor/Factor Xa pathway in melanoma B16F10 cells

Holothurian glycosaminoglycan (hGAG) is a high-molecular-weight form of fucosylated chondroitin sulfate and has an antithrombotic effect. Our previous studies demonstrated that hGAG efficiently inhibited tumor cell metastasis. The interplays between thrombosis and tumor progression may have a major impact on hematogenous metastasis. In this study, we demonstrated that the mouse melanoma B16F10 cells treated with hGAG displayed a significant reduction of metastasis and coagulation capacity in vitro and in vivo. Mechanistic studies revealed that hGAG treatment in B16F10 cells remarkably inhibited the formation of fibrin through attenuating the generation of activated Factor Xa (FXa), without affecting the expression of urokinase (uPA) and plasminogen activator inhibitor 1 (PAI-1) that involved in fibrinolysis. Moreover, hGAG treatment downregulated the transcription and protein expression of tissue factor (TF). Promoter deletions, site mutations and functional studies identified that the nuclear transcription factor NF-κB binding region is responsible for hGAG-induced inhibition of TF expression. While the hGAG treatment of B16F10 cells was unable to inhibit NF-κB expression and phosphorylation, hGAG significantly prevented nuclear translocation of NF-κB from the cytosol, a potential mechanism underlying the transcriptional suppression of TF. Moreover, hGAG markedly suppressed the activation of p38MAPK and ERK1/2 signaling pathways, the central regulators for the expression of metastasis-related matrix metalloproteinases (MMPs). Consequently, hGAG exerts a dual function in the inhibition of metastasis and coagulation activity in mouse melanoma B16F10 cells. Our studies suggest hGAG to be a promising therapeutic agent for metastatic cancer treatment.

The importance of biomarkers in neonatology

Despite a 35% decline in the mortality rate for infants aged <5 years over the past two decades, every year nearly 40% of all deaths in this age group occur in the neonatal period, defined as the first 28 days of life. New knowledge on molecular and biochemical pathways in neonatal diseases will lead to the discovery of new candidate biomarkers potentially useful in clinical practice. In the era of personalized medicine, biomarkers may play a strategic role in accelerating the decline in neonatal mortality by assessing the risk of developing neonatal diseases, by implementing tailored therapeutic treatment, and by predicting the clinical outcome. However, there is an urgent need to reduce the gap in translating newly acquired knowledge from bench to bedside. Traditional and candidate biomarkers for neonatal sepsis and necrotizing enterocolitis will be discussed in this review, such as C-reactive protein (CRP), procalcitonin (PCT), serum amyloid A (SAA), soluble form of CD14 subtype presepsin (sCD14-ST), lipolysaccharide binding protein (LBP), angiopoietins (Ang)-1 and -2, soluble form of triggering receptor expressed on myeloid cells (sTREM-1), soluble form of urokinase-type plasminogen activator receptor (suPAR), platelet-activating factor (PAF) and calprotectin. New frontiers in managing critically ill newborns may be opened by metabolomics, a diagnostic tool based on the recognition of metabolites contained in biological fluids. Metabolomics represents the passage from a descriptive science to a predictive science, having the potential to translate benchtop research to real clinical benefits.

Modulation of cytokine release and gene expression by the immunosuppressive domain of gp41 of HIV-1

The transmembrane envelope protein gp41 of the human immunodeficiency virus HIV-1 plays an important role during infection allowing fusion of the viral and cellular membrane. In addition, there is increasing evidence that gp41 may contribute to the immunodeficiency induced by HIV-1. Recombinant gp41 and a synthetic peptide corresponding to a highly conserved domain in gp41, the immunosuppressive (isu) domain, have been shown to inhibit mitogen-induced activation of human peripheral blood mononuclear cells (PBMCs) and to increase release of IL-6 and IL-10 from these cells. We recently reported that a single mutation in the isu domain of gp41 abrogated the immunosuppressive properties and that HIV-1 sequences containing such abrogating mutations had never been isolated from infected individuals. Here, we studied the influence of the isu peptide on the release of 66 cytokines and the expression of 27,000 genes in PBMCs. Incubation of PBMCs with isu peptide homopolymers increased the expression of 16 cytokines among them IL-6 and IL-10, and decreased that of IL-2 and CXCL9. Interestingly, the extend of cytokine modulation was donor-dependent. Among the genes up-regulated were IL-6, IL-8, IL-10 but also MMP-1, TREM-1 and IL-1beta. Most importantly, genes involved in innate immunity such as FCN1 and SEPP1 were found down-regulated. Many changes in cytokine expression demonstrated in our experiments were also found in HIV-1 infected individuals. These data indicate that the isu domain of gp41 has a broad impact on gene expression and cytokine release and therefore may be involved in HIV-1 induced immunopathogenesis.