Wheat TaMYB1A Negatively Regulates the Phenylpropanoid Pathway and Plant Height / 中国生物化学与分子生物学报

The phenylpropanoid pathway is one of the important pathways for synthesizing plant secondary metabolites, which can produce lignin, flavonoid, and sinapoylmalate. These compounds can not only affect the plant growth, development, and stress response, but also be used to produce perfume, pesticide, dye, medicine, feed, and biomass energy. R2R3-MYBs play important roles in regulating plant secondary metabolism, organ development, and in responding to environmental stresses. Wheat (Triticum aestivum L.) is an important food crop, but lots of straw will be produced accompanied by grain yields. Therefore, elucidating the function and regulatory mechanism of R2R3 MYBs of wheat is crucial for the effective utilization of the wheat straw. RT-PCR results showed that TaMYB1A was highly expressed in the wheat stems, and the GFP-TaMYB1A fusion protein was mainly localized in the nucleus of the N. benthamiana epidermal cells. TaMYB1A has transcriptional repressive activity in yeast cells. In this study, TaMYB1A-overexpressed transgenic Arabidopsis lines were generated to elucidate the effect of overexpression of TaMYB1A on the biosynthesis of lignin and flavonoid. Our results suggested that overexpression of TaMYB1A inhibited the plant height (P < 0. 05) and decreased the lignin (P < 0. 05) and flavonoid (P < 0. 05) biosynthesis of the transgenic Arabidopsis plants significantly. TaMYB1A could bind to the promoters of the Arabidopsis At4CL1, AtC4H, AtC3H, and AtCHS as well as the wheat Ta4CL1 and TaC4H1 revealed by yeast one-hybrid (Y1H) assasy, the transcriptional repressive effect of TaMYB1A on At4CL1, AtC4H, AtC3H, and AtCHS was confirmed by dual-luciferase reporter systems and also on Ta4CL1 and TaC4H1 by a genetic approach. Gene chip and quantitative RT-PCR (qRT-PCR) results showed that overexpression of TaMYB1A down-regulated the expression of most of the key genes involved in the phenylpropanoid metabolism and decreased the 4CL activity (P < 0. 05) of the transgenic Arabidopsis plants significantly. As suggested above, the wheat TaMYB1A belongs to the subgroup 4 R2R3 MYB transcription factors. TaMYB1A could bind to the promoters of the key genes involved in phenylpropanoid metabolism, repress their expression and negatively regulate the phenylpropanoid metabolism pathway and plant height.

Mechanism of n-butanol alcohol extract of Baitouweng Decoction in treatment of vulvovaginal candidiasis based on negative regulation of NLRP3 inflammasome via PKCδ/NLRC4/IL-1Ra axis / 中国中药杂志

This study aimed to explore the mechanism of n-butanol alcohol extract of Baitouweng Decoction(BAEB) in the treatment of vulvovaginal candidiasis(VVC) in mice based on the negative regulation of NLRP3 inflammasome via PKCδ/NLRC4/IL-1Ra axis. In the experiment, female C57BL/6 mice were divided randomly into the following six groups: a blank control group, a VVC model group, high-, medium-, and low-dose BAEB groups(80, 40, and 20 mg·kg~(-1)), and a fluconazole group(20 mg·kg~(-1)). The VVC model was induced in mice except for those in the blank control group by the estrogen dependence method. After modeling, no treatment was carried out in the blank control group. The mice in the high-, medium-, and low-dose BAEB groups were treated with BAEB at 80, 40, and 20 mg·kg~(-1), respectively, and those in the fluconazole group were treated with fluconazole at 20 mg·kg~(-1). The mice in the VVC model group received the same volume of normal saline. The general state and body weight of mice in each group were observed every day, and the morphological changes of Candida albicans in the vaginal lavage of mice were examined by Gram staining. The fungal load in the vaginal lavage of mice was detected by microdilution assay. After the mice were killed, the degree of neutrophil infiltration in the vaginal lavage was detected by Papanicolaou staining. The content of inflammatory cytokines interleukin(IL)-1β, IL-18, and lactate dehydrogenase(LDH) in the vaginal lavage was tested by enzyme-linked immunosorbent assay(ELISA), and vaginal histopathology was analyzed by hematoxylin-eosin(HE) staining. The expression and distribution of NLRP3, PKCδ, pNLRC4, and IL-1Ra in vaginal tissues were measured by immunohistochemistry(IHC), and the expression and distribution of pNLRC4 and IL-1Ra in vaginal tissues were detected by immunofluorescence(IF). The protein expression of NLRP3, PKCδ, pNLRC4, and IL-1Ra was detected by Western blot(WB), and the mRNA expression of NLRP3, PKCδ, pNLRC4, and IL-1Ra was detected by qRT-PCR. The results showed that compared with the blank control group, the VVC model group showed redness, edema, and white secretions in the vagina. Compared with the VVC model group, the BAEB groups showed improved general state of VVC mice. As revealed by Gram staining, Papanicolaou staining, microdilution assay, and HE staining, compared with the blank control group, the VVC model group showed a large number of hyphae, neutrophils infiltration, and increased fungal load in the vaginal lavage, destroyed vaginal mucosa, and infiltration of a large number of inflammatory cells. BAEB could reduce the transformation of C. albicans from yeast to hyphae. High-dose BAEB could significantly reduce neutrophil infiltration and fungal load. Low-and medium-dose BAEB could reduce the da-mage to the vaginal tissue, while high-dose BAEB could restore the damaged vaginal tissues to normal levels. ELISA results showed that the content of inflammatory cytokines IL-1β, IL-18, and LDH in the VVC model group significantly increased compared with that in the blank control group, and the content of IL-1β, IL-18 and LDH in the medium-and high-dose BAEB groups was significantly reduced compared with that in the VVC model group. WB and qRT-PCR results showed that compared with the blank control group, the VVC model group showed reduced protein and mRNA expression of PKCδ, pNLRC4, and IL-1Ra in vaginal tissues of mice and increased protein and mRNA expression of NLRP3. Compared with the VVC model group, the medium-and high-dose BAEB groups showed up-regulated protein and mRNA expression of PKCδ, pNLRC4, and IL-1Ra in vaginal tissues and inhibited protein and mRNA expression of NLRP3 in vaginal tissues. This study indicated that the therapeutic effect of BAEB on VVC mice was presumably related to the negative regulation of NLRP3 inflammasome by promoting PKCδ/NLRC4/IL-1Ra axis.

Update in immune regulatory pathway of tumor necrosis factor-α-induced protein 8-like 2 / 中华危重病急救医学

The tumor necrosis factor-α-induced protein 8-like (TNFAIP8, TIPE) family is recently identified proteins consisting of four highly homologous mammalian proteins: TIPE, TIPE1, TIPE2, and TIPE3. Although the four members share similar molecular structure and function, involving effects in pathophysiological processes of inflammation, immunity, tumors, stroke, angiogenesis, and other diseases, they have individual characteristics. Many studies have shown that TIPE2 is an essential negative regulator of both innate and adaptive immunity. Up-regulation of TIPE2 expression can alleviate excessive inflammation during septic shock and maintain hemostasis of macrophages, neutrophils, dendritic cells, T cells, and B cells. In this review, we summarize the current literature for structure feature, immune function, and regulatory mechanism of TIPE2, together with its clinical significance in the pathogenesis of immune disorders of a wide array of human diseases. Understanding the basic biology of this new molecule might help us to seek novel strategies for the immunomodulation of human diseases.

The Role of Smad7 in Hepatocellular Carcinoma Proliferation and Migration and Its Clinical Significance / 现代生物医学进展

Objective:To investigate the role of Smad7 in the Hepatocellular carcinoma (HCC) migration and proliferation and its clinical significance.Methods:Through transfecting pcDNA3.1 (+)-Smad7 or siRNA Smad7 to overexpress or knockdown the Smad7 expression in HCC cell lines HepG2 and Huh7.The MTT assays were used to test the role of Smad7 in proliferation of HCC cells.Transwell and wound-healing assays were used to detect the effect of Smad7 on migratory ability in both tow cell lines.RT-PCR was used to test the Smad7 expression in 9 clinical HCC patients' specimens.Results:As the results,overexpression of Smad7 significantly inhibited the proliferation of cells compared with the control group,while knockdown Smad7 promoted the proliferation.At the same time,overexpression of Smad7 could inhibit the migratory ability of HCC cells compared with the control group,while knockdown smad7 could accelerate this ability.The expression of Smad7 in cancer tissue was significantly lower compared with normal mucosa tissue adjacent to cancer.Conclusions:Smad7 is a kind of anti-progressive molecule in HCC.

Research progress on negative regulation of adaptive immune response by NK cells / 中国免疫学杂志

Natural killer ( NK) cells are important innate effector cells and play a vital role in maintaining homeostasis through potent cytotoxic activity and cytokine production. Recent findings show that NK cells can also shape adaptive immune responses by in-fluencing a variety of immune cells. In addition to direct interactions with other immune cells,NK cells can indirectly stimulate or inhibit adaptive immune response via influencing infected cells and pathogen load. Abundant studies have highlighted the positive regulatory functions of NK cells, while their negative regulatory functions have increasingly attracted attention in recent years. Here, we review recent findings on negative regulation of adaptive immune response by NK cells, discussing the involved effector cells and function mechanism,and demonstrate how this negative regulation influences the overall outcome of adaptive immunity in infection and tumor disease.

Activation and regulation of NLRP3 inflammasome: Research progress / 第二军医大学学报

Inflammasome is a vital part of innate immunity, and NLRP3 inflammasome is by far the most thoroughly studied inflammasome complexes that have been described. NLRP3activating signals include toxins secreted by pathogens, crystalline moleculesand endogenous danger signals. Activation of NLRP3 inflammasome needs two steps: priming and activating. The priming step affects NLRP3 at the transcriptional and posttranscriptional modification levels * the activating step is associated with ion flowing, mitochondria and lysosomes. In this paper we also reviewed the negative regulation of NLRP3 inflammasome at the expression, assembly and activation levels.

Construction and screening of human immunodeficiency virus-1 negative regulation factor peptide-specific CD4+T lymphocyte clone / 中华传染病杂志

Objective To construct and screen the human immunodeficiency virus-1 (HIV-1) negative regulation factor (Nef) peptide-specific CD4+ T lymphocyte clone.Methods Peripheral blood mononuclear cells (PBMC) from five asymptomatic HIV-1 infected patients were collected and Bulkcultured with Nef end peptides.The CD4 molecule and intracellular interferon (IFN)-gamma of cultured cells were detected by two-color flow cytometry.The Nef end peptide-specific T cell clone was then constructed by limited dilution and confirmed through enzyme linked immunospot assay (ELISPOT).The best grown cells were selected and cultured as the final clone.Results The Nef end peptide-specific-T lymphocyte clone was successfully constructed from PBMC of one HIV-infected patient and confirmed by ELISPOT.The detection of human leukocyte antigen (HLA)-DRB1 type showed that the epitope of this peptide was probably HLA-DRB1 * 0406.Conclusion The Nef end specific-T cell clone is successfully constructed,and a new epitope in the C-terminus of Nef protein and its HLA restriction are identified.

Negative Regulation of Toll-like Receptors Signaling Pathways / 生物化学与生物物理进展

Toll-like receptors (TLRs) are key mediators of both innate and adaptive immunity by recognizing and eliciting responses to invading pathogens. The activation of TLRs must be stringently controlled in order to avoid exaggerated expression of signaling components as well as pro-inflammatory cytokines that can devastate the host,resulting in chronic inflammatory diseases,autoimmune disorders and aid in the pathogenesis of TLR-associated diseases. Therefore,it is essential that negative regulators act at multiple levels within TLR signaling cascades in order to synchronize the activation and negative regulation of signal transduction to limit potentially harmful immunological consequences. A summary of the various mechanisms employed by negative regulators of TLRs signaling to ensure the appropriate modulation of both immune and inflammatory responses was provided.

Negative Regulation of Intracellular Cytokine Signal Transduction / 대한류마티스학회지

Cytokines are secreted proteins and interact with their specific cell surface receptors, triggering intracellular signal transduction pathways that activate a number of genes crucial for the biological functions of cytokines. These cytokine signal transduction pathways are tightly regulated processes. The negative regulations of cytokine signaling are achieved by receptor internalization and degradation, dephosphorylation of signaling intermediates, expression of protein inhibitors such as suppressor of cytokine signaling (SOCS) and protein inhibitors of activated STAT (PIAS). The observation that cytokines are central to the inflammatory and destructive process in several autoimmune diseases suggests that interventions targeting the cytokine intracellular signaling will be a new therapeutic strategy in autoimmune diseases. We review the current knowledge about negative regulation of cytokine signal transduction.