Identification and application of anti-inflammatory compounds screening system based on RAW264.7 cells stably expressing NF-κB-dependent SEAP reporter gene

In Vitro Anti-Inflammatory Study of Limonoids Isolated from Chisocheton Plants

Chisocheton plants from the family Meliaceae have traditionally been used to treat several diseases; however, scientific evidence is limited. The most abundant chemical constituents of this plant are the limonoids, which are known for their various biological activities, including anti-inflammatory effects. However, the anti-inflammatory effects and underlying mechanisms of action of the constituents of Chisocheton plants have not been fully explored. In this report, we evaluated the anti-inflammatory activity of 17 limonoid compounds from Chisocheton plant primarily by measuring their inhibitory effects on the production of pro-inflammatory cytokines, including TNF-α, IL-6, IL-1β, and MCP-1, in LPS-stimulated THP-1 cells using an ELISA assay. Compounds 3, 5, 9, and 14-17 exhibited significant activity in inhibiting the evaluated pro-inflammatory markers, with IC50 values less than 20 µM and a high selectivity index (SI) range. Compounds 3, 5, 9, and 15 significantly suppressed the expression of phosphorylated p38 MAPK in THP-1 cells stimulated with LPS. These findings support the use of limonoids from Chisocheton plants as promising candidates for anti-inflammatory therapy.

Phytochemical Profile and Anti-Inflammatory Activity of the Fraction from Artemisia lavandulaefolia

Artemisia lavandulaefolia, a traditional herbal medicine, has been utilized as anti-inflammatory and analgesia agent in clinic. Bioassay-guided fractionation resulted in a fraction (ALDF) with anti-inflammatory effect obtained from A. lavandulaefolia. Its main constituents were analyzed and identified by UPLC-ESI-Q-TOF-MS technology. ALDF showed the strong inhibitory activity on the nitrogen oxide (NO) production in LPS-induced RAW 264.7 macrophages with an IC₅₀ value of 1.64±0.41 μg/mL. Further results displayed that ALDF also significantly suppressed the secretion of key pro-inflammatory mediators, including tumor necrosis factor-α (TNF-α), prostaglandin E₂ (PGE₂ ) and interleukin-1β (IL-1β), and the increase of the inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein expression induced by LPS stimulation. Mechanism study indicated that ALDF was able to block NF-κB signaling pathway through inhibiting IκB and p65 phosphorylation, as well as NF-κB p65 nuclear translocation. Furthermore, in vivo results in mice revealed that treatments with ALDF evoked significant inhibition on ear edema induced by xylene and on the writhing responses induced by acetic acid. These results suggest that ALDF holds great potential in the prevention and treatment of inflammatory disorders.

Possible Strategies to Optimize a Biomarker Discovery Approach to Correlate with Neurological Outcome in Patients with Spinal Cord Injury: A Pilot Study

The lack of reliable diagnostic and prognostic markers for spinal cord injured (SCI) patients is a severe obstacle in development and testing of new therapies, and it also impairs appropriate rehabilitation care. The sparse available data on the biochemical composition of cerebrospinal fluid (CSF) during the acute and/or chronic phase of the lesion provide, up until now, inconsistent results. In this pilot study, we then explored the possibility of combining a multi-parametric and bioinformatic analysis of CSF for its biological properties tested on different cells types, suitable for investigating inflammation and re-myelination. The patient enrollment was based on stringent inclusion criteria; that is, cervical and thoracic SCI trauma, CSF collection within 24 h of trauma, type of surgical approach for spine stabilization, and absence of steroid therapy before CSF collection. Eleven SCI patients and four healthy controls were included, and in three patients, CSF was also collected at 3 months after lesion. We identified 19 proteins among the 60 investigated cytokines, chemokines, growth factors, and structural biomarkers, which are transiently regulated 24 h after SCI. A bioinformatic analysis indicated that interleukin (IL)-6 and IL-10 are in the core of the interconnected net of activated proteins. Cell-based experiments indicate that CSF from SCI patients stimulates astroglia derivation from neural precursor cells, and an inverse correlation between IL-8 CSF level and oligodendrocyte precursor cells generated from neural stem cells was also observed. Results from this pilot study suggest that using a combined bioanalytic and biological approach to analyze SCI CSF at different times after injury could be a useful approach for identifying reliable diagnostic and prognostic markers in SCI.

Programmed cell death protein 4 deficiency suppresses foam cell formation by activating autophagy in advanced glycation end-product low-density lipoprotein-induced macrophages

BACKGROUND

Advanced glycation end-product is a modified form of low-density lipoprotein (AGE-LDL) and accelerates atherosclerosis through undefined mechanisms. Programmed cell death protein 4 (PDCD4), a transcriptional regulator, plays an important role in the regulation of autophagy. The aim of the present study was to investigate the role of PDCD4 involved in AGE-LDL-induced foam cell formation.

METHODS

The characterization of AGE-LDL was measured by the thiobarbituric assay and agarose gel electrophoresis in vitro. RAW264.7, THP-1 cell line and primary peritoneal macrophages of mice were transfected with shPDCD4 plasmid AGE-LDL-induced foam cell formation was stained by Oil Red, and the levels of autophagy and apoptosis were determined by Western blot analysis. Autophagosome was observed with immunofluorescence microscopy. Mitochondrial membrane potential and autophagic flux were assessed by flow cytometry.

RESULTS

AGE modification resulted in significant reduction of absorbance shown by thiobarbituric assay and augmentation of electrophoresis mobility. Further studies suggest that macrophages exposed AGE-LDL triggered autophagy in the early stage of foam cell formation. PDCD4 deficiency enhanced lipoautophagy but inhibited apoptosis and mitochondria dysfunction. Previous studies have been reported that autophagy is an adaptive response might prevent lesional macrophage apoptosis. In our study, we found PDCD4 deficiency attenuated apoptosis and AGE-LDL-induced foam cell formation relied on increased autophagy.

CONCLUSION

Our data revealed that PDCD4 deficiency can facilitate autophagy and benefit for AGE-LDL-induced foam cell formation.

Immunomodulatory activity of a water-soluble polysaccharide obtained from highland barley on immunosuppressive mice models

A water-soluble polysaccharide (BP-1) was extracted and purified from highland barley (Hordeum vulgare L.) and its average molecular weight was about 6.7 × 104 Da. In this study, the immunomodulatory activity of BP-1 on the immunosuppressive BALB/c mice model and its molecular mechanism were elucidated. It was found that the weight indexes of spleen and thymus were significantly increased by BP-1 (80 mg kg-1 and 160 mg kg-1) treatment in the immunosuppressive mice model. The results showed that BP-1 (80 mg kg-1 and 160 mg kg-1) could significantly increase the number of bone marrow cells (BMC) and peripheral blood white blood cells (WBC) in the immunosuppressive mice model. In addition, the result further confirmed that BP-1 could increase the serum levels of IL-2, TNF-α and IFN-γ, so as to improve the immune function of immunosuppressive mice. The results showed that BP-1 (80 mg kg-1 and 160 mg kg-1) could promote the proliferation of spleen cells and the natural killer (NK) cell activity in vivo. The quantitative real-time polymerase chain reaction (qRT-PCR) and ELISA results revealed that BP-1 (80 mg kg-1 and 160 mg kg-1) could enhance the production of IL-2, TNF-α, IFN-γ, IgG and IgM in the spleen of immunosuppressive mice. The HE (hematoxylin and eosin) stained histopathological images showed that BP-1 (80 mg kg-1 and 160 mg kg-1) could repair the damage induced by CTX in the spleen cells of immunosuppressive mice. The result of macrophages showed that BP-1 (80 mg kg-1 and 160 mg kg-1) could promote the proliferation and phagocytosis activity of macrophages in immunosuppressive mice. Furthermore, BP-1 could activate macrophages by the TLR-4, TRAF6, TAK1 and nuclear factor κB (NF-κB) p65 pathways in vivo. These results suggested that BP-1 has a remarkable immunomodulatory activity on the immunosuppressive mice model.

The immunomodulatory activity and mechanism of docosahexenoic acid (DHA) on immunosuppressive mice models

In this study, the immunomodulatory activity of docosahexaenoic acid (DHA) on the immunosuppressive BALB/c mice model and its molecular mechanism are elucidated. It was found that the weight indexes of the spleen and thymus were significantly increased by DHA (44.0 mg kg-1 and 88.0 mg kg-1) treatment in the prevention or cure groups. The result of macrophages showed that DHA (44.0 mg kg-1 and 88.0 mg kg-1) could promote the proliferation and phagocytosis activity of macrophages in the prevention or cure groups. In addition, DHA could activate macrophages by the G-protein coupled cell membrane receptor GPR120- Mitogen-Activated Protein Kinases (MAPKs)-nuclear factor κB (NF-κB) p65 pathway in vivo. The result of the spleen showed that DHA (44.0 mg kg-1 and 88.0 mg kg-1) could promote the proliferation of spleen cells and the natural killer (NK) cells activity in vivo. In the prevention or cure groups, the quantitative real-time polymerase chain reaction (qRT-PCR) results revealed that DHA (44.0 mg kg-1 and 88.0 mg kg-1) could enhance the production of cytokines IL-1β, IL-2, TNF-α and IFN-γ in the spleen of immunosuppressive mice. The HE (hematoxylin and eosin) stained histopathological images showed that DHA could repair the damage induced by CTX in the spleen cells of the prevention or cure groups. These results suggested that DHA has a remarkable immunomodulatory activity on the immunosuppressive mice model in the prevention or cure groups.

A human monocytic NF-κB fluorescent reporter cell line for detection of microbial contaminants in biological samples

Sensing of pathogens by innate immune cells is essential for the initiation of appropriate immune responses. Toll-like receptors (TLRs), which are highly sensitive for various structurally and evolutionary conserved molecules derived from microbes have a prominent role in this process. TLR engagement results in the activation of the transcription factor NF-κB, which induces the expression of cytokines and other inflammatory mediators. The exquisite sensitivity of TLR signalling can be exploited for the detection of bacteria and microbial contaminants in tissue cultures and in protein preparations. Here we describe a cellular reporter system for the detection of TLR ligands in biological samples. The well-characterized human monocytic THP-1 cell line was chosen as host for an NF-ᴋB-inducible enhanced green fluorescent protein reporter gene. We studied the sensitivity of the resultant reporter cells for a variety of microbial components and observed a strong reactivity towards TLR1/2 and TLR2/6 ligands. Mycoplasma lipoproteins are potent TLR2/6 agonists and we demonstrate that our reporter cells can be used as reliable and robust detection system for mycoplasma contaminations in cell cultures. In addition, a TLR4-sensitive subline of our reporters was engineered, and probed with recombinant proteins expressed in different host systems. Bacterially expressed but not mammalian expressed proteins induced strong reporter activity. We also tested proteins expressed in an E. coli strain engineered to lack TLR4 agonists. Such preparations also induced reporter activation in THP-1 cells highlighting the importance of testing recombinant protein preparations for microbial contaminations beyond endotoxins. Our results demonstrate the usefulness of monocytic reporter cells for high-throughput screening for microbial contaminations in diverse biological samples, including tissue culture supernatants and recombinant protein preparations. Fluorescent reporter assays can be measured on standard flow cytometers and in contrast to established detection methods, like luciferase-based systems or Limulus Amebocyte Lysate tests, they do not require costly reagents.