MicroRNA-155 may affect allograft survival by regulating the expression of suppressor of cytokine signaling 1

MiR-125b-5p modulates the function of regulatory T cells in tumor microenvironment by targeting TNFR2

BACKGROUND

Tumor necrosis factor receptor type 2 (TNFR2) is primarily expressed by CD4⁺FoxP3⁺ regulatory T cells (Tregs), especially those present in tumor microenvironment. There is compelling evidence that TNFR2 plays a crucial role in the activation, expansion, and phenotypic stability of Tregs and promotes tumor immune evasion. Understanding of epigenetic regulation of TNFR2 expression in Tregs may help device a novel strategy in cancer immunotherapy.

METHODS

MiR-125b-5p-overexpressing or knockdown murine CD4 T cells and Tregs were constructed, and the effect of miR-125b-5p on Tregs proliferation, suppressive function and TNFR2 expression were examined. In vivo antitumor efficacy of Ago-125b-5p (miR-125b-5p agomir) was evaluated in MC38 tumor bearing mice, and tumor-infiltrating Tregs and CD8⁺ cytotoxic T lymphocytes (CTLs) were analyzed. RNA-seq analysis was applied to reveal the genes and signaling pathways regulated by miR-125b-5p in Tregs.

RESULTS

In this study, we found that TNFR2 was a direct target of miR-125b-5p. Overexpression of miR-125b-5p decreased the proportion of Tregs and their expression of TNFR2 and consequently inhibited its proliferation and suppressive function by regulating the metabolism-related signaling pathways. Moreover, in colon cancer bearing mice, the administration of Ago-125b-5p markedly inhibited the tumor growth, which was associated with reduction of Tregs and increase of IFNγ⁺CD8⁺ T cells in tumor environment. Furthermore, in human colon adenocarcinoma patients, we verified that miR-125b-5p expression was downregulated, and low levels of miR-125b-5p were associated with poor prognosis. Interestingly, the expression of miR-125b-5p and TNFR2 were negatively correlated.

CONCLUSIONS

Our study for the first time found that the expression of TNFR2 by Tregs was regulated by miR-125b-5p. Our results showed that miR-125b-5p had the capacity to inhibit the expression of TNFR2 and immunosuppressive activity of Tregs and consequently enhanced the antitumor efficacy. This property of miR-125b-5p may be therapeutically harnessed in the treatment of human cancers.

Signaling pathways modulated by miRNAs in breast cancer angiogenesis and new therapeutics

MicroRNAs (miRNAs) act as oncogenes or tumor suppressors by suppressing the expression of target genes, some of which are engaged in angiogenic signaling pathways directly or indirectly. Tumor development and metastasis are dependent on angiogenesis, and it is the main reason for the poor prognosis of cancer patients. New blood vessels are formed from pre-existing vessels when angiogenesis occurs. Thus, it is essential to develop primary tumors and the spread of cancer to surrounding tissues. MicroRNAs (miRNAs) are small noncoding RNAs involved in various biological processes. They can bind to the 3'-UTR of their target genes and prevent them from expressing. MiRNAs control the activity of endothelial cells (ECs) through altering many biological pathways, which plays a key role in cancer progression and angiogenesis. Recent findings revealed that tumor-derived extracellular vesicles participated directly in the control of tumor angiogenesis by delivering miRNAs to ECs. miRNAs recently show great promise in cancer therapies to inhibit angiogenesis. In this study, we showed the miRNA-regulated signaling pathways in tumor angiogenesis with highlighting the anti-angiogenic therapy response and miRNA delivery methods that have been used to inhibit angiogenesis in both in vivo and in vitro studies.

Breast Cancer Drug Resistance: Overcoming the Challenge by Capitalizing on MicroRNA and Tumor Microenvironment Interplay

The clinical management of breast cancer reaches new frontiers every day. However, the number of drug resistant cases is still high, and, currently, this constitutes one of the major challenges that cancer research has to face. For instance, 50% of women affected with HER2 positive breast cancer presents or acquires resistance to trastuzumab. Moreover, for patients affected with triple negative breast cancer, standard chemotherapy is still the fist-line therapy, and often patients become resistant to treatments. Tumor microenvironment plays a crucial role in this context. Indeed, cancer-associated stromal cells deliver oncogenic cues to the tumor and vice versa to escape exogenous insults. It is well known that microRNAs are among the molecules exploited in this aberrant crosstalk. Indeed, microRNAs play a crucial function both in the induction of pro-tumoral traits in stromal cells and in the stroma-mediated fueling of tumor aggressiveness. Here, we summarize the most recent literature regarding the involvement of miRNAs in the crosstalk between tumor and stromal cells and their capability to modulate tumor microenvironment characteristics. All up-to-date findings suggest that microRNAs in the TME could serve both to reverse malignant phenotype of stromal cells, modulating response to therapy, and as predictive/prognostic biomarkers.

Nanotechnology, in silico and endocrine-based strategy for delivering paclitaxel and miRNA: Prospects for the therapeutic management of breast cancer

Breast cancer is one of the most prevalent and reoccurring cancers and the second most common reason of death in women. Despite advancements in therapeutic strategies for breast cancer, early tumor recurrence and metastasis in patients indicate resistance to chemotherapeutic medicines, such as paclitaxel due to the abnormal expression of ER and EGF2 in breast cancer cells. Therefore, the development of alternatives to paclitaxel is urgently needed to overcome challenges involving drug resistance. An increasing number of studies has revealed miRNAs as novel natural alternative substances that play a crucial role in regulating several physiological processes and have a close, adverse association with several diseases, including breast cancer. Due to the therapeutic potential of miRNA and paclitaxel in cancer research, the current review focuses on the differential roles of various miRNAs in breast cancer development and treatment. miRNA delivery to a specific target site, the development of paclitaxel and miRNA formulations, and nanotechnological strategies for the delivery of nanopaclitaxel in the management of breast cancer are discussed. These strategies involve improving the cellular uptake and bioavailability and reducing the toxicity of free paclitaxel to achieve accumulation tumor site. Furthermore, a molecular docking study was performed to ascertain the enhanced anticancer activity of the nanoformulation of ANG1005 and Abraxane. An in silico analysis revealed that ANG1005 and Abraxane nanoformulations have superior and significantly enhanced interactions with the proteins α-tubulin and Bcl-2. Therefore, ANG1005 and Abraxane may be more suitable in the therapeutic management of breast cancer than the existing free paclitaxel. miRNAs can revert abnormal gene expression to normalcy; since miRNAs serve as tumor suppressors. Therefore, restoration of particular miRNAs levels as a replacement therapy may be an effective endocrine potential strategy for treating ER positive/ negative breast cancers.

microRNA-142-mediated repression of phosphodiesterase 3B critically regulates peripheral immune tolerance

Tregs play a fundamental role in immune tolerance via control of self-reactive effector T cells (Teffs). This function is dependent on maintenance of a high intracellular cAMP concentration. A number of microRNAs are implicated in the maintenance of Tregs. In this study, we demonstrate that peripheral immune tolerance is critically dependent on posttranscriptional repression of the cAMP-hydrolyzing enzyme phosphodiesterase-3b (Pde3b) by microRNA-142-5p (miR-142-5p). In this manner, miR-142-5p acts as an immunometabolic regulator of intracellular cAMP, controlling Treg suppressive function. Mir142 was associated with a super enhancer bound by the Treg lineage–determining transcription factor forkhead box P3 (FOXP3), and Treg-specific deletion of miR-142 in mice (Treg^Δ142) resulted in spontaneous, lethal, multisystem autoimmunity, despite preserved numbers of phenotypically normal Tregs. Pharmacological inhibition and genetic ablation of PDE3B prevented autoimmune disease and reversed the impaired suppressive function of Tregs in Treg^Δ142 animals. These findings reveal a critical molecular switch, specifying Treg function through the modulation of a highly conserved, cell-intrinsic metabolic pathway. Modulation of this pathway has direct relevance to the pathogenesis and treatment of autoimmunity and cancer.

Effects of MicroRNA on Regulatory T Cells and Implications for Adoptive Cellular Therapy to Ameliorate Graft-versus-Host Disease

Regulatory T cells (Tregs) are key mediators of the immune system. MicroRNAs (miRNAs) are a family of ~22 nucleotide non-coding RNAs that are processed from longer precursors by the RNases Drosha and Dicer. miRNA regulates protein expression posttranscriptionally through mRNA destabilization or translational silencing. A critical role for miRNA in Treg function was initially discovered when both Dicer and Drosha knockout (KO) mice were found to develop a fatal autoimmune disease phenotypically similar to Foxp3 KO mice.

MicroRNAs in Breast Cancer: Diagnostic and Therapeutic Potential

MicroRNAs (miRNAs) are a large family of small, approximately 20-22 nucleotide, noncoding RNAs that regulate the expression of target genes, at the post-transcriptional level. miRNAs are involved in virtually diverse biological processes and play crucial roles in cellular processes, such as cell differentiation, proliferation, and apoptosis. Accumulating lines of evidence have indicated that miRNAs play important roles in the maintenance of biological homeostasis and that aberrant expression levels of miRNAs are associated with the onset of many diseases, including cancer. It is possible that the diverse roles that miRNAs play, have potential to provide valuable information in a clinical setting, demonstrating the potential to act as both screening tools for the stratification of high-risk patients, while informing the treatment decision-making process. Increasing evidence suggests that some miRNAs may even provide assistance in the diagnosis of patients with breast cancer. In addition, miRNAs may themselves be considered therapeutic targets, with inhibition or reintroduction of a particular miRNA capable of inducing a response in-vivo. This chapter discusses the role of miRNAs as oncogenes and tumor suppressors in breast cancer development and metastasis . It focuses on miRNAs that have prognostic, diagnostic, or predictive potential in breast cancer as well as the possible challenges in the translation of such observations to the clinic.

Expression Profile of MicroRNA Biogenesis Components in Renal Transplant Patients

BACKGROUND

MicroRNAs (miRNAs) and the miRNA biogenesis components are potential biomarkers of some prevalent diseases, such as cancer and diabetes. In light of this information, we aimed to investigate the expression profiles of miRNA biogenesis components in renal transplant patients before and after transplantation and how these profiles are related to immunosuppressive treatment and clinical outcomes of these patients.

METHODS

In this study, gene and protein expression profiles of Dicer, Drosha, Pasha (DGCR8), Exportin5 (XPO5), and Argonaute2 (AGO2) in peripheral blood mononuclear cells (PBMCs) of renal transplant patients were evaluated by means of real-time quantitative polymerase chain reaction and Western blot methods before and 3 months after transplantation. Patients who had transplant procedures for the first time were included in the study.

RESULTS

Gene expressions were significantly reduced after transplantation. The reduction rate of expressions in 1 patient undergoing chronic rejection was higher. In addition, in patients under everolimus treatment, gene expression of Dicer did not change and gene expression of AGO2 increased. Dicer, Drosha, DGCR8, and AGO2 protein expressions were reduced in all patients, but no change was observed in XPO5 protein expression in nonrejecting patients. Interestingly, in the patient undergoing chronic rejection, protein expression profiles other than Dicer were distinctive from nonrejecting patients. However, XPO5 protein expression was higher in that patient.

CONCLUSIONS

Our study shows the importance of the global effect of immunosuppressive treatment on the miRNA biogenesis pathway. miRNA biogenesis components are potential biomarkers indicative of graft outcome and pharmacologic target molecules.

Macrophage micro-RNA-155 promotes lipopolysaccharide-induced acute lung injury in mice and rats

Micro-RNA (miR)-155 is a novel gene regulator with important roles in inflammation. Herein, our study aimed to explore the role of miR-155 in LPS-induced acute lung injury(ALI). ALI in mice was induced by intratracheally delivered LPS. Loss-of-function experiments performed on miR-155 knockout mice showed that miR-155 gene inactivation protected mice from LPS-induced ALI, as manifested by preserved lung permeability and reduced lung inflammation compared with wild-type controls. Bone marrow transplantation experiments identified leukocytes, but not lung parenchymal-derived miR-155-promoted acute lung inflammation. Real-time PCR analysis showed that the expression of miR-155 in lung tissue was greatly elevated in wild-type mice after LPS stimulation. In situ hybridization showed that miR-155 was mainly expressed in alveolar macrophages. In vitro experiments performed in isolated alveolar macrophages and polarized bone marrow-derived macrophages confirmed that miR-155 expression in macrophages was increased in response to LPS stimulation. Conversely, miR-155 gain-of-function in alveolar macrophages remarkably exaggerated LPS-induced acute lung injury. Molecular studies identified the inflammation repressor suppressor of cytokine signaling (SOCS-1) as the downstream target of miR-155. By binding to the 3'-UTR of the SOCS-1 mRNA, miR-155 downregulated SOCS-1 expression, thus, permitting the inflammatory response during lung injury. Finally, we generated a novel miR-155 knockout rat strain and showed that the proinflammatory role of miR-155 was conserved in rats. Our study identified miR-155 as a proinflammatory factor after LPS stimulation, and alveolar macrophages-derived miR-155 has an important role in LPS-induced ALI.

Elevated miR-155 expression induces immunosuppression via CD39(+) regulatory T-cells in sepsis patient

BACKGROUND

An altered microRNA profile exists in many infectious diseases, including sepsis. CD39(+) regulatory T-cells (Tregs) have a remarkable immunosuppressive effect and play an important role in the regulation of immune balance in sepsis. However, the correlation between microRNA changes and the ratio of CD39(+) Tregs in sepsis patients has not yet been reported. The altered microRNA expression profile in sepsis patients was analyzed in this study. Moreover, the correlation between microRNAs and disease severity and prognosis was investigated. Furthermore, the correlation between microRNAs and the percentage of peripheral blood CD39(+) Tregs was investigated and further verified in an animal model.

METHODS

Sixty sepsis patients and 30 healthy controls were included. The difference in microRNA expression was investigated by microRNA microarray and was further confirmed by real-time quantitative PCR. The correlations between microRNA changes and the Sepsis-related Organ Failure Assessment (SOFA) score, severity of sepsis, and survival were analyzed. The percentage CD39(+) Tregs in the peripheral blood of sepsis patients was measured by flow cytometry. The correlation between microRNAs and the percentage CD39(+) Tregs was analyzed and further confirmed in a mouse sepsis model.

RESULTS

Compared to healthy controls, sepsis patients exhibited a significantly elevated microRNA-155 (miR-155) level (p < 0.05), which was positively related to a higher SOFA score (r = 0.641, p < 0.05) and a greater severity of sepsis. The area under the receiver operating characteristic curve of miR-155 used for the prediction of 28-day survival was 0.763, with a cut-off point of 2.47. Patients with a miR-155 level >2.47 had a lower 28-day survival (p < 0.05). The miR-155 level of patients was proportional to the percentage of CD39(+) Tregs (r = 0.637, p < 0.05). After transfection with miR-155 inhibitor, the ratio of CD39(+) Tregs in mice with sepsis was significantly reduced (p < 0.05).

CONCLUSIONS

A higher level of miR-155 indicated a more severe condition and poorer prognosis in sepsis patients. The possible underlying mechanism could be that miR-155 induces an increased percentage of CD39(+) Tregs and thus immunosuppression.

Clinical significance of intragraft miR-122 and -155 expression after liver transplantation

AIM

Recurrent hepatitis C (RHC) and acute cellular rejection (AR) remain critical problems following liver transplantation (LT) in hepatitis C virus (HCV) positive recipients because of the similar clinical features. Discrimination between these conditions can be problematic, and adjunctive biomarkers would be useful to discriminate these processes. The aim of our study was to investigate the possibility of the intragraft miR-122 and -155 expression as new biomarkers after LT.

METHODS

A total of 29 HCV positive recipients were enrolled in this study. Intragraft expressions of miR-122 and -155 were studied between RHC predominant (n = 17) and AR predominant cases (n = 12) using quantitative reverse transcription polymerase chain reaction. Furthermore, we investigated the correlations between these expression levels and clinical serum parameters.

RESULTS

Intragraft miR-122 expression had a good correlation with serum alkaline phosphatase (P = 0.02), but it was not correlated with the serum HCV viral load. The expression levels of miR-122 in the AR group were significantly higher than those in the RHC group (P = 0.0006) and, inversely, the expression levels of miR-155 in the AR group were significantly lower than those in the RHC group (P = 0.01).

CONCLUSION

Our study emphasizes a useful pattern of miR-122 and -155 as ancillary markers to discriminate AR predominant cases from RHC in HCV positive patients after LT.

Staphylococcal enterotoxin B-induced microRNA-155 targets SOCS1 to promote acute inflammatory lung injury

Staphylococcal enterotoxin B (SEB) causes food poisoning in humans. It is considered a biological weapon, and inhalation can trigger lung injury and sometimes respiratory failure. Being a superantigen, SEB initiates an exaggerated inflammatory response. While the role of microRNAs (miRNAs) in immune cell activation is getting increasing recognition, their role in the regulation of inflammatory disease induced by SEB has not been studied. In this investigation, we demonstrate that exposure to SEB by inhalation results in acute inflammatory lung injury accompanied by an altered miRNA expression profile in lung-infiltrating cells. Among the miRNAs that were significantly elevated, miR-155 was the most overexpressed. Interestingly, miR-155(-/-) mice were protected from SEB-mediated inflammation and lung injury. Further studies revealed a functional link between SEB-induced miR-155 and proinflammatory cytokine gamma interferon (IFN-γ). Through the use of bioinformatics tools, suppressor of cytokine signaling 1 (SOCS1), a negative regulator of IFN-γ, was identified as a potential target of miR-155. While miR-155(-/-) mice displayed increased expression of Socs1, the overexpression of miR-155 led to its suppression, thereby enhancing IFN-γ levels. Additionally, the inhibition of miR-155 resulted in restored Socs1expression. Together, our data demonstrate an important role for miR-155 in promoting SEB-mediated inflammation in the lungs through Socs1 suppression and suggest that miR-155 may be an important target in preventing SEB-mediated inflammation and tissue injury.

Toll like receptor (TLR)-induced differential expression of microRNAs (MiRs) promotes proper immune response against infections: a systematic review

Toll like receptors (TLRs) are one of the major families of pattern recognition receptors (PRRs). MicroRNAs (MiRs) are small noncoding RNAs with regulatory effects on biological process, and it has been recently shown that they can control inflammatory process and the response to an infection by modulating the function of TLRs. In this study, we designed a systematic review to clarify the reciprocal interaction between TLRs and MiRs, in order to identify possible future therapeutic targets and strategies. On the one hand, TLRs stimulation can change expression level of miRs in various ways, which can lead to modulating their effects. On the other hand, MiRs also influence the expression of TLRs and the intensity of the inflammatory reaction. We therefore conclude that the interaction between MiRs and TLRs is a key regulator of innate immune system. Investigations discovering therapeutic approaches by manipulation of miRs expression level may open a new approach for the treatment of inflammatory diseases.

The pits and pearls in translating operational tolerance biomarkers into clinical practice

PURPOSE OF REVIEW

This review highlights the importance and the role of key biomarker studies in liver and kidney transplant tolerance, discusses the most recent findings with respect to organ-type and cell-type specificity in blood and tissue, and points out the novel research directions in the field of immunological tolerance that involve both adult and pediatric recipients.

RECENT FINDINGS

Recent studies indicate that biomarkers for solid organ transplant tolerance are distinct with respect to organ type and cell type, suggesting distinct tolerogenic mechanisms for different organs. In both liver and kidney transplant tolerant recipients, novel cellular mechanisms have been proposed for natural killer cells, B cells, and dendritic cells in the maintenance of stable operational tolerance.

SUMMARY

Major advances have been made with respect to the understanding of mechanisms and the process of discovery and early validation of peripheral blood biomarkers for operational transplant tolerance both in kidney and liver transplantation. These studies have shed light on the findings that these tolerance mechanisms may be organ specific, as the peripheral blood transcriptional profiling attempts by microarrays and PCR reveal distinct differences and suggest roles for specific cell types. Although these studies are mostly in adults and limited in children, the first tolerance gene signature for pediatric liver transplant tolerance suggests that there are common mechanisms, yet distinct peripheral biomarkers across age. Prospective trials and organ integrative studies are now needed to further develop these biomarkers for future clinical application in addition to expanding novel approaches such as the investigation of miRNAs to better understand the tolerance mechanisms.

The role of microRNAs in breast cancer migration, invasion and metastasis

MicroRNAs (miRNAs) are a major class of small, noncoding RNA molecules that regulate gene expression by targeting mRNAs to trigger either translational repression or mRNA degradation. They have recently been more widely investigated due to their potential role as targets for cancer therapy. Many miRNAs have been implicated in several human cancers, including breast cancer. miRNAs are known to regulate cell cycle and development, and thus may serve as useful targets for exploration in anticancer therapeutics. The link between altered miRNA signatures and breast cancer development and metastasis can be observed either through the loss of tumor suppressor miRNAs, such as let-7s, miR-30a/31/34a/125s/200s/203/205/206/342 or the overexpression of oncogenic miRNAs, such as miR-10b/21/135a/155/221/222/224/373/520c in breast cancer cells. Some of these miRNAs have also been validated in tumor specimens of breast cancer patients, underscoring their potential roles in diagnostics, as well as targets for novel therapeutics for breast cancer. In this review article, we will provide an overview and update of our current understanding of the mode of action of several of these well characterized miRNAs in breast cancer models. Therefore, better understanding of the gene networks orchestrated by these miRNAs may help exploit the full potential of miRNAs in regards to cancer diagnosis, treatment, and therapeutics.

Clinical significance of microRNA-155 expression in human breast cancer

BACKGROUND

The aim of this study is to investigate clinical significance of miR-155 expression in breast cancer.

METHODS

TaqMan real-time RT-PCR was performed to detect miR-155 expression in breast cancer tissues. The correlation of miR-155 expression with clinicopathological factors and prognosis of breast cancer patients was analyzed. Then, the prognostic value of miR-155 expression was analyzed by univariate and multivariate analyses. Moreover, the effect of miR-155 expression on phenotypes of breast cancer cell was determined by antisense technology.

RESULTS

The relative expression of miR-155 was significantly higher in breast cancer tissues than in corresponding nontumor tissues. High miR-155 expression was correlated with higher tumor grade, advanced tumor stage and lymph node metastasis (P = 0.012, 0.001, and 0.003, respectively). Kaplan-Meier survival analysis indicated that the disease-free and overall survival rates of high miR-155 group were significantly lower than those of low miR-155 group (P = 0.038 and 0.029, respectively). Multivariate analysis showed that high miR-155 expression was a poor prognostic factor (P = 0.009). Furthermore, antisense targeting miR-155 could inhibit growth, induce cell arrest in G(0) /G(1) phase, enhance apoptosis, and increase radiosensitivity in breast cancer cells.

CONCLUSIONS

MiR-155 expression might be an independent prognostic factor and a therapeutic target for human breast cancer.