Effect of miR-146a and miR-155 on cardiac xenotransplantation

Xenotransplantation: Current Challenges and Emerging Solutions

To address the ongoing shortage of organs available for replacement, xenotransplantation of hearts, corneas, skin, and kidneys has been attempted. However, a major obstacle facing xenotransplants is rejection due to a cycle of immune reactions to the graft. Both adaptive and innate immune systems contribute to this cycle, in which natural killer cells, macrophages, and T-cells play a significant role. While advancements in the field of genetic editing can circumvent some of these obstacles, biomarkers to identify and predict xenograft rejection remain to be standardized. Several T-cell markers, such as CD3, CD4, and CD8, are useful in both the diagnosis and prediction of xenograft rejection. Furthermore, an increase in the levels of various circulating DNA markers and microRNAs is also predictive of xenograft rejection. In this review, we summarize recent findings on the advancements in xenotransplantation, with a focus on pig-to-human, the role of immunity in xenograft rejection, and its biomarkers.

Trichoderma stromaticum spores induce autophagy and downregulate inflammatory mediators in human peripheral blood-derived macrophages

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T. stromaticum biocontrol agent induces autophagy, up-regulating autophagy-related genes

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T. stromaticum modulates expression of micro RNAs that control imune response

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T. stromaticum dow-nregulates expression of TLR2, TLR4, CLEC7A, NLRP3, IL-10, IL1β and IL18

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T. stromaticum modulates ROS production

Trichoderma spp. are usually considered safe and normally used as biocontrol and biofertilization. Safety for human health is evaluated by several tests that detect various effects such as allergenicity, toxicity, infectivity, and pathogenicity. However, they do not evaluate the effects of the agent upon the immune system. The aim of this study was to investigate the interaction between T. stromaticum spores and mammalian cells to assess the immunomodulatory potential of the spores of this fungus. First, mouse macrophage cell line J774 and human macrophages were exposed to fungal spores and analyzed for structural features, through scanning and transmission electron microscopy. Then, various analysis were performed in human macrophages as to their effect in some functional and molecular aspects of the immune system through immunocytochemistry, flow cytometry and gene expression assays. We demonstrated that T. stromaticum spores induces autophagy and autophagy-related genes (ATGs) and downmodulate inflammatory mediators, including ROS, NLRP3, the cytokines IL-1β, IL-18, IL-12 and IL-10, as well as TLR2, TLR4, miR-146b and miR-155, which may lead to an augmented susceptibility to pathogens. Our study shows the extension of damages the biofungicide Tricovab® can cause in the innate immune response. Further studies are necessary to elucidate other innate and adaptive immune responses and, consequently, the safety of this fungus when in contact with humans.

Evaluation Expression of miR-146a and miR-155 in Non-Small-Cell Lung Cancer Patients

Background

Non−small-cell lung cancer (NSCLC) is the major type of lung cancer. MicroRNAs (miRNAs) are novel markers and targets in cancer therapy and can act as both tumor suppressors and oncogenes and affect immune function. The aim of this study was to investigate the expression of miR146a and miR155 in linked to blood immune cell phenotypes and serum cytokines in NSCLC patients.

Methods

Thirty-three NSCLC patients and 30 healthy subjects were enrolled in this study. The allele frequencies of potential DNA polymorphisms were studied using polymerase chain reaction (PCR)–restriction fragment length polymorphism (PCR-RFLP) analysis in peripheral blood samples. Quantitative reverse transcription PCR (qRT-PCR) was used to measure the expression of miR-146a and miR-155 in peripheral blood mononuclear cells (PBMCs). Serum cytokine (IL-1β, IL-6, TNF-α, TGF-β, IL-4, IFN-γ) levels were determined by ELISA. The frequency of circulating CD3+CTLA-4+ and CD4+CD25+FOXP3+ (T regulatory cells/Treg) expression was measured by flow cytometry.

Results

miR-146a was significantly downregulated in PBMC of NSCLC patients (P ≤ 0.001). Moreover, IL-6 and TGF-β levels were elevated in NSCLC patients (P ≤ 0.001, P ≤ 0.018, respectively). CD3+ CTLA-4+ and Treg cells frequencies were higher in patients than in control subjects (P ≤ 0.0001, P ≤ 0.0001, respectively). There was a positive correlation between miR-155 and IL-1β levels (r=0.567, p ≤ 0.001) and a negative correlation between miR-146a and TGF-β levels (r=-0.376, P ≤ 0.031) in NSCLC patients. No significant differences were found in the relative expression of miR-146a and miR-155, cytokine levels or immune cell numbers according to miR-146a and miR-155 (GG/GC/CC, TT/AT/AA) genotypes. However, there was a positive correlation between miR-146a and IL-1β levels (r=0.74, P ≤ 0.009) in GG subjects and a positive correlation between miR-146a expression and CD3+CTLA4+ cell frequency (r=0.79, P ≤ 0.01) in CC genotyped subjects. Conversely, a negative correlation between miR-146a expression and Treg cell frequency (r=−0.87, P ≤ 0.05) was observed with the GG genotype. A positive correlation between miR-155 and IL-1β expression (r=0.58, p ≤ 0.009) in the TT genotype and between miR-155 expression and CD3+CTLA-4 cell frequency (r=0.75, P ≤ 0.01) was observed in the AT genotype.

Conclusions

The current data suggest that the miR-146a expression in PBMC and serum TGF-β and IL-1β levels may act as blood markers in NSCLC patients. Further study is needed to elucidate the link between immune cells and serum miR146 at early disease stages.

M2 Macrophage-Derived Exosomes Promote Angiogenesis and Growth of Pancreatic Ductal Adenocarcinoma by Targeting E2F2

Pancreatic ductal adenocarcinoma (PDAC), one of the most aggressive tumors all over the world, has a generally poor prognosis, and its progression is positively correlated with the density of blood vessels. Recently, tumor-associated macrophages (TAMs) were proven to be beneficial for angiogenesis, but their mechanism of action remains unclear. Our study indicated that M2 macrophages were positively correlated with the microvessel density (MVD) of PDAC tissues, and M2 macrophage-derived exosomes (MDEs) could promote the angiogenesis of mouse aortic endothelial cells (MAECs) in vitro. At the same time, the M2 MDEs could also promote the growth of subcutaneous tumors and increase the vascular density of mice. Moreover, we also found that miR-155-5p and miR-221-5p levels in the M2 MDEs were higher than those in M0 MDEs, and they could be transferred into MAECs, as demonstrated by RNA sequencing (RNA-seq) and qPCR analysis. Our data confirmed the interaction between TAMs and the angiogenesis of PDAC by exosomes. Additionally, targeting the exosomal miRNAs derived from TAMs might provide diagnostic and therapeutic strategies for PDAC.

Effect of miR-744 on Ameliorating Heart Allograft Rejection in BALB/c Mice Via Regulation of TNFRSF4 Expression in Regulatory T Cells

CD134 (TNFRSF4) is a member of the TNFR superfamily, which is specifically expressed on T cells. Previous studies have shown that blocking of CD134L-CD134 interaction reduces the percentage of activated T cells and prevents effector T cell-mediated graft rejection in heart transplantation. However, the role of microRNA-regulated inhibition of the CD134 signal in cardiac transplantation of T-regulatory (Treg) cells is not clear. In this study, we found microRNA 744 (miR-744) agomir administration enhanced the expression levels of miR-744 in CD4⁺CD25⁺ Treg cells from heart transplantation mice. Moreover, miR-744 agomir administration significantly enhanced the expression levels of CD62L and Ki67 in CD4⁺CD25⁺ Treg cells from heart transplantation mice and further enhanced immunosuppressive function of Treg cells following coculture with CD4⁺CD25^- T cells for different ratios. In addition, miR-744 agomir treatment significantly prolonged survival time and reduced rejection response of heart allografts in vivo, which are involved in downregulation of TNFRSF4 expression. These results provided a novel molecular mechanism of ameliorating heart allograft rejection in Treg cells, which could be used in the treatment of heart allograft rejection clinically.

Circulating miRNA-150-5p is associated with immune-mediated early β-cell loss in a humanized mouse model

BACKGROUND

Aberrant microRNA (miRNA) expression levels are associated with various graft rejections. We used our humanized mouse model with transplanted human islets to identify miRNAs in islet grafts related to xenograft rejection and circulating miRNAs associated with xenograft rejection-mediated β-cell loss.

METHODS

Diabetic immunodeficient NOD.scid mice were transplanted with human islets and subsequently achieved stable normoglycemia. Lymphocytes from NOD mice were then adoptively transferred to the humanized mice to induce human β-cell destruction. Islet graft and plasma were collected immediately once blood glucose reached >200 mg/dL. miRNAs in the islet grafts and in the plasma with or without adoptive lymphocyte transfer (ALT) were measured using NanoString nCounter® miRNA Expression Assay and qPCR.

RESULTS

A set of immune-related miRNAs was significantly increased in human islet grafts of ALT-treated mice compared to control mice. Of these miRNAs, miR-150-5p was significantly increased in the circulation of ALT-treated mice at tissue collection and the increase was a result of immune activation rather than simply the presence of lymphocytes in circulation. Furthermore, miR-150-5p was significantly increased in human islet graft and circulation prior to the development of hyperglycemia in the ALT-treated mice.

CONCLUSIONS

Our data demonstrated that immune-related miRNAs are associated with human islet xenograft rejection in mice. miR-150-5p is increased in human islet graft and in the circulation during islet xenograft rejection and β-cell destruction prior to hyperglycemia and may be an early biomarker for islet xenograft rejection.