circ-ZEB1 regulates epithelial-mesenchymal transition and chemotherapy resistance of colorectal cancer through acting on miR-200c-5p

Circular RNAs (circRNAs) have been demonstrated to be important regulators in human malignant tumors, including colorectal cancer (CRC). While the role circ-ZEB1 played in CRC remains unclear. In this study, we aim to explore the biological function and the underlying mechanism of circ-ZEB1 in CRC. RNAscope was used to analyze the expression and localization of circ-ZEB1 in CRC tissues. Loss of function experiments were conducted, including CCK-8, transwell assays, flow cytometry analysis, and murine xenograft models, so as to detect the effect of circ-ZEB1 on CRC cells. IC50 assay was used to evaluate the influence of circ-ZEB1 on the chemoresistance of CRC cells. Epithelial-mesenchymal transition (EMT) related markers were detected. The relationship between circ-ZEB1 and miR-200c-5p was investigated by FISH, dual-luciferase reporter assay, and RIP assay. We found in our study that circ-ZEB1 was significantly upregulated in CRC tissues. Downregulation of circ-ZEB1 inhibited cell proliferation, colony formation, as well as cell migration and invasion abilities of CRC cell lines. In vivo experiments indicated that knockdown of circ-ZEB1 suppressed tumorigenesis and distant metastasis of CRC cells in nude mice. What's more, EMT and chemoresistance of CRC cells were also attenuated following circ-ZEB1 knockdown. Mechanistically, we proved that circ-ZEB1 could directly bind with miR-200c and functioned as miR-200c sponge to exert its biological functions in CRC cells. In conclusion, circ-ZEB1 could promote CRC cells progression, EMT, and chemoresistance via acting on miR-200c, elucidating a potential therapeutic target to inhibit CRC progression.     

β3-adrenergic receptor induction of adipocyte inflammation requires lipolytic activation of stress kinases p38 and JNK

Activation of β-adrenergic receptors (AR) in adipocytes triggers acute changes in metabolism that can alter patterns of gene expression. This work examined the mechanisms by which activation of hormone sensitive lipase (HSL) induces expression of inflammatory cytokines in adipocytes in vivo and model adipocytes in vitro. β3-AR activation in mice triggered expression of inflammatory genes CCL2, IL-6, and PAI-1, as well as endoplasmic reticulum (ER) stress markers GRP78 and CHOP. Pharmacological inhibition of HSL blocked induction of inflammatory genes, but not ER stress markers. Promoting intracellular accumulation of free fatty acids (FFAs) in 3T3-L1 adipocytes increased expression of inflammatory cytokines, whereas inhibiting ceramide synthesis partly blocked PAI-1 expression, but not IL-6. Induction of inflammatory markers in vivo and in vitro was preceded by phosphorylation of p38 and JNK, and inhibition of HSL prevented activation of these kinases. Experiments with pharmacological inhibitors of specific MAP kinases demonstrated the importance of p38 MAPK as a mediator of lipolysis-induced inflammation in vivo and in vitro. Together, these results demonstrate that FFAs liberated by HSL activate p38 and JNK, and p38 mediates pro-inflammatory cytokine expression in adipose tissue.     

Novel oxindole compounds inhibit the aggregation of amyloidogenic proteins associated with neurodegenerative diseases

Amyloidogenic proteins form aggregates in cells, thereby leading to neurodegenerative disorders, including Alzheimer's and prion's disease, amyotrophic lateral sclerosis (ALS) in humans, and degenerative myelopathy (DM) and cognitive dysfunction in dogs. Hence, many small-molecule compounds have been screened to examine their inhibitory effects on amyloidogenic protein aggregation. However, no effective drug suitable for transition to clinical use has been found. Here we examined several novel oxindole compounds (GIF compounds) for their inhibitory effects on aggregate formation of the canine mutant superoxide dismutase 1 (cSOD1 E40K), a causative mutation resulting in DM, using Thioflavin-T fluorescence. Most GIF compounds inhibited the aggregation of cSOD1 E40K. Among the compounds, GIF-0854-r and GIF-0890-r were most effective. Their inhibitory effects were also observed in cSOD1 E40K-transfected cells. Additionally, GIF-0890-r effectively inhibited the aggregate formation of human SOD1 G93A, a causative mutation of ALS. GIF-0827-r and GIF-0856-r also effectively inhibited aggregate formation of human prion protein (hPrP). Subsequently, the correlation between their inhibitory effects on cSOD1 and hPrP aggregation was shown, indicating GIF compounds inhibited the aggregate formation of multiple amyloidogenic proteins. Conclusively, the novel oxindole compounds (GIF-0827-r, GIF-0854-r, GIF-0856-r, and GIF-0890-r) are proposed as useful therapeutic candidates for amyloidogenic neurodegenerative disorders.     

Expression of CD55 and CD59 on peripheral blood cells from systemic lupus erythematosus (SLE) patients

CD55 and CD59 are glycosylphosphatidylinositol-anchored proteins with complement inhibitory properties. CD55 inhibits the formation of C3 convertases, and CD59 prevents the terminal polymerisation of the membrane attack complex. It has been reported that SLE patients seems to have an acquired deficiency of these proteins associated with secondary autoimmune haemolytic anaemia and lymphopenia. The aim of this study was to evaluate the presence of altered CD55 and CD59 expression on peripheral blood cells from SLE patients. Flow cytometric analyses were performed on red and white blood cells from 23 SLE patients and 23 healthy controls. We observed more CD55- and CD59-lymphocytes (p = 0.005 and p = 0.019, respectively), and CD59-granulocytes (p = 0.045) in SLE patients than in controls. These results suggest there is an altered pattern of CD55 and CD59 expression on the peripheral blood cells of SLE patients, and it may play a role in the cytopenias in these patients.     

Hepatitis B virus core protein interacts with CD59 to promote complement-mediated liver inflammation during chronic hepatitis B virus infection

The inflammatory response mediated by the immune system is the major cause of hepatitis B virus (HBV)-associated liver injury. Here, we identified CD59, as a novel HBc-interacting protein in hepatocytes by tandem affinity purification (TAP) screening. The expression of CD59 was markedly down-regulated in HBc-transfected HepG2 or HepG2.215 cells, which resulted in an upshift of hepatocyte sensitivity to membrane attack complex (MAC)-induced cell lysis. These results were consistent with the accumulation of MACs in the liver of HBV-infected patients. Additional analyses using laser confocal microscopy, quantitative PCR and flow cytometry revealed that CD59 was specifically translocated to the nucleus upon binding to HBc, which induced the down-regulation of CD59 on both the mRNA and protein levels.     

NMR relaxation studies of intracellular Na in red blood cells

The state of intracellular Na⁺ in human and dog erythrocytes was characterized by ²³Na-NMR using dysprosium complexes as shift reagents. Intracellular Na⁺ concentrations were determined using integration of the inner Na⁺ NMR signals and measurements of the intracellular volume using ⁵⁹Co-NMR of extracellular Co(CN)³⁻₆. T₂ was found to be significantly shorter than T₁, indicating some binding to macromolecules. While the longitudinal magnetization decay follows a single exponential the transverse magnetization could be fitted with a double-exponential function. It was shown that neither the binding to the inner side of the membrane nor binding to hemoglobin contributes to the relaxation enhancement.     

Field larvicidal and oviposition repellent efficacy of three essential oil formulations for the control of filaria vector mosquito Culex quinquefasciatus Say (Diptera: Culicidae): A kill and push concept

Biological control of larval mosquitoes is in great demand due to the development of resistance against synthetic insecticides, environmental toxicity and the inability to protect habitats from further oviposition. In the present study, three botanical essential oils (BEOs) – citronella, eucalyptus, and pine oils – were formulated for the assessment of larvicidal and oviposition repellent efficacies against Culex quinquefasciatus Say, the filaria vector. The GC–MS profiling of BEOs showed the presence of 16 – 19 compounds covering 87.7–93% of oil composition. The resistance status of Culex quinquefasciatus population was evaluated with temephos (LC₅₀ = 0.001 ppm, LC₉₀ = 0.01 ppm). Larval bioassay of emulsifiable concentrate (EC) formulations prepared from eucalyptus and pine oils showed promising efficacy (LC₅₀ = 22.7 and 23.2 ppm) and LC₉₀ (63.8 and 62.4 ppm) compared to citronella oil EC (LC₅₀ = 43.4 ppm and LC₉₀ = 199.0 ppm). The field trials of eucalyptus + pine (1:1 ratio) EC showed 100% larval mortality for 3 weeks at 300 ppm compared to 2 weeks of individual oils. Further, the oviposition attraction index (OAI) for ECs of eucalyptus, pine, and their combination showed complete protection of breeding habitats from oviposition at 1st week and ?0.9 to ?1.0 OAI at 2nd week with slight reduction to ?0.5 at 3rd week. Citronella EC provided shortest larvicidal and oviposition repellent efficacy under the field conditions. The promising mosquitocidal activities of EC formulations of eucalyptus and pine or their combination suggest them as potential biocontrol vector control candidates over citronella oil.