Evaluation of Resistance Resources and Analysis of Resistance Mechanisms of Maize to Stalk Rot Caused by Fusarium graminearum.

Stalk rot is one of the most destructive and widely distributed diseases in maize plants worldwide. Research on the performance and resistance mechanisms of maize against stem rot is constantly improving. In this study, among 120 inbred maize lines infected by Fusarium graminearum using the injection method, 4 lines (3.33%) were highly resistant to stalk rot, 28 lines (23.33%) were resistant, 57 lines (47.50%) were susceptible, and 31 lines (25.84%) were highly susceptible. The inbred lines 18N10118 and 18N10370 were the most resistant and susceptible with disease indices of 7.5 and 75.6, respectively. Treatment of resistant and susceptible maize inbred seedlings with F. graminearum showed that root hair growth of the susceptible inbred lines was significantly inhibited, and a large number of hyphae attached and adsorbed multiple conidia near the root system. However, the resistant inbred lines were delayed and inconspicuous, with only a few hyphae and spores appearing near the root system. Compared with susceptible inbred lines, resistant maize inbred line seedlings treated with F. graminearum exhibited elevated activities of catalase, phenylalanine ammonia-lyase, polyphenol oxidase, and superoxide dismutase. We identified 153 genes related to disease resistance by transcriptome analysis. The mitogen-activated protein kinase signaling and peroxisome pathways mainly regulated the resistance mechanism of maize inbred lines to F. graminearum infection. These two pathways might play an important role in the disease resistance mechanism, and the function of genes in the two pathways must be further studied, which might provide a theoretical basis for further understanding the molecular resistance mechanism of stalk rot and resistance gene mining.

The role of ferroptosis in diabetic cardiovascular diseases and the intervention of active ingredients of traditional Chinese medicine.

Cardiovascular diseases (CVDs), encompassing ischaemic heart disease, cardiomyopathy, and heart failure, among others, are the most prevalent complications of diabetes and the leading cause of mortality in patients with diabetes. Cell death modalities, including apoptosis, necroptosis, and pyroptosis, have been demonstrated to be involved in the pathogenesis of CVDs. As research progresses, accumulating evidence also suggests the involvement of ferroptosis, a novel form of cell death, in the pathogenesis of CVDs. Ferroptosis, characterised by iron-dependent lipid peroxidation, which culminates in membrane rupture, may present new therapeutic targets for diabetes-related cardiovascular complications. Current treatments for CVDs, such as antihypertensive, anticoagulant, lipid-lowering, and plaque-stabilising drugs, may cause severe side effects with long-term use. Traditional Chinese medicine, with its broad range of activities and minimal side effects, is widely used in China. Numerous studies have shown that active components of Chinese medicine, such as alkaloids, polyphenols, and saponins, can prevent CVDs by regulating ferroptosis. This review summarises the recent findings on the regulatory mechanisms of active components of Chinese medicine against ferroptosis in CVDs, aiming to provide new directions and a scientific basis for targeting ferroptosis for the prevention and treatment of diabetic CVDs.

Characterization of inflammatory profiles and endothelial dysfunction in diabetic limb arterial occlusion.

Our study aims to detect the changes of adiponectin (APN), endothelin 1 (ET)-1, nitric oxide (NO), cystatin C (cysC) in diabetic limb arterial occlusion (DLAO) patients and unravel their associations with endothelial function. Total 240 type 2 diabetes mellitus (T2DM) patients were divided into a DM group (n = 80, ankle brachial index (ABI) ≥ 0.9) and a DLAO group (n = 160, ABI < 0.9). ABI, flow-mediated dilation (FMD) and nitroglycerin-mediated dilation (NMD), serum APN, ET-1, NO, and cysC were compared. There were significant increases in cysC and ET-1, and significant decreases in APN, NO, FMD and NMD of DLAO patients compared to T2DM patients. Serum APN and NO were positively correlated with ABI, while serum cysC and ET-1 were negatively correlated with ABI. cysC, ET-1 and diastolic blood pressure (DBP) were independent predictors of the severity of DLAO. Serum APN was positively correlated with FMD, NMD and NO, but was negatively correlated with ET-1 and cysC. FMD and NMD were positively correlated with APN and NO, and negatively correlated with ET-1 and cysC. Our study deciphers opposite roles of APN, NO, cysC and ET-1 in the development of DLAO and maintaining endothelial function.

An activated Th17-prone T cell subset involved in chronic graft-versus-host disease sensitive to pharmacological inhibition.

Chronic graft-versus-host disease (cGvHD) remains a major complication of allogeneic stem cell transplantation requiring novel therapies. CD146 and CCR5 are expressed by activated T cells and associated with increased T cell migration capacity and Th17 polarization. We performed a multiparametric flow cytometry analysis in a cohort of 40 HSCT patients together with a cGvHD murine model to understand the role of CD146-expressing subsets. We observed an increased frequency of CD146+ CD4 T cells in the 20 patients with active cGvHD with enhanced RORγt expression. This Th17-prone subset was enriched for cells coexpressing CD146 and CCR5 that harbor mixed Th1/Th17 features and were more frequent in cGvHD patients. Utilizing a murine cGvHD model with bronchiolitis obliterans (BO), we observed that donor T cells from CD146-deficient mice versus those from WT mice caused significantly reduced pulmonary cGvHD. Reduced cGvHD was not the result of failed germinal center B cell or T follicular helper cell generation. Instead, CD146-deficient T cells had significantly lower pulmonary macrophage infiltration and T cell CCR5, IL-17, and IFN-γ coexpression, suggesting defective pulmonary end-organ effector mechanisms. We, thus, evaluated the effect of TMP778, a small-molecule RORγt activity inhibitor. TMP778 markedly alleviated cGvHD in murine models similarly to agents targeting the Th17 pathway, such as STAT3 inhibitor or IL-17-blocking antibody. Our data suggest CD146-expressing T cells as a cGvHD biomarker and suggest that targeting the Th17 pathway may represent a promising therapy for cGvHD.

5-Fluorouracil targets thymidylate synthase in the selective suppression of TH17 cell differentiation.

While it is well established that treatment of cancer patients with 5-Fluorouracil (5-FU) can result in immune suppression, the exact function of 5-FU in the modulation of immune cells has not been fully established. We found that low dose 5-FU selectively suppresses TH17 and TH1 cell differentiation without apparent effect on Treg, TH2, and significantly suppresses thymidylate synthase (TS) expression in TH17 and TH1 cells but has a lesser effect in tumor cells and macrophages. Interestingly, the basal expression of TS varies significantly between T helper phenotypes and knockdown of TS significantly impairs TH17 and TH1 cell differentiation without affecting the differentiation of either Treg or TH2 cells. Finally, low dose 5-FU is effective in ameliorating colitis development by suppressing TH17 and TH1 cell development in a T cell transfer colitis model. Taken together, the results highlight the importance of the anti-inflammatory functions of low dose 5-FU by selectively suppressing TH17 and TH1 immune responses.

Targeting Th17 Effector Cytokines for the Treatment of Autoimmune Diseases.

Interleukin (IL)-17-producing T cells, especially T helper (Th)17 cells, play a critical role in the pathogenesis of a variety of autoimmune inflammatory diseases. The pathogenic function of Th17 cells results from their production of Th17 effector cytokines, namely IL-17 (or IL-17A), IL-17F, IL-22 and IL-26. The importance of IL-17 has been demonstrated by antibody neutralization studies in both animal models of autoimmune diseases as well as in human clinical trials. This review highlights the current knowledge of the clinical aspects of the Th17 cytokines as well as therapeutic antibodies against IL-17, IL-17F, IL-17 receptor, IL-22, IL-26 and granulocyte macrophage colony-stimulating factor for the future treatment of autoimmune inflammatory diseases.

Small-molecule RORγt antagonists inhibit T helper 17 cell transcriptional network by divergent mechanisms.

We identified three retinoid-related orphan receptor gamma t (RORγt)-specific inhibitors that suppress T helper 17 (Th17) cell responses, including Th17-cell-mediated autoimmune disease. We systemically characterized RORγt binding in the presence and absence of drugs with corresponding whole-genome transcriptome sequencing. RORγt acts as a direct activator of Th17 cell signature genes and a direct repressor of signature genes from other T cell lineages; its strongest transcriptional effects are on cis-regulatory sites containing the RORα binding motif. RORγt is central in a densely interconnected regulatory network that shapes the balance of T cell differentiation. Here, the three inhibitors modulated the RORγt-dependent transcriptional network to varying extents and through distinct mechanisms. Whereas one inhibitor displaced RORγt from its target loci, the other two inhibitors affected transcription predominantly without removing DNA binding. Our work illustrates the power of a system-scale analysis of transcriptional regulation to characterize potential therapeutic compounds that inhibit pathogenic Th17 cells and suppress autoimmunity.

Proviral integration site 2 is required for interleukin-6 expression induced by interleukin-1, tumour necrosis factor-α and lipopolysaccharide.

PIM (proviral integration site) kinases are a distinct class of serine/threonine-specific kinases consisting of PIM1, PIM2 and PIM3. PIM2 is known to function in apoptosis pathways. Expression of PIM2 is highly induced by pro-inflammatory stimuli but the role of PIM2 in the expression of pro-inflammatory cytokines is unclear. In this study, we showed that over-expression of PIM2 in HeLa cells as well as in human umbilical vein endothelial cells enhanced interleukin-1ß (IL-1ß) -induced and tumour necrosis factor-α-induced IL-6 expression, whereas over-expression of a kinase-dead PIM2 mutant had the opposite effect. Studies with small interfering RNA specific to PIM2 further confirmed that IL-6 expression in HeLa cells requires PIM2. To investigate the function of PIM2 further, we generated PIM2-deficient mice. It was found that IL-6 production was significantly decreased from PIM2-deficient spleen cells after stimulation with lipopolysaccharide. Taken together, we demonstrated an important function of PIM2 in controlling the expression of the pro-inflammatory cytokine IL-6. PIM2 inhibitors may be beneficial for IL-6-mediated diseases such as rheumatoid arthritis.

Interleukin 10 suppresses Th17 cytokines secreted by macrophages and T cells.

IL-17 and IL-22 are typical cytokines produced by the Th17 T cell subset, but it is unclear if Th17 cytokines can be produced by other cell types. We demonstrate that IL-10-deficient and IL-10R-deficient macrophages stimulated with lipopolysaccharide produce high levels of IL-17 and IL-22. Addition of exogenous IL-10 to IL-10-deficient macrophages abolished IL-17 production. When IL-10-deficient and IL-10R-deficient splenocytes were cultured under Th17 polarizing conditions, the population of IL-17-producing cells was increased and the cultures produced significantly higher levels of IL-17 and IL-22. The addition of recombinant IL-10 to IL-10-deficient splenocytes significantly decreased the percentage of IL-17-producing CD4(+) T cells. Finally, the mRNA for the Th17 transcription factor retinoic acid-related orphan receptor (ROR)gammat was significantly elevated in IL-10-deficient spleen cells and macrophages. These data demonstrate that Th17 cytokines and RORgammat are also expressed in macrophages and that IL-10 negatively regulates the expression of Th17 cytokines and RORgammat by both macrophages and T cells.

Epstein-Barr virus-induced gene 3 negatively regulates IL-17, IL-22 and RORgamma t.

Epstein-Barr virus-induced gene 3 (EBI3) associates with p28 to form IL-27 and with IL-12p35 to form IL-35. IL-27Ralpha(-/-) mice studies indicate that IL-27 negatively regulates Th17 cell differentiation. However, no EBI3, p28 or p35-deficiency studies that directly address the role of EBI3, p28 or p35 on Th17 cells have been done. Here, we demonstrate that spleen cells derived from EBI3(-/-) mice produce significantly higher levels of IL-17 as well as IL-22 upon stimulation with OVA. In vitro derived EBI3(-/-) Th17 cells also produced significantly higher levels of IL-17 and IL-22 than WT cells. The frequency of IL-17-producing cells was also elevated when EBI3(-/-) cells were cultured under Th17 conditions. In addition, spleen cells from EBI3(-/-) mice immunized with Listeria monocytogenes produced significantly elevated levels of IL-17 and IL-22. Furthermore, the Th17 transcription factor RORgamma t was significantly enhanced in EBI3(-/-) cells. Finally, EBI3(-/-) mice exhibited a reduced bacterial load following an acute challenge with L. monocytogenes or a re-challenge of previously immunized mice, suggesting that EBI3 negatively regulates both innate and adaptive immunity. Taken together, these data provide direct evidence that EBI3 negatively regulates the expression of IL-17, IL-22 and RORgamma t as well as protective immunity against L. monocytogenes.

Involvement of GATA3 in protein kinase C theta-induced Th2 cytokine expression.

Protein kinase C theta (PKCtheta) is essential for T cell activation, as it is required for the activation of NF-kappaB and expression of IL-2. PKCtheta has also been shown to affect NFAT activation and Th2 differentiation. To better understand the role of PKCtheta in the regulation of T helper cells, we used PKCtheta-deficient DO11.10 transgenic T cells to study its role in vitro. DO11.10 Th1 cells deficient in PKCtheta produced significantly less TNF-alpha and IL-2. The expression of Th2 cytokines, including IL-4, IL-5, IL-10, IL-13 and IL-24 was significantly reduced in PKCtheta-deficient T cells. Moreover, the expression of the Th2 transcription factor, GATA3, was significantly reduced in PKCtheta-deficient T cells. Overexpression of GATA3 by retroviral infection in PKCtheta-deficient T cells resulted in increased expansion of IL-4-producing T cells and higher IL-4 production than that of wild type Th2 cells. IL-5, IL-10, IL-13 and IL-24 expressions were also rescued by GATA3 overexpression. Our observations suggest that PKCtheta regulates Th2 cytokine expression via GATA3.

Sphingosine kinase 1 is a negative regulator of CD4+ Th1 cells.

CD4+ Th1 cells produce IFN-gamma, TNF-alpha, and IL-2. These Th1 cytokines play critical roles in both protective immunity and inflammatory responses. In this study we report that sphingosine kinase 1 (SPHK1), but not SPHK2, is highly expressed in DO11.10 Th1 cells. The expression of SPHK1 in Th1 cells requires TCR signaling and new protein synthesis. SPHK1 phosphorylates sphingosine to form sphingosine-1-phosphate. Sphingosine-1-phosphate plays important roles in inhibition of apoptosis, promotion of cell proliferation, cell migration, calcium mobilization, and activation of ERK1/2. When SPHK1 expression was knocked down by SPHK1 short interfering RNA, the production of IL-2, TNF-alpha, and IFN-gamma by Th1 cells in response to TCR stimulation was enhanced. Consistently, overexpression of dominant-negative SPHK1 increased the production of IL-2, TNF-alpha, and IFN-gamma in Th1 cells. Furthermore, overexpression of SPHK1 in Th1 and Th0 cells decreased the expression of IL-2, TNF-alpha, and IFN-gamma. Several chemokines, including Th2 chemokines CCL17 and CCL22, were up-regulated by SPHK1 short interfering RNA and down-regulated by overexpression of SPHK1. We also showed that Th2 cells themselves express CCL17 and CCL22. Finally, we conclude that SPHK1 negatively regulates the inflammatory responses of Th1 cells by inhibiting the production of proinflammatory cytokines and chemokines.

BTLA is a lymphocyte inhibitory receptor with similarities to CTLA-4 and PD-1.

During activation, T cells express receptors for receiving positive and negative costimulatory signals. Here we identify the B and T lymphocyte attenuator (BTLA), an immunoglobulin domain-containing glycoprotein with two immunoreceptor tyrosine-based inhibitory motifs. BTLA is not expressed by naive T cells, but it is induced during activation and remains expressed on T helper type 1 (T(H)1) but not T(H)2 cells. Crosslinking BTLA with antigen receptors induces its tyrosine phosphorylation and association with the Src homology domain 2 (SH2)-containing protein tyrosine phosphatases SHP-1 and SHP-2, and attenuates production of interleukin 2 (IL-2). BTLA-deficient T cells show increased proliferation, and BTLA-deficient mice have increased specific antibody responses and enhanced sensitivity to experimental autoimmune encephalomyelitis. B7x, a peripheral homolog of B7, is a ligand of BTLA. Thus, BTLA is a third inhibitory receptor on T lymphocytes with similarities to cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) and programmed death 1 (PD-1).