No abstract

Accurate diagnosis of complete inactivation of tuberculosis lesions is still a challenge with respect to sputum-negative tuberculosis. RNA-sequencing was conducted to uncover potential lncRNA indicators of metabolic activity in tuberculosis lesions. Lung tissues with high metabolic activity and low metabolic activity demonstrated by fluorine-18-fluorodeoxyglucose positron emission tomography/computed tomography were collected from five sputum-negative tuberculosis patients for RNA-sequencing. Differentially-expressed mRNAs and lncRNAs were identified. Their correlations were evaluated to construct lncRNA-mRNA co-expression network, in which lncRNAs and mRNAs with high degrees were confirmed by quantitative real-time PCR using samples collected from 11 patients. Prediction efficiencies of lncRNA indicators were assessed by receiver operating characteristic curve analysis. Bioinformatics analysis was performed for potential lncRNAs. 386 mRNAs and 44 lncRNAs were identified to be differentially expressed. Differentially-expressed mRNAs in lncRNA-mRNA co-expression network were significantly associated with fibrillar collagen, platelet-derived growth factor binding, and leukocyte migration involved in inflammatory response. Seven mRNAs ( C1QB , CD68 , CCL5 , CCL19 , MMP7 , HLA-DMB , and CYBB ) and two lncRNAs ( ENST00000429730.1 and MSTRG.93125.4 ) were validated to be significantly up-regulated. The area under the curve of ENST00000429730.1 and MSTRG.93125.4 was 0.750 and 0.813, respectively. Two lncRNAs ENST00000429730.1 and MSTRG.93125.4 might be considered as potential indicators of metabolic activity in tuberculosis lesions for sputum-negative tuberculosis.

Influx of eosinophils into the lungs is typically associated with type-II responses during allergy, fungal and parasitic infections. However, we previously reported that eosinophils accumulate in lung lesions during type-I inflammatory responses to Mycobacterium tuberculosis (Mtb) in humans, macaques, and mice where they contribute to host resistance. Here we show eosinophils migrate into the lungs of macaques and mice as early as one week after Mtb-exposure. In mice this influx was CCR3 independent and instead required cell-intrinsic expression of the oxysterol-receptor GPR183, which is highly expressed on human and macaque eosinophils. Murine eosinophils interacted directly with bacilli-laden alveolar macrophages, which upregulated the oxysterol-synthesizing enzyme Ch25h, and eosinophil recruitment was impaired in Ch25h deficient mice. Our findings show that eosinophils are among the first cells from circulation to sense and respond to Mtb infection of alveolar macrophages and reveal a novel role for GPR183 in the migration of eosinophils into lung tissue.

Macrophages are key phagocytic cells and play an important role in eliminating external microorganisms and endogenous danger signals. Dysregulation in macrophage functions have been reported in patients with asthma. Zinc homeostasis is critical in maintaining macrophage functions. The solute carrier (SLC) protein SLC39A7, a Zn2+ importer, has recently been linked to asthma. However, the roles of SLC39A7 in macrophage phagocytosis are not well understood. Here we found that phagocytosis efficiency was significantly decreased in SLC39A7-knockdown THP-1 cells, however the phagocytosis capability could be reversed with zinc supplementation. SLC39A7 deficiency skewed macrophages towards alternative activation, as indicated by increased expression of M2 activation marker CD206 and decreased expression of M1 activation marker NOS2. Consistent to this result, SLC39A7knockdown cells produced reduced amounts of proinflammatory cytokines TNF-and IL-6. Furthermore, the mRNA level of receptor Clec4e previously known to be involved in phagocytosis of BCG was significantly reduced in SLC39A7 knockdown cells. Importantly, all these defects due to SLC39A7 deficiency could be reversed by zinc supplementation. Thus, zinc transporter SLC39A7 provide support for phagocytosis and classical macrophage activation.