Potential Role of microRNAs in Response to Aeromonas Infection in Fish.

The genus Aeromonas is a widespread pathogen that includes more than 30 Gram-negative species, many of which are opportunistic bacteria. Aeromonas species are naturally distributed in various aquatic sources. Infectious processes in marine animals such as fish usually develop under stressful conditions, and when their immune systems are weakened. MicroRNAs (miRNAs/miRs) are short, non-coding RNAs that post-transcriptionally regulate gene expression. Their diverse biological functions, such as influencing cell development, proliferation, differentiation, tumorigenesis, metabolism, and apoptosis have been studied in various animals. Fish is the most important source of aquatic nutrients throughout the world, and its market is constantly growing. Overpopulation in aquaculture brings infectious diseases that threaten the development of aquaculture around the world. There is extensive evidence that microRNAs are involved in modulating infectious processes and regulating the inflammatory response to major bacterial fish infections, including Aeromonas. Here, we review the current literature on the fish microRNA repertoire and outline the physiological roles assigned to microRNAs to provide a foundation for future research during Aeromonas infection. Understanding the interaction between microRNAs and Aeromonas may provide clues to a remarkable strategy for preventing Aeromonas infections in fish.

All-trans retinoic acid preconditioning enhances proliferation, angiogenesis and migration of mesenchymal stem cell in vitro and enhances wound repair in vivo.

OBJECTIVES: Stem cell therapy is considered to be a suitable alternative in treatment of a number of diseases. However, there are challenges in their clinical application in cell therapy, such as to reduce survival and loss of transplanted stem cells. It seems that chemical and pharmacological preconditioning enhances their therapeutic efficacy. In this study, we investigated effects of all-trans retinoic acid (ATRA) on survival, angiogenesis and migration of mesenchymal stem cells (MSCs) in vitro and in a wound-healing model. MATERIALS AND METHODS: MSCs were treated with a variety of concentrations of ATRA, and mRNA expression of cyclo-oxygenase-2 (COX-2), hypoxia-inducible factor-1 (HIF-1), C-X-C chemokine receptor type 4 (CXCR4), C-C chemokine receptor type 2 (CCR2), vascular endothelial growth factor (VEGF), angiopoietin-2 (Ang-2) and Ang-4 were examined by qRT-PCR. Prostaglandin E2 (PGE2) levels were measured using an ELISA kit and MSC angiogenic potential was evaluated using three-dimensional tube formation assay. Finally, benefit of ATRA-treated MSCs in wound healing was determined with a rat excisional wound model. RESULTS: In ATRA-treated MSCs, expressions of COX-2, HIF-1, CXCR4, CCR2, VEGF, Ang-2 and Ang-4 increased compared to control groups. Overexpression of the related genes was reversed by celecoxib, a selective COX-2 inhibitor. Tube formation and in vivo wound healing of ATRA-treated MSCs were also significantly enhanced compared to untreated MSCs. CONCLUSION: Pre-conditioning of MSCs with ATRA increased efficacy of cell therapy by activation of survival signalling pathways, trophic factors and release of pro-angiogenic molecules.