Time-course transcriptome analysis of lungs from mice exposed to ricin by intratracheal inoculation

Spatiotemporal single-cell transcriptomic profiling reveals inflammatory cell states in a mouse model of diffuse alveolar damage

Diffuse alveolar damage (DAD) triggers neutrophilic inflammation in damaged tissues of the lung, but little is known about the distinct roles of tissue structural cells in modulating the recruitment of neutrophils to damaged areas. Here, by combining single-cell and spatial transcriptomics, and using quantitative assays, we systematically analyze inflammatory cell states in a mouse model of DAD-induced neutrophilic inflammation after aerosolized intratracheal inoculation with ricin toxin. We show that homeostatic resident fibroblasts switch to a hyper-inflammatory state, and the subsequent occurrence of a CXCL1-CXCR2 chemokine axis between activated fibroblasts (AFib) as the signal sender and neutrophils as the signal receiver triggers further neutrophil recruitment. We also identify an anatomically localized inflamed niche (characterized by a close-knit spatial intercellular contact between recruited neutrophils and AFib) in peribronchial regions that facilitate the pulmonary inflammation outbreak. Our findings identify an intricate interplay between hyper-inflammatory fibroblasts and neutrophils and provide an overarching profile of dynamically changing inflammatory microenvironments during DAD progression.

Expression of TFRC helps to improve the antineoplastic effect of Ara-C on AML cells through a targeted delivery carrier

BACKGROUND

Currently, high doses of cytarabine arabinoside (Ara-C)-based combined chemotherapy are commonly used in acute myeloid leukemia (AML) therapy, but severe adverse effects and poor suppression effects in leukemia cells limit the clinical therapeutic efficiency of Ara-C-based chemotherapy due to a lack of targeting selectivity. To improve the therapeutic effect of Ara-C in AML, here, since we confirmed that transferrin receptor 1 (TFRC) expression in AML cells was constant, we generated Ara-C@HFn by encapsulating free Ara-C into self-assembled heavy ferritin chain (HFn, the ligand of TFRC) nanocages.

RESULTS

The analysis of clinically relevant data suggested that the high expression levels of TFRC from AML cells would not decrease significantly after treatment with Ara-C. Ara-C@HFn can be efficiently internalized by leukemia cells, showing stronger cytotoxic effects in vitro and reducing the burden of leukemia in AML mice more effectively in vivo than free Ara-C. Ara-C@HFn treatment showed no acute toxicity in visceral organs of mice. Moreover, the analysis of clinically relevant data also suggested that there are several drugs (such as tamibarotene and ABT199) that would not cause significant expression down-regulation of TFRC in AML cells (after treatment).

CONCLUSION

The above results suggested that TFRC can be used as a constant and effective target for drug targeting delivery of AML cells. Thus Ara-C@HFn treatment can become a safe and efficient strategy for AML therapy by specifically delivering Ara-C to AML cells. Besides, the HFn nanocages are promising for improving antineoplastic effect of other AML-related therapy drugs that do not cause downregulated expression of TFRC in AML cells.

Csf2ra deletion attenuates acute lung injuries induced by intratracheal inoculation of aerosolized ricin in mice

Specific therapeutics are not available for acute lung injury (ALI) induced by ricin toxin (RT). Inhibiting the host immune response in the course of pulmonary ricinosis is hypothesized to be of benefit and can be achieved by impairing granulocyte-macrophage colony-stimulating factor (GM-CSF) signaling, thereby reducing the pro-inflammatory response to exogenous foreign body invasion. However, it is unknown whether mice with impaired GM-CSF signaling can survive after RT inhalation. To test this, colony stimulating factor 2 receptor alpha (Csf2ra) knockout (KO) mice that lack GM-CSF signaling and wild-type (WT) mice models of intratracheal exposure to a lethal dose (2× LD₅₀) of RT were established. Survival was greater in Csf2ra KO mice 21 days after RT inhalation compared with WT mice. Highly co-expressed genes that probably attenuated the pro-inflammatory response in the lung of Csf2ra KO mice were identified. Bioinformatics analysis revealed that transcriptome changes involved mostly inflammation-related genes after RT exposure in both Csf2ra KO mice and WT mice. However, the activity levels of pro-inflammatory pathways, such as the TNF signaling pathway and NF-κB signaling pathway, in Csf2ra KO mice were significantly decreased and the degree of neutrophil chemotaxis and recruitment inhibited after RT-exposure relative to WT mice. RT-qPCR and flow cytometry validated results of RNA-Seq analysis. This work provides potential avenues for host-directed therapeutic applications that can mitigate the severity of ALI-induced by RT.

Transcriptome Analysis of Rat Lungs Exposed to Moxa Smoke after Acute Toxicity Testing

The increasing use of moxibustion has led to a debate concerning the safety of this treatment in human patients. Inhalation of cigarette smoke induces lung inflammation and granulomas, the proliferation of alveolar epithelial cells, and other toxic effects; therefore, it is important to assess the influence of inhaled moxa smoke on the lungs. In the present study, a novel poisoning cabinet was designed and used to assess the acute toxicity of moxa smoke in rats. We evaluated pathological changes in rat lung tissue and analyzed differentially expressed genes (DEGs) using RNA-seq and transcriptomic analyses. Our results show that the maximum tolerable dose of moxa smoke was 290.036 g/m³ and LC50 was 537.65 g/m³. Compared with that of the control group, the degree of inflammatory cell infiltration in the lung tissues of group A rats (all dead group) was increased, while that in group E rats (all live group) remained unchanged. GO and KEGG enrichment analyses showed that the DEGs implicated in cell components, binding, and cancer were significantly enriched in the experimental groups compared with the profile of the control group. The expressions of MAFF, HSPA1B, HSPA1A, AOC1, and MX2 determined using quantitative real-time PCR were similar to those determined using RNA-seq, confirming the reliability of RNA-seq data. Overall, our results provide a basis for future evaluations of moxibustion safety and the development of moxibustion-based technology.