The role of neuroplastin65 in macrophage against E. coli infection in mice.

BACKGROUND: Innate immune response constitutes the first line of defense against pathogens. Inflammatory responses involve close contact between different populations of cells. These adhesive interactions mediate migration of cells to sites of infection leading the effective action of cells within the lesions. Cell adhesion molecules are critical to controlling immune response mediating cell adhesion or chemotaxis, as well as coordinating actin-based cell motility during phagocytosis and chemotaxis. Recently, a newly discovered neuroplastin (Np) adhesion molecule is found to play an important role in the nervous system. However, there is limited information on Np functions in immune response. To understand how Np is involved in innate immune response, a mouse model of intraperitoneal infection was established to investigate the effect of Np on macrophage-mediated clearance of E. coli infection and its possible molecular mechanisms. METHODS: Specific deficiency mice with Nptn gene controlling Np65 isoform were employed in this study. The expression levels of mRNA and proteins were detected by qPCR and western blot, or evaluated by flow cytometry. The expression level of NO and ROS were measured with their specific indicators. Cell cycle and apoptosis were detected by specific detection kits. Acid phosphatase activity was measured by flow cytometry after labelling with LysoRed fluorescent probe. Bone marrow derived macrophages (BMDMs) were isolated from bone marrow of mice hind legs. Cell proliferation was detected by CCK8 assay. Cell migration was measured by wound healing assay or transwell assay. RESULTS: The lethal dose of E. coli infection in Np65-/- mice dropped to the half of lethal dose in WT mice. The bacterial load in the spleen, kidney and liver from Np65-/- mice were significantly higher than that from WT mice, which were due to the dramatic reduction of NO and ROS production in phagocytes from Np65-/- mice. Np65 gene deficiency remarkably impaired phagocytosis and function of lysosome in macrophage. Furthermore, Np65 molecule was involved in maturation and proliferation, even in migration and chemotaxis of BMDM in vitro. CONCLUSION: This study for the first time demonstrates that Np is involved in multi-function of phagocytes during bacterial infection, proposing that Np adhesion molecule plays a critical role in clearing pathogen infection in innate immunity.

The Dynamic Interactions between Nanoparticles and Macrophages Impact Their Fate in Brain Tumors.

Functional nanomaterials such as iron oxide nanoparticles have been extensively explored for the diagnosis and treatment of central nervous system diseases. However, an insufficient understanding of the comprehensive nanomaterial-biological interactions in the brain hinders the nanomaterials from meeting the medical requirements for translational research. Here, FDA-approved ferumoxytol, an iron oxide nanoparticle, is chosen as the model nanomaterial for a systematic study of the dynamic interactions between ferumoxytol and immune cells, including microglia and macrophages, in the brain tumors. Strikingly, up to 90% of intratumorally injected ferumoxytol nanoparticles are recognized and phagocytized by tumor-associated microglia and macrophages. The dynamic trafficking progress of ferumoxytol in microglia and macrophages, including scavenger receptor-mediated endocytosis, lysosomal internalization, and extracellular vesicle-dominated excretion, is further studied. Importantly, the results demonstrate that extracellular vesicle-encapsulated nanoparticles could be gradually eliminated from the brain along with cerebrospinal fluid circulation over 21 days. Moreover, ferumoxytol exhibits no obvious long-term neurological toxicity after its injection. The study suggests that the dynamic biointeractions of nanoparticles with immune cells in the brain exert a key rate-limiting impact on the efficiency of targeting tumor cells and their in vivo fate and thus provide a deeper understanding of the nanomaterials in the brain for clinical applications.

Metal-Phenolic Network Covering on Zein Nanoparticles as a Regulator on the Oil/Water Interface.

Interfacial self-assembly has become a powerful force for regulating the amphipathy of Pickering emulsions on the oil/water interface. Herein, metal-phenolic supramolecular coatings, acting as a regulator on the oil/water interface, were fabricated on the surface of zein nanoparticles (NPs), as a consequence of which the prepared Pickering emulsions stabilized by the decorated zein NPs exhibited diverse properties, decided by different concentrations of zein, tannic acid (TA), and metal ions (Fe3+). Metal-phenolic network-decorated zein NPs named ZTFex NPs (ZTFe NPs represented zein/TA/Fe3+ NPs, and x represented different concentrations of compounds) exhibited increasing diameters of 100-110 nm. Three-phase contact angles also showed that the strong hydrophobicity of zein NPs could be decreased as a result of the formation of metal-phenolic networks. As for corresponding Pickering emulsions, the covering of TA-Fe3+ networks on zein NPs could enhance the stability of zein NP-based emulsion obviously, which might be due to the fact that ZTFex NPs revealed the ability to form strong films on the oil/water interfaces. ZTFe4 was selected as an optimal concentration because of its minimum size and excellent storage stability. Besides, it was also found that the diameter of ZTFe4-based emulsion enhanced with the increase in the oil phase. The rheological measurement results showed that both G' and G″ increased with the increase of x and the oil phase. In general, our paper not only highlighted a straightforward method for the interfacial nanofabrication of solid particles but also provided a novel and potential strategy in Pickering emulsion applications.

Diatomological mapping of water bodies in Chongqing section of the Yangtze River and Jialing River.

The diagnosis of drowning is one of the most difficult in forensic medicine. Forensic diatomology has been proposed to be useful in solving the diagnosis of drowning and considered to be a reliable indicator of the site of drowning. The Yangtze River and Jialing River are the main rivers in the Chongqing area (China), and a large number of corpses are found in the rivers every year. However, the distribution of diatoms in the rivers was not fully studied. In the presented study, a Microwave Digestion-Vacuum Filtration-Scanning Electron Microscopy (MD-VF-SEM) method was performed to acquire the qualitative and quantitative data of diatoms of water samples collected from 10 different sites of the Yangtze River and Jialing River in Chongqing section during different seasons. Our study not only created the diatomological maps of water bodies in Chongqing section of the Yangtze River and Jialing River for the first time but also identified some seasonal and site-specific diatoms that can be taken as markers of particular sites or seasons of drowning. The results of our study may provide forensic scientists helpful reference in solving the drowning cases.

Early secreted antigenic target of 6-kDa of Mycobacterium tuberculosis induces transition of macrophages into epithelioid macrophages by downregulating iNOS / NO-mediated H3K27 trimethylation in macrophages.

BACKGROUND: Tuberculosis (TB) is a chronic infectious disease caused by Mycobacterium tuberculosis (Mtb). Granuloma is a pathological feature of tuberculosis and is a tight immune cell aggregation caused by Mtb. The main constituent cells are macrophages and their derivative cells including epithelioid macrophages. However, the molecular mechanism of the transition has not been reported. The purpose of this study was to investigate whether early secreted antigenic target of 6-kDa (ESAT6) can induce the transition of bone marrow-derived macrophages (BMDMs) into epithelioid macrophages and its possible molecular mechanism. METHODS: The recombinant ESAT6 protein was obtained from E.coli carrying esat6 gene after isopropyl ß-d-thiogalactopyranoside (IPTG) induction. BMDMs were isolated from bone marrow of mice hind legs. Cells viability was detected by Cell Counting Kit 8 (CCK8) assays. The expression levels of mRNA and proteins were detected by qPCR and Western blot, or evaluated by flow cytometry. The expression level of nitric oxide (NO) was measured with a nitric oxide indicator. RESULTS: ESAT6 could significantly induce mRNA and protein expression levels of a group of epithelioid macrophages marker molecules (EMMMs), including E-cadherin, junction plakoglobin, ZO1, desmoplakin, desmoglein3 and catenin porteins, in BMDMs. These events could be abrogated in macrophage from TLR2 deficiency mice. ESAT6 could also markedly induce iNOS/NO production that could significantly inhibit trimethylation of H3K27 in the cells. ESAT6-induced expressions of epithelioid macrophages marker molecules were significantly inhibited in the presence of H3K27 histone demethylase inhibitor GSK J1. Furthermore, ROS scavenging agent N,N'-Dimethylthiourea (DMTU) could markedly inhibit the transition induced by ESAT6 in macrophages. CONCLUSION: This study demonstrates that ESAT6 bound with TLR2 can activate iNOS/NO and ROS signalings to reduce the trimethylation of H3K27 resulting in the increment of EMMMs expression that is beneficial to the transition of macrophages into epithelioid macrophages. However, hypoxia can inhibit this transition event. This study has provided new evidence of pathogenesis of granuloma caused by Mtb and also proposed new ideas for the treatment of TB.

UPLC-Q-TOF/MS Based Metabolomics Approach to Study the Hepatotoxicity of Cantharidin on Mice.

Cantharidin is the major bioactive compound extracted from the blister beetle, a traditional Chinese medicine, and has been proved to be a natural component with widely antitumor activity. However, clinical application of cantharidin is relatively restricted due to its potential toxic effects, especially hepatotoxicity. Although cantharidin-induced liver injury has been reported, the underlying molecular mechanisms remain unclear. In the present study, an UPLC-Q-TOF/MS based metabolomics approach combined with blood biochemical analysis, histopathological examination, and cell apoptosis assay were used to investigate the mechanisms of cantharidin-induced hepatotoxicity. A total of 54 significantly changed metabolites and 14 disturbed metabolic pathways were identified in the cantharidin exposed groups. Among them, four metabolites (oxidized glutathione, glutathione, 3-sulfinoalanine, and deoxycholic acid 3-glucuronide) were selected based on their high impact value and potential biological function in the process of liver injury post cantharidin treatment. Our study provides a deeper understanding of the mechanisms of cantharidin-induced hepatotoxicity and may contribute to reduce the liver injury and gain more effective and safe clinical use of cantharidin. In addition, our results also demonstrated that cantharidin could impair multiple biological processes in liver, and future studies will be necessary to reveal the detailed molecular mechanisms of cantharidin-induced hepatotoxicity.

Early secreted antigenic target of 6-kDa of Mycobacterium tuberculosis promotes caspase-9/caspase-3-mediated apoptosis in macrophages.

Mycobacterium tuberculosis (Mtb) is an intracellular pathogen that triggers several survival mechanisms against the host immune system. Many studies show that the diverse components of Mtb can modulate apoptosis in various types of cells differently. So far, apoptosis induced by ESAT-6, an early secreted antigenic target of 6-kDa of Mtb, has been studied but the details of molecular mechanism and signaling pathway remain incompletely defined. This study investigated the role of recombinant ESAT-6 in inducing apoptosis in primary bone marrow-derived macrophages (BMDMs) of mice using Annexin V/PI assay with FACS analysis and Western blotting technique. It has been found that ESAT-6-induced apoptosis in BMDMs in a dose- and time-dependent pattern. Apoptosis induced by ESAT-6 was mainly via the intrinsic pathway with elevated protein levels of cleaved caspase-9 and -3. Furthermore, ESAT-6 also induced Bim activation during this process. Interestingly, this event was TLR2-dependent since the effect of ESAT-6 on apoptosis vanished in BMDM from mice with TLR2 deficiency. Furthermore, ROS generation and MAPKs phosphorylation induced by ESAT-6 were also involved in caspase-9 and caspase-3 activation. Taken together, these data suggest that ESAT-6-mediated apoptosis is involved in ROS-MAPKs signaling and further activating the intrinsic pathway, which provides new insights into the basic physiology of macrophage death in tuberculosis.

Integration of 1H NMR- and UPLC-Q-TOF/MS-based plasma metabonomics study to identify diffuse axonal injury biomarkers in rat.

Diffuse axonal injury (DAI) is much common during traumatic brain injury (TBI) and is associated with high mortality and poor neurological outcome. Although many studies have been examined, there are still no reliable objective diagnostic modalities available for clinicians to make an early diagnosis of DAI. Therefore, we established a rat model of DAI, applying an integrated 1H NMR- and UPLC-Q-TOF/MS-based metabonomics approach to identify differentially changed metabolites in plasma. A total of twenty-two metabolites in the injury group were identified as differentially changed. Among them, four metabolites, glutamine, pyruvate, glycerol and phosphocholine, were identified as candidate biomarkers based on their high fold-changes and biological functions, and may play important roles in axonal injury progression in DAI. Our study not only identified several novel biomarkers that improved our understanding of the metabolic events underlying DAI, but also may provide some potential novel therapeutic targets for preventing axonal injury in DAI.

iTRAQ-based differential proteomic analysis of the brains in a rat model of delayedcarbon monoxide encephalopathy.

Delayed encephalopathy after acute carbon monoxide poisoning (DEACMP) is a difficult-to-manage neurological complication that can severely affect the life quality of patients. Although the central nervous system (CNS) injuries have been reported, the underlying molecular mechanisms are still unclear. Therefore, we established a rat model of DEACMP, applying isobaric tags for a relative and absolute quantification (iTRAQ)-based proteomics approach to identify differentially expressed proteins in cerebral tissue. A total of 170 proteins in the CO exposure groups were identified as differentially changed. Bioinformatics analysis suggested that these proteins are mainly involved in the biological processes, such as energy metabolism and many neurodegenerative diseases. Three proteins, Glial fibrillary acidic protein (GFAP), mitochondrial malate dehydrogenase (MDHM), and isocitrate dehydrogenase [NAD] subunit alpha (IDH3A), were identified as playing important roles in CNS injuries in DEACMP, and were successfully confirmed by immunohistochemistry analysis. Our study not only offers us new insights into the pathophysiological mechanisms of CNS injuries in DEACMP, but also may provide clinicians with important references in early prevention and treatment.

Vascular endothelial cells senescence is associated with NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome activation via reactive oxygen species (ROS)/thioredoxin-interacting protein (TXNIP) pathway.

Endothelial dysfunction caused by endothelial cells senescence and chronic inflammation is tightly linked to the development of cardiovascular diseases. NLRP3 (NOD-like receptor family pyrin domain-containing3) inflammasome plays a central role in inflammatory response that is associated with diverse inflammatory diseases. This study explores the effects and possible mechanisms of NLRP3 inflammasome in endothelial cells senescence. Results show an increment of pro-inflammatory cytokine interleukin (IL) -1ß secretion and caspase-1 activation during the senescence of endothelial cells induced by bleomycin. Moreover, secreted IL-1ß promoted endothelial cells senescence through up-regulation of p53/p21 protein expression. NLRP3 inflammasome was found to mediate IL-1ß secretion through the production of ROS (reactive oxygen species) during the senescence of endothelial cells. Furthermore, the association of TXNIP (thioredoxin-interacting protein) with NLRP3 induced by ROS promoted NLRP3 inflammasome activation in senescent endothelial cells. In addition, the expressions of NLRP3 inflammasome related genes, ASC (apoptosis associated speck-like protein containing a CARD), TXNIP, cleaved caspase-1 and IL-1ß, were also increased in vitro and in vivo studies. These findings indicate that endothelial senescence could be mediated through ROS and NLRP3 inflammasome signaling pathways, suggesting a potential target for the prevention of endothelial senescence-related cardiovascular diseases.

Downregulation of B-myb promotes senescence via the ROS-mediated p53/p21 pathway, in vascular endothelial cells.

OBJECTIVES: To reveal whether B-myb is involved in preventing senescence of vascular endothelial cells, and if so, to identify possible mechanisms for it. MATERIALS AND METHODS: C57/BL6 male mice and primary human aortic endothelial cells (HAECs) were used. Bleomycin was applied to induce stress-related premature senescence. B-myb knockdown was achieved using an siRNA technique and cell senescence was assessed using the senescence-associated ß-galactosidase (SA-ß-gal) assay. Intracellular reactive oxygen species (ROS) production was analysed using an ROS assay kit and cell proliferation was evaluated using KFluor488 EdU kit. Capillary tube network formation was determined by Matrigel assay. Expressions of mRNA and protein levels were detected by real-time PCR and western blotting. RESULTS: B-myb expression significantly decreased, while p53 and p21 expressions increased in the aortas of aged mice. This expression pattern was also found in replicative senescent HAECs and senescent HAECs induced by bleomycin. B-myb knockdown resulted in upregulation of p22phox , ROS accumulation and cell senescence of HAECs. Downregulation of B-myb significantly inhibited cell proliferation and capillary tube network formation and activated the p53/p21 signalling pathway. Blocking ROS production or inhibiting p53 activation remarkably attenuated SA-ß-gal activity and delayed cell senescence induced by B-myb-silencing. CONCLUSION: Downregulation of B-myb induced senescence by upregulation of p22phox and activation of the ROS/p53/p21 pathway, in our vascular endothelial cells, suggesting that B-myb may be a novel candidate for regulating cell senescence to protect against endothelial senescence-related cardiovascular diseases.

Global intron retention mediated gene regulation during CD4+ T cell activation.

T cell activation is a well-established model for studying cellular responses to exogenous stimulation. Using strand-specific RNA-seq, we observed that intron retention is prevalent in polyadenylated transcripts in resting CD4(+) T cells and is significantly reduced upon T cell activation. Several lines of evidence suggest that intron-retained transcripts are less stable than fully spliced transcripts. Strikingly, the decrease in intron retention (IR) levels correlate with the increase in steady-state mRNA levels. Further, the majority of the genes upregulated in activated T cells are accompanied by a significant reduction in IR. Of these 1583 genes, 185 genes are predominantly regulated at the IR level, and highly enriched in the proteasome pathway, which is essential for proper T cell proliferation and cytokine release. These observations were corroborated in both human and mouse CD4(+) T cells. Our study revealed a novel post-transcriptional regulatory mechanism that may potentially contribute to coordinated and/or quick cellular responses to extracellular stimuli such as an acute infection.

SOCS3 and its role in associated diseases.

Cell-cell communication depends on cytokine and growth factor network. Bound to their receptors on the surface of target cell, these glycoproteins initiate a range of intracellular events. Subsequent dissipation of receptor signaling is essential to ensure the response of the cell does not become pathogenic. The Suppressors of cytokine signaling (SOCS) proteins are a family of proteins induced to attenuate cytokine signal transduction in response to signals from a diverse range of cytokines and growth factors. Current evidence indicates that intracellular JAK-STAT (Janus kinase-signal transducer and activator of transcription) signaling not only governs cytokine-induced immunological responses but also rapidly initiates SOCS expression and its biological functions. This review focuses on current understanding of SOCS3, a member of SOCS family. SOCS3 binds to JAK, certain cytokine receptors in intracellular domain, and some signaling molecules, which results in suppressing further signaling events in the cell. Studies using conditional knockout mice have shown that SOCS3 protein is the key physiological regulator and plays an important pathological role in immune homeostasis. Dysregulation of SOCS3 functions can cause a variety of diseases, including allergy, autoimmune diseases, inflammation and cancer.

The involvement of NADPH oxidase-mediated ROS in cytokine secretion from macrophages induced by Mycobacterium tuberculosis ESAT-6.

The 6-kDa early secretory antigenic target (ESAT-6) of Mycobacterium tuberculosis is strongly correlated with subversion of innate immune responses against invading mycobacteria. To understand the role of ESAT-6 in macrophage response against M. tuberculosis, the effects of ESAT-6 on macrophage generation of reactive oxygen species (ROS) and production of cytokines were studied. ESAT-6-induced macrophage secretion of monocyte chemoattractant protein-1 and TNF-α was found in a time- and dose-dependent manner. Signaling inhibition experiments indicate that NF-κB activation mediated by p38/JNK mitogen-activated protein kinase (MAPK) was involved in ESAT-6-triggered cytokine production. Moreover, TLR2 was engaged in ESAT-6-stimulated macrophage activation via rapidly induced ROS production and regulated activation of JNK/p38 MAPKs and NF-κB. More importantly, NADPH oxidase-mediated ROS generation is required during this process. Our study has identified a novel signal transduction pathway involving NADPH-ROS-JNK/p38-NF-κB in ESAT-6-induced cytokine production from macrophages. These findings provide an important evidence to understand the pathogenesis of M. tuberculosis infection in the modulation of the immune response.

OxLDL-induced IL-1 beta secretion promoting foam cells formation was mainly via CD36 mediated ROS production leading to NLRP3 inflammasome activation.

OBJECTIVE: IL-1ß is a master switch of inflammation and plays an important role in the pathogenesis of vascular disease. During early atherosclerosis development, it is not clearly understood how oxidized low density lipoprotein (oxLDL)induced signaling pathways control NLRP3 inflammasome activation and produce IL-1ß and promote foam cells formation. METHODS: The study used THP-1 macrophage as cell model. Western blot quantified the oxLDL-induced NLRP3 inflammasome related proteins. The FACS detected the expression of SR-A and CD36 receptors on the cells, and caspase-1 activation in the cells. The DCFH-DA assayed the reactive oxygen species (ROS). Oil red O staining techniques examined the intracellular lipid droplet. RESULTS: The OxLDL remarkably increased not only IL-1ß mRNA transcription and pro-IL-1ß protein synthesis but also IL-1ß secretion in human macrophages. The activation of the NLRP3 inflammasome depended on oxLDL-induced generation of ROS, potassium efflux and cathepsin B activity. The OxLDL-induced ROS production that mediates IL-1ß maturation mainly depended on the scavenger receptor of CD36 but not SR-A. The secreted IL-1ß served as an autocrine function for promoting macrophage foam cells formation. CONCLUSIONS: These findings suggest that oxLDL-induced NLRP3 inflammasome activation mainly depends on CD36 involved in the progression of atherosclerosis by promoting oxLDL-mediated inflammation and foam cell formation.

The essential role of p38 MAPK in mediating the interplay of oxLDL and IL-10 in regulating endothelial cell apoptosis.

Interleukin-10 (IL-10) may have therapeutic potential in various inflammatory diseases, including atherosclerosis, as it can inhibit oxLDL-induced foam cell formation and apoptosis in macrophages. This study investigated the effect of IL-10 on mitogen-activated protein kinase (MAPK) activation, and apoptosis induced by oxidized low-density lipoprotein (oxLDL) in cultured human umbilical vein endothelial cells (HUVEC). The results demonstrated that IL-10 significantly blocked the phosphorylation of p38 MAPK and c-Jun N-terminal kinase (JNK) and apoptosis induced by oxLDL. The inhibitory effect of IL-10 on oxLDL-induced apoptosis was partially dependent on reduced p38, but not JNK, phosphorylation. This study also discovered a linkage between IL-10 and p38 MAPK signaling in oxLDL-induced endothelial cell apoptosis. Interestingly, this study found that lectin-like oxidized LDL receptor-1 (LOX-1) was the only scavenger receptor, on the surface of HUVEC, that was upregulated by oxLDL and the increase in LOX-1 was not suppressed by IL-10. This study confirmed that IL-10 significantly upregulated the expression of suppressor of cytokine signaling-3 (SOCS3), whereas SOCS3 knockdown by siRNA effectively blocked the inhibitory effect of IL-10 on p38 MAPK-dependent apoptosis induced by oxLDL. These results showed for the first time, that IL-10 modulated oxLDL-induced apoptosis by upregulating SOCS3, which then interrupted p38 MAPK activation in endothelial cells. These findings support the essential role of p38 MAPK in the interplay of oxLDL and IL-10 in endothelial apoptosis.

Modification of SR-PSOX functions by multi-point mutations of basic amino acid residues.

SR-PSOX can function as a scavenger receptor, a chemokine and an adhesion molecule, and it could be an interesting player in the formation of atherosclerotic lesions. Our previous studies demonstrated that basic amino acid residues in the chemokine domain of SR-PSOX are critical for its functions. In this study the combinations of the key basic amino acids in the chemokine domain of SR-PSOX have been identified. Five combinations of basic amino acid residues that may form conformational motif for SR-PSOX functions were selected for multi-point mutants. The double mutants of K61AR62A, R76AK79A, R82AH85A, and treble mutants of R76AR78AK79A, R78AR82AH85A were successfully constructed by replacing the combinations of two or three basic amino acid residues with alanine. After successful expression of these mutants on the cells, the functional studies showed that the cells expressing R76AK79A and R82AH85A mutants significantly increased the activity of oxLDL uptake compared with that of wild-type SR-PSOX. Meanwhile, the cells expressing R76AK79A mutant also dramatically enhanced the phagocytotic activity of SR-PSOX. However, the cells expressing the construct of combination of R78A mutation in R76AK79A or R82AH85A could abolish these effects. More interestingly, the adhesive activities were remarkably down regulated in the cells expressing the multi-point mutants respectively. This study revealed that some conformational motifs of basic amino acid residues, especially R76 with K79 in SR-PSOX, may form a common functional motif for its critical functions. R78 in SR-PSOX has the potential action to stabilize the function of oxLDL uptake and bacterial phagocytosis. The results obtained may provide new insight for the development of drug target of atherosclerosis.

The association of elevated 2',5'-oligoadenylate-dependent RNase L with lung cancer correlated with deficient enzymatic activity and decreased capacity of RNase L dimerization.

RNase L mediates critical cellular functions including antiviral, proapoptotic, antiproliferative and tumor suppressive activities. In this study, the expression and function of RNase L in lung cancer cells were examined. Interestingly we have found that the expression of RNase L in lung cancer cells was 3- and 9-fold higher in its mRNA and protein levels, but a significant decrease of its enzymatic activity when compared to that in corresponding normal lung cells. Further investigation revealed that 2-5A-induced dimerization of the RNase L protein, a necessary prerequisite for activation of RNase L, was inhibited, as a result of that RLI, a specific inhibitor of RNase L, was remarkably up-regulated in the cancer cells. Our findings provide new insight into how cancer cells escape normal growth-regulating mechanisms to form a tumor and the information may be useful for the design of novel strategies for treating lung cancer through regulating RNase L activity.

Lentivirus-mediated short-hairpin RNA targeting IGF-1R inhibits growth and lymphangiogenesis in breast cancer.

In this study, we investigated the effects of lentivirus (LV)-mediated short hairpin RNA (shRNA) targeting IGF-1R on the growth and lymphangiogenesis of breast cancer. The LV vector effectively delivered the IGF-1R shRNA to MDA-MB­231 cells, leading to significant reduction of IGF-1R mRNA and protein expression. Infection of MDA-MB-231 cells with LV-IGF-1R shRNA reduced cell growth and migration. Transplantation of MDA-MB-231 cells with suppressed IGF-1R expression in SCID mice reduced tumor growth and lymphangiogenesis. These data collectively suggest that LV-mediated shRNA is an effective way to suppress IGF-1R expression and to inhibit growth and lymphangiogenesis of breast cancer. Specific inhibition of IGF-1R expression with shRNA represents a promising approach for the treatment of breast cancer.

An essential function for MKP5 in the formation of oxidized low density lipid-induced foam cells.

The uptake of oxidized low density lipoprotein (ox-LDL) by macrophages usually leads to the formation of lipid-laden macrophages known as "foam cells," and this process plays an important role in the development of atherosclerosis. Ox-LDL activates mitogen-activated protein kinase (MAP) kinases and nuclear factor (NF)-κB, and activations of p38 and NF-κB are important for the formation of foam cells. MAP kinase phosphatase (MKP) 5 is a member of the dual specificity phosphatases (DUSPs) family that can selectively dephosphorylate activated MAPKs to regulate innate and adaptive immune responses. However, the role of MKP5 in the formation of foam cells remains unknown. Here, we found that stimulation of ox-LDL induces the expression of MKP5 in macrophages. MKP5 deficiency blocked the uptake of ox-LDL and the formation of foam cells. Further analysis revealed that deletion of MKP5 reduced the ox-LDL-induced activation of NF-κB. Also, MKP5 deficiency markedly inhibited the production of TNF-α, but enhanced the levels of TGF-ß1 in ox-LDL-stimulated macrophages. Moreover, inhibition of NF-κB by p65 RNAi significantly reduced foam cell formation in macrophages from WT mice relative to MKP5-deficient mice. Thus, MKP5 has an essential role in the formation of foam cells through activation of NF-κB, and MKP5 represents a novel target for the therapeutic intervention of atherosclerosis.