º£½ÇÆƽâ°æ

Circular RNAs (circRNAs) are a family of non-coding RNAs that originate from a non-canonical splicing event (backsplicing) that forms covalently closed continuous loops. An analysis of the human immunodeficiency type 1 virus (HIV-1) complex splicing pattern indicated that the virus had the potential to generate at least 15 distinct circRNAs. The predicted HIV circRNAs were amplified utilizing divergent PCR primers and confirmed by RNase R digestion and sequencing. A predictive circRNA-miRNA interaction modeling approach and a series of validation assays determined that two cellular miRNAs, miR-6727-3p and miR-4722-3p, functionally interact with a sequence present in 8 of the HIV circRNAs. Expression of miR-6727-3p and miR-4722-3p restricted HIV-1 replication while a circRNA containing the sequence recognized by miR-6727-3p and miR-4722-3p increased the production of infective virions. Additionally, miR-6727-3p and miR-4722-3p expression was upregulated following HIV-1 infection of primary CD4+ T cells. Overall, the data presented shows that HIV-1 generates circRNAs which promote viral replication by sequestering and inhibiting the functions of miR-6727-3p and miR-4722-3p.

BackgroundPrevious research showed that the intracellular complement system, with CD46 as its central molecule, regulates the Th1 response associated with IFN-¦Ã production and transition to a type 1 regulatory response (Tr1) characterized by IL-10 production. This transition can be influenced by a vitamin D (calcitriol), favouring a shift towards Tr1 cells and increased IL-10 production, as described in some autoimmune diseases.ObjectiveIt is unknown whether calcitriol modulates CD46-induced Th1 response towards regulatory type 1 T cells (Tr1) in allergic eosinophilic asthma and its value in relation to reducing inflammatory response.MethodsCD4+ T cells from 58 patients with allergic eosinophilic asthma (AEA) and 49 healthy donors (HDs) were stimulated with ¦ÁCD3/¦ÁCD46/IL-2 or ¦ÁCD3/¦ÁCD46/IL-2/Calcitriol in vitro for 60 h and analyzed by flow cytometry. IFN-¦Ã and IL-10 levels in cell culture supernatants were measured using ELISA.ResultsCD4+ T cells from patients with AEA demonstrated elevated CD46 expression in both the non-activated state and under stimulation conditions with ¦ÁCD3/¦ÁCD46/IL-2 or ¦ÁCD3/¦ÁCD46/IL-2/Calcitriol. Moreover, CD46 expression in AEA patients fluctuated with the pollen season, showing a significant increase during period of low pollen exposure. Calcitriol further induced CD4+Tr1 cells from in vitro generated CD4+Th1 cells in both HDs and AEA patients. However, in both cohorts were individuals (HDs: 35/49, AEA: 40/58) who responded to calcitriol with a more pronounced regulatory response. The calcitriol-induced regulatory effect manifested by a stronger surface decrease of CD46 on activated CD4+ T cells (by 40% in HDs and by 26% in AEA), accompanied by a significant inhibition of IFN-¦Ã and increased IL-10 production (by 31% in HDs and by 85% in AEA). These individuals were termed as the CD46D group. Contrary to this, calcitriol induced an increase in CD46 expression at the CD4+ T cell surface in a minor group of HDs (14/49), and AEA patients (18/58), who were termed as the CD46I group. In CD46I group, CD4+ T cells produced less IFN-¦Ã in comparison with CD46D group (by 33% in HDs and by 43% in AEA) and were unable to upregulate IL-10 production following stimulation with ¦ÁCD3/¦ÁCD46/IL-2/Calcitriol.ConclusionOur results suggest the potential existence of a key for stratifying individuals suitable for calcitriol treatment in the context of low serum vitamin D levels. After validation in clinical studies, this key could be used as an adjunctive therapy not only for patients with allergic eosinophilic asthma, but also for other diseases.