Mingna Sun

Discovery and Optimization of Novel 3-Piperazinylcoumarin Antagonist of Chemokine-like Factor 1 with Oral Antiasthma Activity in Mice

Chemokine-like factor 1 (CKLF1) is a novel functional cytokine that acts through its receptor CC chemokine receptor 4 (CCR4). Activation of CCR4 by CKLF1 plays an important role in diseases such as asthma and multiple sclerosis. This article describes a cell-based screening assay using an FITC-labeled CCR4 agonist (CKLF1-C27), a CKLF1 peptide fragment. Screening of our in-stock small-molecule library identified a 3-piperazinylcoumarin analogue 1 (IC(50) = 4.36 x 10(-6) M) that led to the discovery of orally active compound 41 (IC(50) = 2.12 x 10(-8) M) through systematic optimization. Compound 41 blocked the calcium mobilization and chemotaxis induced by CKLF1-C27 and reduced the asthmatic pathologic changes in lung tissue of human CKLF1-transfected mice. Further studies indicated that compound 41 ameliorated pathological changes via inhibition of the NF-kappaB signal pathway.

Whole cell screen for inhibitors of pH homeostasis in Mycobacterium tuberculosis

Bacterial pathogens like Mycobacterium tuberculosis (Mtb) encounter acidic microenvironments in the host and must maintain their acid-base homeostasis to survive. A genetic screen identified two Mtb strains that cannot control intrabacterial pH (pHIB) in an acidic environment; infection with either strain led to severe attenuation in mice. To search for additional proteins that Mtb requires to survive at low pH, we introduced a whole-cell screen for compounds that disrupt pHIB, along with counter-screens that identify ionophores and membrane perturbors. Application of these methods to a natural product library identified four compounds of interest, one of which may inhibit novel pathway(s). This approach yields compounds that may lead to the identification of pathways that allow Mtb to survive in acidic environments, a setting in which Mtb is resistant to most of the drugs currently used to treat tuberculosis.

Effect of compound IMMLG5521, a novel coumarin derivative, on carrageenan-induced pleurisy in rats.

Accumulative evidences have showed that some coumarin derivatives have significantly anti-inflammatory effects. To investigate the potential anti-inflammatory effect of compound IMMLG5521, a novel coumarin derivative, carrageenan-induced pleurisy model in rats was employed. The results showed that IMMLG5521 (5, 10 and 20 mg/kg) exhibited anti-inflammatory effects, reducing pleural exudate formation, decreasing total number of inflammation cells and polymorphonuclear leukocytes infiltration, attenuating histological injury and reducing TNF-α, IL-1β, MIP-2 and IL-8 release. Further investigation revealed that the compound may exert its anti-inflammatory effect via inhibiting nuclear translocation of NF-кB in inflammatory cells collected from pleural exudates. Taken together, the present results suggested that IMMLG5521 inhibited acute inflammation in carrageenan-induced pleurisy model that could be, in part, related to a reduction of release of inflammatory factors, another part may be related to an inhibition of NF-кB activation.

IMM-H004, a novel coumarin derivative compound, attenuates the production of inflammatory mediatory mediators in lipopolysaccharide-activated BV2 microglia

Therapeutic strategies designed to inhibit the activation of microglia may lead to significant advancement in the treatment of most neurodegenerative diseases. 7-hydroxy-5-methoxy-4-methyl-3-(4-methylpiperazin-1-yl)-coumarin (IMM-H004) is a novel compound and has been reported exerting potent neuroprotective effects which may be related to anti-inflammation. In the present study, the anti-inflammatory effects of IMM-H004 were investigated in lipopolysaccharide (LPS)-treated BV2 microglia. Our observations indicated that treatment with IMM-H004 significantly inhibited BV2 microglia activation, protected PC12 cells and primary neurons against indirect toxicity mediated by exposure to conditioned medium (CM) from LPS-treated BV2 cells. Additionally, IMM-H004 significantly suppressed the release of TNF-α, IL-1β and NO, and suppressed the expression of pro-inflammatory mediators and cytokines such as iNOS, COX-2, and IL-6 in LPS-stimulated BV2 microglia. The nuclear translocation of NF-κB and the phosphorylation level of JNK and p38 MAPK pathways were also inhibited by IMM-H004 in LPS-treated BV2 microglia. Moreover, IMM-H004 also was a strong selective OH scavenger whose effect was similar with vitamin C. Overall, our findings suggested that IMM-H004 might be a promising therapeutic agent for alleviating the progress of neurodegenerative diseases associated with microglia activation.

Anti-inflammatory effect of IMMLG5521, a coumarin derivative, on Sephadex-induced lung inflammation in rats

The study is to investigate the effect of compound IMMLG5521, a coumarin derivative, on lung inflammation induced by Sephadex in rats. Sephadex led to massive granulomas, infiltration of neutrophils and eosinophils, the increase of TNF-α level in BALF and lung tissue. Sephadex injection led to the up-regulation of VCAM-1 and ICAM-1 expressions in the lungs. However, pretreatment with IMMLG5521 (6.25 and 12.5 mg/kg) inhibited massive granulomas and infiltration of neutrophils and eosinophils, decreased TNF-α level in BALF and lung tissue, and down-regulated VCAM-1 and ICAM-1 expressions in the lung tissue. In conclusion, compound IMMLG5521 may suppress the lung injury induced by Sephadex, at least in part, due to the prevention of the up-regulation of VCAM-1 and ICAM-1 expressions and TNF-α level.

IMM-H004, a novel courmarin derivative, protects against oxygen-and glucose-deprivation/restoration-induced apoptosis in PC12 cells

7-Hydroxy-5-methoxy-4-methyl-3-(4-methylpiperazin-1-yl)-coumarin (IMM-H004) is a novel coumarin derivative synthesized in our laboratory. The purpose of the current study was to determine the neuroprotective effects of IMM-H004 on PC12 cells and its potential mechanism of action. PC12 cells were subject to oxygen and glucose deprivation (OGD) followed by the restoration of oxygen and glucose (R), which mimics ischemia and reperfusion in vivo. Cell viability was determined by MTT assay. DNA fragmentation was analyzed by DNA ladder. ROS and mitochondrial membrane potential were measured by fluorescent microscope and quantified by Image-Pro Express 6.0 software. ATP was measured by luciferin-luciferase assay. The activation of signal-regulated molecules was assessed by the Western blot analysis. OH formation was determined using the Electron Spin Resonance (ESR) trapping technique in combination with 5, 5-dimethyl-1-pyrroline-N-oxide. OGD/R reduced cell viability and induced cell apoptosis, which were both dose-dependently attenuated by IMM-H004. The accumulation of intracellular reactive oxygen species (ROS) and reduced mitochondrial membrane potential observed in PC12 cells treated with OGD/R, which switch on the mitochondrion-dependent apoptotic pathway, were reversed by IMM-H004. ATP production in OGD/R-treated PC12 cells was elevated by IMM-H004, which suggests that it restored the functions of the mitochondria. OGD/R-induced cytochrome c release from the mitochondria reduced the ratio of apoptotic proteins, Bcl-2/Bax, and induced caspase-3 activation and DNA fragmentation. These changes were significantly inhibited by IMM-H004. IMM-H004 also significantly inhibited OH formation, determined by electron spin resonance, which indicates that it is a potent free-radical scavenger. This study has demonstrated that IMM-H004 protects PC12 cells against OGD/R-induced apoptosis, at least in part, by scavenging excessive ROS and inhibiting the mitochondrion-dependent apoptotic pathway.

In vitro and in vivo anti-inflammatory effects of IMMLG5521, a coumarin derivative.

Several coumarin derivatives have been reported to present multiple biological activities. In this study, in vitro the compound IMMLG5521 (0.1, 1, 10μM) can inhibit the release of β-glucuronidase from PAF-stimulated polymorphonuclear leukocytes, the compound IMMLG5521 (0.1, 1, 10μM) can inhibit NO production and decrease TNF-α and IL-β release from LPS-stimulated RAW264.7 cells. In vivo, we evaluated the effect of IMMLG5521 on acute and chronic inflammation models. Our data showed that IMMLG5521 (6mg/kg, 12mg/kg) could inhibit xylene-induced ear swelling and cotton pellet-induced granuloma formation in mice. Taken together, the compound IMMLG5521 inhibited the release of inflammatory factors and mediators in vitro, decreased inflammation response in mice. The compound IMMLG5521 can inhibit inflammation in vitro and in vivo.

Identification of Rv3852 as an Agrimophol-Binding Protein in Mycobacterium tuberculosis

Mycobacterial tuberculosis (Mtb) is able to preserve its intrabacterial pH (pHIB) near neutrality in the acidic phagosomes of immunologically activated macrophages and to cause lethal pathology in immunocompetent mice. In contrast, when its ability to maintain pHIB homeostasis is genetically compromised, Mtb dies in acidic phagosomes and is attenuated in the mouse. Compounds that phenocopy the genetic disruption of Mtb’s pHIB homeostasis could serve as starting points for drug development in their own right or through identification of their targets. A previously reported screen of a natural product library identified a phloroglucinol, agrimophol, that lowered Mtb’s pHIB and killed Mtb at an acidic extrabacterial pH. Inability to identify agrimophol-resistant mutants of Mtb suggested that the compound may have more than one target. Given that polyphenolic compounds may undergo covalent reactions, we attempted an affinity-based method for target identification. The structure-activity relationship of synthetically tractable polyhydroxy diphenylmethane analogs with equivalent bioactivity informed the design of a bioactive agrimophol alkyne. After click-chemistry reaction with azido-biotin and capture on streptavidin, the biotinylated agrimophol analog pulled down the Mtb protein Rv3852, a predicted membrane protein that binds DNA in vitro. A ligand-protein interaction between agrimophol and recombinant Rv3852 was confirmed by isothermal calorimetry (ITC) and led to disruption of Rv3852’s DNA binding function. However, genetic deletion of rv3852 in Mtb did not phenocopy the effect of agrimophol on Mtb, perhaps because of redundancy of its function.