The Role of β-Catenin in Th1 Immune Response against Tuberculosis and Profiles of Expression in Patients with Pulmonary Tuberculosis

β-Catenin is a key molecule of canonical Wnt/β-catenin pathway. Its roles and expression profiles in T cells of tuberculosis (TB) remain unclear. The aim of this study was to explore the role of β-catenin in CD4+ T cells and its expression characteristics in patients with pulmonary tuberculosis (PTB). In this study, CD4+ T cell-specific β-catenin conditional knockout mice (β-CAT-cKO mice) were aerosol infected with Mycobacteria tuberculosis (Mtb) H37RV with wild-type mice as controls. Four weeks after infection, the mRNA expression of IFN-γ, TNF-α, and TCF-7 in the lungs of mice was measured. CD4, CD8, β-catenin, IFN-γ, and TNF-α in mononuclear cells from the lungs and spleens were measured by flow cytometry, and the pathological changes of lungs were also observed. Patients with PTB were enrolled, with blood samples collected and PBMCs isolated. The expressions of β-catenin, IFN-γ, TNF-α, and PD-1 in CD4+ and CD8+ T cells were measured by flow cytometry. Results showed a decreased frequency of and reduced IFN-γ/TNF-α mRNA expression and secretion by CD4+ T cells in the lungs of infected β-CAT-cKO mice compared with infected wild-type controls, and only slightly more inflammatory changes were observed in the lungs. β-catenin expressions in CD4+ and CD8+ T cells were significantly decreased in blood cells of patients with severe PTB compared with those in mild PTB. The stimulation of peripheral blood mononuclear cells (PBMCs) with lithium chloride (LiCl), a stimulant of β-catenin, resulted in the increase in CD4+ T cell frequency, as well as their secretion of IFN-γ and TNF-α. β-Catenin demonstrated a moderately positive correlation with PD-1 in CD4+ T cells. β-Catenin along with PD-1 and IFN-γ in CD4+ T cells had a high correlation with those in CD8+ T cells. In conclusion, β-catenin may be involved in the regulation of Th1 response and CD4+ T cell frequency in TB

Genome-Wide Analysis of the TCP Gene Family in Switchgrass (Panicum virgatum L.)

The plant-specific transcription factor TCPs play multiple roles in plant growth, development, and stress responses. However, a genome-wide analysis of TCP proteins and their roles in salt stress has not been declared in switchgrass (Panicum virgatum L.). In this study, 42 PvTCP genes (PvTCPs) were identified from the switchgrass genome and 38 members can be anchored to its chromosomes unevenly. Nine PvTCPs were predicted to be microRNA319 (miR319) targets. Furthermore, PvTCPs can be divided into three clades according to the phylogeny and conserved domains. Members in the same clade have the similar gene structure and motif localization. Although all PvTCPs were expressed in tested tissues, their expression profiles were different under normal condition. The specific expression may indicate their different roles in plant growth and development. In addition, approximately 20 cis-acting elements were detected in the promoters of PvTCPs, and 40% were related to stress response. Moreover, the expression profiles of PvTCPs under salt stress were also analyzed and 29 PvTCPs were regulated after NaCl treatment. Taken together, the PvTCP gene family was analyzed at a genome-wide level and their possible functions in salt stress, which lay the basis for further functional analysis of PvTCPs in switchgrass

Mutation of 4-coumarate: coenzyme A ligase 1 gene affects lignin biosynthesis and increases the cell wall digestibility in maize brown midrib5 mutants

Abstract Background Maize brown midrib (bm) mutants associated with impaired lignin biosynthesis are a potential source for the breed of novel germplasms with improved cell wall digestibility. The spontaneous bm5 mutants had been identified since 2008. However, the gene responsible for the bm5 locus, and the comprehensive effects of bm5 mutation on lignin biosynthesis, soluble phenolics accumulation, and cell wall degradation have yet to be elucidated. Results The bm5 locus was identified to encode a major 4-coumarate: coenzyme A ligase (Zm4CL1) through analyzing MutMap-assisted gene mapping data. Two alleles of Zm4CL1 isolated from bm5 mutants contained two transposons inserted in the first exon and the second intron, respectively, and consequently, the activities of 4CLs in the crude enzyme extracts from bm5 midribs were reduced by 51–62% compared with the wild type. Furthermore, five 4CLs were retrieved from maize genome, and Zm4CL1 was the most highly expressed one in the lignified tissues. Mutation of Zm4CL1 mainly impeded the biosynthesis of guaiacyl (G) lignins and increased the level of soluble feruloyl derivatives without impacting maize growth and development. Moreover, both neutral detergent fiber digestibility and saccharification efficiency of cell walls were significantly elevated in the bm5 mutant. Conclusions Zm4CL1 was identified as the Bm5 gene, since two independent alleles of Zm4CL1 were associated with the same mutant phenotype. Mutation of Zm4CL1 mainly affected G lignin biosynthesis and soluble feruloyl derivatives accumulation in maize lignified tissues. The reduced recalcitrance of the bm5 mutant suggests that Zm4CL1 is an elite target for cell wall engineering, and genetic manipulation of this gene will facilitate the utilization of crop straw and stover that have to be dealt with for environmental protection