Non-Coding RNA

Background/Objectives: In severe peripheral artery disease (PAD) with limb ischemia, hypercholesterolemia (HC) is associated with impaired neovascularization. Extracellular vesicles (EVs) are present within ischemic muscles, and they contain microRNAs (miRs) involved in several biological functions, including angiogenesis and neovascularization. Methods: We used a mouse model of PAD and compared the response to hindlimb ischemia in hypercholesterolemic ApoE^−/− vs. normocholesterolemic mice. Next-generation sequencing (NGS) was used to perform full miR expression profiling in ischemic skeletal muscles and in EVs of varying sizes—large EVs (lEVs) and small EVs (sEVs)—within these muscles. Results: We identified several miRs with potential pro-angiogenic effects (angiomiRs) that are reduced by HC in lEVs (Let-7b-5p, miR-151-3p, Let-7c-5p) or sEVs (miR-21a-5p, miR-196b-5p, miR-340-5p). As proof of principle, we showed that the overexpression of Let-7b-5p in lEVs, or miR-21a-5p in sEVs, can significantly increase the angiogenic capacity of these EVs in vitro. HC also impaired the enrichment of specific angiomiRs in lEVs (miR-100-5p), sEVs (miR-142a-3p), or in both lEVs and sEVs (miR-146b-5p). In silico approaches, including the prediction of miR targets, pathway unions, and gene unions, identified the resulting predictive effects of HC-modulated miRs in EVs on processes with key roles in the modulation of angiogenesis and neovascularization, such as the regulation of the actin cytoskeleton and focal adhesion and the HIF-1, MAPK, AMPK, and PI3K-Akt signaling pathways. Conclusions: Our results constitute an important first step towards the identification of specific miRs that could be targeted to improve EV angiogenic function in hypercholesterolemic conditions and reduce tissue ischemia in patients with severe PAD.

Diffuse large B-cell lymphoma (DLBCL) is the most common and clinically aggressive subtype of non-Hodgkin lymphoma (NHL). While novel therapies such as rituximab and polatuzumab vedotin have led to improved outcomes, approximately 35% of patients eventually develop relapsed or refractory disease. MicroRNAs (miRNAs), a class of endogenous single-stranded RNAs approximately 22 nucleotides in length, play a pivotal role in the regulation of gene expression at the post-transcriptional level through interactions with complementary target RNAs and contribute significantly to the development, progression, and treatment response of DLBCL. Oncogenic miRNAs, such as miR-155, miR-21, and the miR-17–92 cluster, promote proliferation, survival, immune evasion, and therapy resistance by modulating pathways including PI3K/AKT, NF-κB, and MYC. Conversely, tumor-suppressive miRNAs such as miR-34a, miR-144, miR-181a, and miR-124-3p inhibit oncogene activity and enhance apoptosis, with their loss often associated with adverse outcomes. Among these, miR-155 and miR-21 are particularly well studied, playing central roles in both tumor progression and remodeling of the tumor microenvironment. This review summarizes current evidence on the biological and clinical relevance of miRNAs in DLBCL, emphasizing their diagnostic and prognostic potential.

Background/Objectives: Bone marrow mesenchymal stromal cells (MSCs) are therapeutic cells that adopt an immunomodulatory phenotype when exposed to pro-inflammatory cytokines. Recent research efforts uncovered that many therapeutic benefits of MSCs can be attributed to the secretion of extracellular vesicles (EVs) such as exosomes, small membrane vesicles of endocytic origin present in the cellular secretome. EVs’ formation and release are impacted by the autophagy pathway, which recycles proteins and organelles via lysosomal degradation. Methods: To evaluate how modulation of autophagy affects properties of MSC EVs enriched in exosomes under pro-inflammatory conditions, we treated the cells with either tamoxifen (TX) or chloroquine (CQ), two drugs known to stimulate or inhibit autophagy, respectively, together with IFNγ. MSC EVs enriched in exosomes were then purified from serum-free media, and their immunoregulatory properties were evaluated ex vivo using activated CD4 T cells; small RNA sequencing was also conducted to determine EVs’ microRNA content. Results: Our data indicate that MSCs treated with CQ + IFNγ yield EVs that possess somewhat higher capacity to decrease T cell proliferation compared to other EVs. Small RNA sequencing revealed that, although similar microRNAs were found in EVs isolated from all treated cells, the treatments exerted more effect on the levels of multiple microRNAs that are known to regulate either cancer or inflammation-related biological pathways in target cells. Conclusions: Overall, we conclude that the co-treatment of MSCs with TX or CQ in the presence of pro-inflammatory cytokine IFNγ has the potential to modulate microRNA content of EVs, potentially affecting biological properties of such EVs and their effect on target cells.