Project description:MicroRNAs (miRNAs) are small non-coding molecules targeting messenger RNAs and inhibiting protein translation. Regulated by dynamic micro-environmental cues, miRNAs in turn modulate key biological processes, including cell growth and development, energy utilization and homeostasis. In particular, miRNAs control the differentiation, survival and activation of both CD4+ T conventional (Tconv) and CD4+ T regulatory (Treg) cells, key players of the adaptive immunity; in particular, miRNA-mediated gene expression regulation contributes to the physiological response of those cells to infections and the pathological loss of immune homeostasis in autoimmunity. Upon T cell receptor (TCR) stimulation, Treg cells release a fingerprint of miRNAs in association with extracellular vesicles (EVs), which is specific and significantly different from that released by Tconv cell counterpart (GSE183713). In this study, we have highlithed how Treg-cell derived EVs, and their miRNA content, are able to block the proliferation and activation of Tconv cells, demonstrating a strong tolerogenic function.
Project description:We investigated the therapeutic effect of the extracellular vesicles secreted by glial progenitor cells (GPC-EV) derived from human induced pluripotent stem cell in a traumatic brain injury model. The injury was modeled using the dosed concussion to the open brain method. The male Wistar rats were performed traumatic brain injury (TBI), and after 24 hours animals were randomly divided into two groups: group 1 — rats with intranasal administration of PBS (control), and group 2 — rats with similar administration of extracellular visicles (EV) derived from glial progenitor cells. miRNA PCR analysis of brain tissues ( cortex, striatum, hippocampus) were performed on postoperative day 7 to investigate miRNA associated with apoptosis, and inflammation.
Project description:MicroRNAs (miRNAs) are small non-coding molecules targeting messenger RNAs and inhibiting protein translation. Regulated by dynamic micro-environmental cues, miRNAs in turn modulate key biological processes, including cell growth and development, energy utilization and homeostasis. In particular, miRNAs control the differentiation, survival and activation of CD4+ T conventional (Tconv) cells, key players of the adaptive immunity and miRNA-mediated gene expression regulation contributes to the physiological response to infections and the pathological loss of immune homeostasis in autoimmunity. Upon T cell receptor (TCR) stimulation, the described global miRNA quantitative decrease occurring in T cells is believed to promote the acquisition of effector functions by relaxing the post-transcriptional repression of genes associated to proliferation and cell activity. While miRNAs were initially thought to get down-regulated uniquely by intracellular degradation, miRNA secretion via extracellular vesicles (EVs) represents an additional mechanism of rapid down-regulation. By focusing on molecular interactions by means of graph theory, we have found that miRNAs released by TCR stimulated Tconv cells are significantly enriched for targeting transcripts up-regulated upon stimulation, including those encoding for crucial proteins associated to Tconv cell activation and function. Based on this computational approach, we present our perspective based on the following hypothesis: a stimulated Tconv cell will release miRNAs targeting genes associated to the effector function in the extracellular space in association with EVs, which will thus possess a suppressive potential toward other Tconv cells in the paracrine environment. We also propose possible future directions of investigation aimed at taking advantage of these phenomena to control Tconv cell effector function in health and autoimmunity.
Project description:Foxp3+ regulatory T (Treg) cells prevent inflammatory disease but the mechanistic basis of suppression is not understood completely . Gene silencing by RNA interference can act in a cell-autonomous and non-cell-autonomous manner, providing mechanisms of inter-cellular regulation. Here, we demonstrate that non-cell-autonomous gene silencing, mediated by miRNA-containing exosomes, is a mechanism employed by Treg cells to suppress T cell-mediated disease. Treg cells transferred microRNAs (miRNA) to various immune cells, including T helper 1 (Th1) cells, suppressing Th1 cell proliferation and cytokine secretion. Use of Dicer-deficient or Rab27a and Rab27b double-deficient Treg cells to disrupt miRNA-biogenesis or the exosomal pathway, respectively, established a requirement for miRNAs and exosomes for Treg cell-mediated suppression. Transcriptional analysis and miRNA inhibitor studies showed that exosome-mediated transfer of Let-7d from Treg cell to Th1 cells contributed to suppression and prevention of systemic disease. These studies reveal a mechanism of Treg cell-mediated suppression mediated by miRNA-containing exosomes. Regulatory T cells (CD4+CD25hiFoxp3rfp+, Treg) were isolated from naive mice. RNA as extracted form some Treg cells, while others were cultured in complete IMDM media for 3 days, stimulated with anti-CD3 anti-CD3 (1ug/ml) and anti-CD28 (10ug/ml). Exosomes were recovered from Treg cell supernatant, as described, and RNA was extracted form the purified exosomes. To identify which miRNAs were transferred to Dicer-deficient (KO) cells from Treg cells, we cultured Dicer KO cells alone, or co-cultured Dicer KO cells with Treg cells. RNA was extracted form Dicer KO cells cultured alone or from Dicer KO cells cultured in the presence of Treg cells. 3 x biological replicates were used. Each biological replicate was derived from a pool of 3-5 samples.