For the early diagnosis of gastric cancer, microRNA-148a (miRNA-148a) as a promising biomarker is measured by a simple colorimetric biosensor due to its unique surface plasmon resonance (SPR) absorption of gold nanoparticles (AuNPs). In the assay system, the sensing probes are facilitated by the conjugation of AuNPs with RNA probes (RNAP) via Au–S bonds, which align in a tail-to-tail fashion onto the target RNA. When miRNA-148a is introduced, a sandwich hybridization reaction is triggered between the AuNP–RNAP conjugates and targets, resulting in changes in the SPR absorption band, microscopic distribution and macroscopic color of the AuNP solution. Following this principle, this colorimetric method is able to quantitatively detect miRNA-148a at nanomolar level with a limit of ∼1.9 nM, and exhibits high sensitivity and selectivity by a low-cost UV–vis spectrometer or even the naked eye. Moreover, the AuNP network materials with a characteristic sharp 'melting transition' provide significant guidance for the reusability of DNA or RNA biosensors.
Lin Ling,Li Wei,Gao Xinjing,Li Qian,Zhou Xin,Liu Weiyu,Zhong Xuelian,Yang Yunqing,Zhang Xibao,Luo Quan
Psoriasis represents a chronic inflammatory skin disease occurring globally. We investigated the role of plasma exosomal microRNA (miR)- 148a- 3p and its target gene Bim in psoriasis. Plasma exosomes (Exos) and CD4 + T cells were extracted from psoriatic patients. miR- 148a- 3p expression in Exos and CD4 + T cells of psoriatic patients, the proportions of CD4 + T cell subsets, and the contents of anti-inflammatory/pro-inflammatory factors were determined by RT-qPCR, flow cytometry and ELISA. The correlation between plasma exosomal miR- 148a- 3p and CD4 + T cell subsets in psoriatic patients was analyzed by Pearson’s analysis. The psoriatic mouse was treated with Exos/antagomir miR- 148a- 3p. Histopathological changes in the skin were observed. The CD4 + T cell subset levels, serum cytokine contents and miR- 148a- 3p expression in the blood were measured. The miR- 148a- 3p-Bim targeted binding relationship was predicted and verified by Starbase database and dual-luciferase assay. The Bim expression in psoriatic mice was determined. Psoriatic patients had highly-expressed miR- 148a- 3p in both Exos and CD4 + T cells, and abnormal CD4 + T cell subsets and cytokine levels. Plasma exosomal miR- 148a- 3p was correlated with the CD4 + T cell subsets in psoriatic patients. Exos caused down-regulated miR- 148a- 3p level in skin tissues of mouse, regulated CD4 + T cell function and aggravated the symptoms in psoriatic mice. miR- 148a- 3p repression partially reversed the role of Exos in CD4 + T cell function and psoriasis-like symptoms. Exos-carried miR- 148a- 3p targeted Bim in CD4 + T cells of psoriatic mice. Plasma exosomal miR- 148a- 3p targeted Bim to affect the dysfunction of CD4 + T cells in psoriatic mice, thereby aggravating the psoriasis-like symptoms.
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