IFITM6 expression is increased in macrophages of tumor-bearing mice

Topical Application of Temperature-Sensitive Gel Containing Caerin 1.1 and 1.9 Peptides on TC-1 Tumour-Bearing Mice Induced High-Level Immune Response in the Tumour Microenvironment

The development of topical cream drugs that increase the immune activation of tumour-infiltrating lymphocytes against tumour and chronic viral infection-associated lesions is of great immunotherapeutic significance. This study demonstrates that the topical application of a temperature-sensitive gel containing caerin 1.1 and 1.9 peptides reduces nearly 50% of the tumour weight of HPV16 E6/E7-transformed TC-1 tumour-bearing mice via improving the tumour microenvironment. Confocal microscopy confirms the time-dependent penetration of caerin 1.9 through the epidermal layer of the ear skin structure of mice. Single-cell transcriptomic analysis shows that the caerin 1.1/1.9 gel expands the populations with high immune activation level and largely stimulates the pro-inflammatory activity of NK and dendritic cells. Closely associated with INFα response, Cebpb seems to play a key role in altering the function of all Arg1^hi macrophages in the caerin group. In addition, the caerin gel treatment recruits almost two-fold more activated CD8⁺ T cells to the TME, relative to the untreated tumour, which shows a synergistic effect derived from the regulation of S1pr1, Ccr7, Ms4a4b and Gimap family expression. The TMT10plex-labelling proteomic quantification further demonstrates the activation of interferon-alpha/beta secretion and response to cytokine stimulus by the caerin gel, while the protein contents of several key regulators were elevated by more than 30%, such as Cd5l, Gzma, Ifit1, Irf9 and Stat1. Computational integration of the proteome with the single-cell transcriptome consistently suggested greater activation of NK and T cells with the topical application of caerin peptide gel.

Intratumoral injection of caerin 1.1 and 1.9 peptides increases the efficacy of vaccinated TC-1 tumor-bearing mice with PD-1 blockade by modulating macrophage heterogeneity and the activation of CD8+ T cells in the tumor microenvironment

OBJECTIVES

Developing a vaccine formula that alters the tumor-infiltrating lymphocytes to be more immune active against a tumor is key to the improvement of clinical responses to immunotherapy. Here, we demonstrate that, in conjunction with E7 antigen-specific immunotherapy, and IL-10 and PD-1 blockade, intratumoral administration of caerin 1.1/1.9 peptides improves TC-1 tumor microenvironment (TME) to be more immune active than injection of a control peptide.

METHODS

We compared the survival time of vaccinated TC-1 tumor-bearing mice with PD-1 and IL-10 blockade, in combination with a further injection of caerin 1.1/1.9 or control peptides. The tumor-infiltrating haematopoietic cells were examined by flow cytometry. Single-cell transcriptomics and proteomics were used to quantify changes in cellular activity across different cell types within the TME.

RESULTS

The injection of caerin 1.1/1.9 increased the efficacy of vaccinated TC-1 tumor-bearing mice with anti-PD-1 treatment and largely expanded the populations of macrophages and NK cells with higher immune activation level, while reducing immunosuppressive macrophages. More activated CD8+ T cells were induced with higher populations of memory and effector-memory CD8+ T subsets. Computational integration of the proteome with the single-cell transcriptome supported activation of Stat1-modulated apoptosis and significant reduction in immune-suppressive B-cell function following caerin 1.1 and 1.9 treatment.

CONCLUSIONS

Caerin 1.1/1.9-containing treatment results in improved antitumor responses. Harnessing the novel candidate genes preferentially enriched in the immune active cell populations may allow further exploration of distinct macrophages, T cells and their functions in TC-1 tumors.

Unveiling the long non-coding RNA profile of porcine reproductive and respiratory syndrome virus-infected porcine alveolar macrophages

Background

Long noncoding RNA (lncRNA) is highly associated with inflammatory response and virus-induced interferon production. By far the majority of studies have focused on the immune-related lncRNAs of mice and humans, but the function of lncRNAs in porcine immune cells are poorly understood. Porcine reproductive and respiratory syndrome virus (PRRSV) impairs local immune responses in the lungs of nursery and growing pigs, whereas the virus triggers the inflammatory responses. Porcine alveolar macrophage (PAM) is the primary target cell of PRRSV, thus PRRSV is used as an in vitro model of inflammation. Here, we profiled lncRNA and mRNA repertories from PRRSV-infected PAMs to explore the underlying mechanism of porcine lncRNAs in regulating host immune responses.

Results

In this study, a total of 350 annotated lncRNAs and 1792 novel lncRNAs in PAMs were identified through RNA-seq analysis. Among them 86 differentially expressed (DE) lncRNAs and 406 DE protein-coding mRNAs were identified upon PRRSV incubation. GO category and KEGG pathway enrichment analyses revealed that these DE lncRNAs and mRNAs were mainly involved in inflammation- and pathogen infection-induced pathways. The results of dynamic correlated expression networks between lncRNAs and their predicted target genes uncovered that numerous lncRNAs, such as XLOC-022175, XLOC-019295, and XLOC-017089, were correlated with innate immune genes. Further analysis validated that these three lncRNAs were positively correlated with their predicted target genes including CXCL2, IFI6, and CD163. This study suggests that porcine lncRNAs affect immune responses against PRRSV infection through regulating their target genes in PAMs.

Conclusion

This study provides both transcriptomic and epigenetic status of porcine macrophages. In response to PRRSV infection, comprehensive DE lncRNAs and mRNAs were profiled from PAMs. Co-expression analysis demonstrated that lncRNAs are emerging as the important modulators of immune gene activities through their critical influence upon PRRSV infection in porcine macrophages.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07482-9.

The IFITM protein family in adaptive immunity

Interferon‐inducible transmembrane (IFITM) proteins are a family of small homologous proteins, localized in the plasma and endolysosomal membranes, which confer cellular resistance to many viruses. In addition, several distinct functions have been associated with different IFITM family members, including germ cell specification (IFITM1–IFITM3), osteoblast function and bone mineralization (IFITM5) and immune functions (IFITM1–3, IFITM6). IFITM1–3 are expressed by T cells and recent experiments have shown that the IFITM proteins are directly involved in adaptive immunity and that they regulate CD4⁺ T helper cell differentiation in a T‐cell‐intrinsic manner. Here we review the role of the IFITM proteins in T‐cell differentiation and function.

A Role for IFITM Proteins in Restriction of Mycobacterium tuberculosis Infection

The interferon (IFN)-induced transmembrane (IFITM) proteins are critical mediators of the host antiviral response. Here, we expand the role of IFITM proteins to host defense against intracellular bacterial infection by demonstrating that they restrict Mycobacterium tuberculosis (MTb) intracellular growth. Simultaneous knockdown of IFITM1, IFITM2, and IFITM3 by RNAi significantly enhances MTb growth in human monocytic and alveolar/epithelial cells, whereas individual overexpression of each IFITM impairs MTb growth in these cell types. Furthermore, MTb infection, Toll-like receptor 2 and 4 ligands, and several proinflammatory cytokines induce IFITM1–3 gene expression in human myeloid cells. We find that IFITM3 co-localizes with early and, in particular, late MTb phagosomes, and overexpression of IFITM3 enhances endosomal acidification in MTb-infected monocytic cells. These findings provide evidence that the antiviral IFITMs participate in the restriction of mycobacterial growth, and they implicate IFITM-mediated endosomal maturation in its antimycobacterial activity.

Evolutionary dynamics of the interferon-induced transmembrane gene family in vertebrates

Vertebrate interferon-induced transmembrane (IFITM) genes have been demonstrated to have extensive and diverse functions, playing important roles in the evolution of vertebrates. Despite observance of their functionality, the evolutionary dynamics of this gene family are complex and currently unknown. Here, we performed detailed evolutionary analyses to unravel the evolutionary history of the vertebrate IFITM family. A total of 174 IFITM orthologous genes and 112 pseudogenes were identified from 27 vertebrate genome sequences. The vertebrate IFITM family can be divided into immunity-related IFITM (IR-IFITM), IFITM5 and IFITM10 sub-families in phylogeny, implying origins from three different progenitors. In general, vertebrate IFITM genes are located in two loci, one containing the IFITM10 gene, and the other locus containing IFITM5 and various numbers of IR-IFITM genes. Conservation of evolutionary synteny was observed in these IFITM genes. Significant functional divergence was detected among the three IFITM sub-families. No gene duplication or positive selection was found in IFITM5 sub-family, implying the functional conservation of IFITM5 in vertebrate evolution, which is involved in bone formation. No IFITM5 locus was identified in the marmoset genome, suggesting a potential association with the tiny size of this monkey. The IFITM10 sub-family was divided into two groups: aquatic and terrestrial types. Functional divergence was detected between the two groups, and five IFITM10-like genes from frog were dispersed into the two groups. Both gene duplication and positive selection were observed in aquatic vertebrate IFITM10-like genes, indicating that IFITM10 might be associated with the adaptation to aquatic environments. A large number of lineage- and species-specific gene duplications were observed in IR-IFITM sub-family and positive selection was detected in IR-IFITM of primates and rodents. Because primates have experienced a long history of viral infection, such rapid expansion and positive selection suggests that the evolution of primate IR-IFITM genes is associated with broad-spectrum antiviral activity.