Forced expression of the non-coding RNA miR-17∼92 restores activation and function in CD28-deficient CD4+ T cells

MicroRNAs in transplant rejection: Emerging roles in immune regulation and applications

Organ transplantation is the only effective treatment for patients with end-stage organ failure. Although modern immunosuppressive protocols are very effective and improve quality of life, there is still a need for improvements to eliminate their side effects and to induce transplantation tolerance to allografts. The microRNAs (miRNAs) emerged as promising candidates for regulations of several immune functions. The most advanced research of miRNAs documented that several miRNAs form very complex regulatory networks involved in fine and precise mechanisms of multiple pathophysiological process in cells. This review describes the origin of miRNAs and their action mechanisms by which they regulate several immune and cell biology processes, highlighting the fast progress of miRNA research involved in transplant rejection, recent clinical trials, and describing prospects and possible limitations.

CD28 co-stimulation: novel insights and applications in cancer immunotherapy

Substantial progress in understanding T cell signalling, particularly with respect to T cell co-receptors such as the co-stimulatory receptor CD28, has been made in recent years. This knowledge has been instrumental in the development of innovative immunotherapies for patients with cancer, including immune checkpoint blockade antibodies, adoptive cell therapies, tumour-targeted immunostimulatory antibodies, and immunostimulatory small-molecule drugs that regulate T cell activation. Following the failed clinical trial of a CD28 superagonist antibody in 2006, targeted CD28 agonism has re-emerged as a technologically viable and clinically promising strategy for cancer immunotherapy. In this Review, we explore recent insights into the molecular functions and regulation of CD28. We describe how CD28 is central to the success of current cancer immunotherapies and examine how new questions arising from studies of CD28 as a clinical target have enhanced our understanding of its biological role and may guide the development of future therapeutic strategies in oncology.

Non-coding RNAs in cancer immunotherapy: A solution to overcome immune resistance?

With the rapid advancement in immunotherapy, cancer immune resistance has become more evident, which demands new treatment approaches to achieve greater efficacy. Non-coding RNAs (ncRNAs) are a heterogeneous group of RNAs that are not translated to proteins but instead regulate different stages of gene expression. Recent studies have increasingly supported the critical role of ncRNAs in immune cell-cancer cell cross-talk, and numerous ncRNAs have been implicated in the immune evasion of cancer cells. Cancer cells take advantage of ncRNAs to modulate several signaling pathways and upregulate the expression of immune checkpoints and anti-inflammatory mediators, thereby dampening the anti-tumor response of M1 macrophages, dendritic cells, cytotoxic T cells, and natural killer cells or potentiating the immunosuppressive properties of M2 macrophages, regulatory T cells, and myeloid-derived suppressive cells. Upregulation of immunosuppressive ncRNAs or downregulation of immunogenic ncNRAs is a major driver of resistance to immune checkpoint inhibitors, cancer vaccines, and other means of cancer immunotherapy, making ncRNAs ideal targets for treatment. In addition, ncRNAs released by cancer cells have been demonstrated to possess prognostic values for patients who undergo cancer immunotherapy. Future clinical trials are urged to consider the potential of ncRNAs in cancer immunotherapy.

T helper cells exhibit a dynamic and reversible 3'-UTR landscape

3' untranslated regions (3' UTRs) are critical elements of messenger RNAs, as they contain binding sites for RNA-binding proteins (RBPs) and microRNAs that affect various aspects of the RNA life cycle including transcript stability and cellular localization. In response to T cell receptor activation, T cells undergo massive expansion during the effector phase of the immune response and dynamically modify their 3' UTRs. Whether this serves to directly regulate the abundance of specific mRNAs or is a secondary effect of proliferation remains unclear. To study 3'-UTR dynamics in T helper cells, we investigated division-dependent alternative polyadenylation (APA). In addition, we generated 3' end UTR sequencing data from naive, activated, memory, and regulatory CD4+ T cells. 3'-UTR length changes were estimated using a nonnegative matrix factorization approach and were compared with those inferred from long-read PacBio sequencing. We found that APA events were transient and reverted after effector phase expansion. Using an orthogonal bulk RNA-seq data set, we did not find evidence of APA association with differential gene expression or transcript usage, indicating that APA has only a marginal effect on transcript abundance. 3'-UTR sequence analysis revealed conserved binding sites for T cell-relevant microRNAs and RBPs in the alternative 3' UTRs. These results indicate that poly(A) site usage could play an important role in the control of cell fate decisions and homeostasis.

Identification of extracellular vesicle microRNA signatures specifically linked to inflammatory and metabolic mechanisms in obesity-associated low type-2 asthma

RATIONALE AND OBJECTIVE

Plasma extracellular vesicles (EVs) represent a vital source of molecular information about health and disease states. Due to their heterogenous cellular sources, EVs and their cargo may predict specific pathomechanisms behind disease phenotypes. Here we aimed to utilize EV microRNA (miRNA) signatures to gain new insights into underlying molecular mechanisms of obesity-associated low type-2 asthma.

METHODS

Obese low type-2 asthma (OA) and non-obese low type-2 asthma (NOA) patients were selected from an asthma cohort conjointly with healthy controls. Plasma EVs were isolated and characterised by nanoparticle tracking analysis. EV-associated small RNAs were extracted, sequenced and bioinformatically analysed.

RESULTS

Based on EV miRNA expression profiles, a clear distinction between the three study groups could be established using a principal component analysis. Integrative pathway analysis of potential target genes of the differentially expressed miRNAs revealed inflammatory cytokines (e.g., interleukin-6, transforming growth factor-beta, interferons) and metabolic factors (e.g., insulin, leptin) signalling pathways to be specifically associated with OA. The miR-17-92 and miR-106a-363 clusters were significantly enriched only in OA. These miRNA clusters exhibited discrete bivariate correlations with several key laboratory (e.g., C-reactive protein) and lung function parameters. Plasma EV miRNA signatures mirrored blood-derived CD4+ T-cell transcriptome data, but achieved an even higher sensitivity in identifying specifically affected biological pathways.

CONCLUSION

The identified plasma EV miRNA signatures and particularly the miR-17-92 and -106a-363 clusters were capable to disentangle specific mechanisms of the obesity-associated low type-2 asthma phenotype, which may serve as basis for stratified treatment development.

Leveraging microRNAs for cellular therapy

Owing to Karl Landsteiner's discovery of blood groups, blood transfusions became safe cellular therapies in the early 1900s. Since then, cellular therapy made great advances from transfusions with unmodified cells to today's commercially available chimeric antigen receptor (CAR) T cells requiring complex manufacturing. Modern cellular therapy products can be improved using basic knowledge of cell biology and molecular genetics. Emerging genome engineering tools are becoming ever more versatile and precise and thus catalyze rapid progress towards programmable therapeutic cells that compute input and respond with defined output. Despite a large body of literature describing important functions of non-coding RNAs including microRNAs (miRNAs), the vast majority of cell engineering efforts focuses on proteins. However, miRNAs form an important layer of posttranscriptional regulation of gene expression. Here, we highlight examples of how miRNAs can successfully be incorporated into engineered cellular therapies.