Establishment of lipofection for studying miRNA function in human adipocytes

T14diLys/DOPE Liposomes: An Innovative Option for siRNA-Based Gene Knockdown?

BACKGROUND/OBJECTIVES

Bringing small interfering RNA (siRNA) into the cell cytosol to achieve specific gene silencing is an attractive but also very challenging option for improved therapies. The first step for successful siRNA delivery is the complexation with a permanent cationic or ionizable compound. This protects the negatively charged siRNA and enables transfection through the cell membrane. The current study explores the performance of the innovative, ionizable lipid 2-Tetradecylhexadecanoic acid-(2-bis{[2-(2,6-diamino-1-oxohexyl)amino]ethyl}aminoethyl)-amide (T14diLys), in combination with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), for siRNA delivery and the impact of the production method (sonication vs. extrusion) on the particle properties.

METHODS

Liposomes were produced either with sonication or extrusion and characterized. The extruded liposomes were combined with siRNA at different N/P ratios and investigated in terms of size zeta potential, encapsulation efficiency, lipoplex stability against RNase A, and knockdown efficiency using enhanced green fluorescent protein (eGFP)-marked colon adenocarcinoma cells.

RESULTS

The liposomes prepared by extrusion were smaller and had a narrower size distribution than the sonicated ones. The combination of siRNA and liposomes at a nitrogen-to-phosphate (N/P) ratio of 5 had optimal particle properties, high encapsulation efficiency, and lipoplex stability. Gene knockdown tests confirmed this assumption.

CONCLUSIONS

Liposomes produced with extrusion were more reproducible and provided enhanced particle properties. The physicochemical characterization and in vitro experiments showed that an N/P ratio of 5 was the most promising ratio for siRNA delivery.

An optimized method for gene knockdown in differentiating human and mouse adipocyte cultures

Adipocyte cultures are a mainstay of metabolic disease research, yet loss-of-function studies in differentiating adipocytes is complicated by the refractoriness of lipid-containing adipocytes to standard siRNA transfections. Alternative methods, such as electroporation or adenovirus/lentivirus-based delivery systems are complex, expensive and often accompanied with unacceptable levels of cell death. To address this problem, we have tested two commercially available siRNA delivery systems in this study using a multi-parameter optimization approach. Our results identified a uniform siRNA transfection protocol that can be applied to human and mouse adipocyte cultures throughout the time course of differentiation, beginning with pre-differentiated cells and continuing up to lipid-accumulated differentiated adipocytes. Our findings allow for efficient transfection of human and mouse adipocyte cultures using standard and readily available methodologies, and should help significantly expand the scope of gene manipulation studies in these cell types.

MicroRNA-27a-3p enhances the inflammatory phenotype of Juvenile Idiopathic Arthritis fibroblast-like synoviocytes

BACKGROUND

Juvenile Idiopathic Arthritis (JIA) is the most prevalent chronic pediatric rheumatic disorder. In joints of JIA patients, aggressive phenotypic changes in fibroblast-like synoviocytes (FLS) of the synovial lining play a key role in inflammation. MicroRNAs are dysregulated in rheumatoid arthritis and JIA, including miR-27a-3p. However, it is not understood if miR-27a-3p, enriched in JIA synovial fluid (SF) and leukocytes, alters FLS function.

METHODS

Primary JIA FLS cells were transfected with a miR-27a-3p mimic or a negative control microRNA (miR-NC) and stimulated with pooled JIA SF or inflammatory cytokines. Viability and apoptosis were analyzed by flow cytometry. Proliferation was evaluated using a ³H-thymidine incorporation assay. Cytokine production was assessed by qPCR and ELISA. Expression of TGF-β pathway genes was determined using a qPCR array.

RESULTS

MiR-27a-3p was constitutively expressed in FLS. Overexpression of miR-27a-3p caused increased interleukin-8 secretion in resting FLS, and interleukin-6 was elevated in SF-activated FLS compared to miR-NC. Furthermore, stimulation with pro-inflammatory cytokines augmented FLS proliferation in miR-27a-3p-transfected FLS relative to miR-NC. Expression of multiple TGF-β pathway genes was modulated by overexpression of miR-27a-3p.

CONCLUSIONS

MiR-27a-3p significantly contributes to FLS proliferation and cytokine production, making it a potential candidate for epigenetic therapy that targets FLS in arthritis.

Strategies for transfection of bovine mesenchymal stem cells with pBC1-anti-CD3 vector

Cells from different origins behave differently regarding the incorporation of exogenous DNA and formation of transgenic cells. Milk production of recombinant antibody may benefit from efficient transfection protocols to produce transgenic animals. In this context, the objective of this study was to verify the transfection potential of bovine mesenchymal stem cells from Wharton's jelly (MSC-WJ) and adipose tissue (MSC-AT), comparing co-transfection protocols with vectors pBC1-anti-CD3 and pEF-NEO-GFP, using transfection reagents Lipofectamine LTX with Plus Reagent or Xfect. Skin fibroblasts (FIB) were used as the control group. Forty-eight hours after transfection, neomycin was added and cells cultured for 2 weeks. Treated cells were submitted to fluorescence microscopy, flow cytometry, and PCR evaluations. Wharton's jelly cells were sensitive to treatments and started necrosis. In the flow cytometry assay, the median fluorescence was higher in adipocytes than fibroblasts, for both the Xfect (20.057 ± 1.620,7 and 10.601 ± 702,86, respectively, p < 0.05) and LTX (19.590 ± 113,84 and 10.518 ± 442,65, respectively, p < 0.05). These results, associated with evaluation of epifluorescence, demonstrated that adipocytes presented a better response to transfection than other cells, independent of the kit used. Performing PCR on co-transfected cells demonstrated the presence of anti-CD3, making this approach feasible for future experiments.

The Promise and Challenges of Developing miRNA-Based Therapeutics for Parkinson's Disease

MicroRNAs (miRNAs) are small double-stranded RNAs that exert a fine-tuning sequence-specific regulation of cell transcriptome. While one unique miRNA regulates hundreds of mRNAs, each mRNA molecule is commonly regulated by various miRNAs that bind to complementary sequences at 3’-untranslated regions for triggering the mechanism of RNA interference. Unfortunately, dysregulated miRNAs play critical roles in many disorders, including Parkinson’s disease (PD), the second most prevalent neurodegenerative disease in the world. Treatment of this slowly, progressive, and yet incurable pathology challenges neurologists. In addition to L-DOPA that restores dopaminergic transmission and ameliorate motor signs (i.e., bradykinesia, rigidity, tremors), patients commonly receive medication for mood disorders and autonomic dysfunctions. However, the effectiveness of L-DOPA declines over time, and the L-DOPA-induced dyskinesias commonly appear and become highly disabling. The discovery of more effective therapies capable of slowing disease progression –a neuroprotective agent–remains a critical need in PD. The present review focus on miRNAs as promising drug targets for PD, examining their role in underlying mechanisms of the disease, the strategies for controlling aberrant expressions, and, finally, the current technologies for translating these small molecules from bench to clinics.

MicroRNA-mediated regulation of BM-MSCs differentiation into sweat gland-like cells: targeting NF-κB

Sweat gland regeneration is important for patients with an extensive deep burn injury. In previous study, we reported that bone marrow-mesenchymal stem cells (BM-MSCs) could differentiate into sweat gland-like cells (SGLCs), but the underlying molecular mechanism remains unclear. Recently, microRNAs (miRNAs or miRs) are reported to manipulate many biological processes. However, whether the process of MSCs differentiation into sweat gland cells (SGCs) is regulated by miRNAs has not been reported. In this study, BM-MSCs were induced into SGLCs by co-culturing with SGCs. Differential expressions of miRNAs between BM-MSC and SGLCs were determined through miRNAs microarray and 68 miRNAs were found significantly changed in miRNA profile including hsa-miR-138-5p. Bioinformatics analysis showed that hsa-miR-138-5p targeted a group of nuclear factor-κB (NF-κB) related genes which play an important role in skin appendage development. As expected, hsa-miR-138-5p inhibitor transfected into BM-MSCs partly mimicked the effects of co-culture and increased the number of SGLCs by increasing the expression of NF-κB related genes. These results suggest that hsa-miR-138-5p and NF-κB are involved in the regulation of BM-MSCs differentiation into SGLCs. This study may also offer a new approach to yield SGCs for burn patients.

Differential expression of miRNAs related to angiogenesis and adipogenesis in subcutaneous fat of obese and nonobese women

To disclose the mechanisms surrounding obesity, we selected microRNAs (miRNAs) that target genes involved in adipogenesis, angiogenesis, and inflammation and compared their expression levels in the subcutaneous adipose tissue of 40 obese and nonobese women. Mature miRNAs were extracted from subcutaneous adipose tissue samples that were collected during surgery and quantified by real-time polymerase chain reaction. miR-16 was overexpressed in the nonobese group (n-expression ratio = - 151.1; P < 0.001). Furthermore, the expression levels of two other miRNAs were significantly correlated with waist circumference in nonobese women (miR-27b, r = 0.453; P = 0.027 and miR-424-5p, r = 0.502, P = 0.014). Central and total subcutaneous adipose tissue thicknesses were correlated with miR-424-5p levels (r = 0.506, P = 0.034 and r = 0.475, P = 0.046, respectively) in the nonobese group. In the obese group, miR-424-5p expression was correlated with body mass index (r = 0.582, P = 0.018). miR-16 and miR-424 have shown correlations with body-fat-mass-related parameters. Because these miRNAs have vascular endothelial growth factor (VEGF) and its receptors as target genes, they may be involved in the alterations of angiogenesis observed in obesity. In addition, higher levels of miR-27 and miR-424 were correlated with higher fat depot measurements in nonobese women. These results highlight the importance of miRNA expression in subcutaneous adipose tissue and encourage further investigation of miRNAs as prognostic markers.

Delivery of siRNA silencing P-gp in peptide-functionalized nanoparticles causes efflux modulation at the blood–brain barrier

Aim: Explore the use of transferrin-receptor peptide-functionalized nanoparticles (NPs) targeting blood–brain barrier (BBB) as siRNA carriers to silence P-glycoprotein (P-gp). Materials & methods: Permeability experiments were assessed through a developed BBB cell-based model; P-gp mRNA expression was evaluated in vitro; rhodamine 123 permeability was assessed after cell monolayer treatment with siRNA NPs. Results: Beyond their ability to improve siRNA permeability through the BBB by twofold, 96-h post-transfection, functionalized polymeric NPs successfully reduced P-gp mRNA expression up to 52%, compared with nonfunctionalized systems. Subsequently, the permeability of rhodamine 123 through the human BBB model increased up to 27%. Conclusion: Developed BBB-targeted NPs induced P-gp downregulation and consequent increase on P-gp substrate permeability, revealing their ability to modulate drug efflux at the BBB.

Delivery of RNA-based molecules to human hematopoietic stem and progenitor cells for modulation of gene expression

Gene modulation of human hematopoietic stem and progenitor cells (HSPCs) harbors great potential for therapeutic application of these cells and presents a versatile tool in basic research to enhance our understanding of HSPC biology. However, stable genetic modification might be adverse, particularly in clinical settings. Here, we review a broad range of approaches to transient, nonviral modulation of protein expression with a focus on RNA-based methods. We compare different delivery methods and describe the usefulness of RNA molecules for overexpression as well as downregulation of proteins in HSPCs.

Lipid Nanovectors to Deliver RNA Oligonucleotides in Cancer

The growing knowledge on the mechanisms of gene silencing and gene regulation by non-coding RNAs (ncRNA), mainly small interfering RNA (siRNA) and microRNA (miRNA), is providing a significant boost to the development of new therapeutic strategies for the treatment of cancer. However, the design of RNA-based therapeutics is hampered by biopharmaceutical issues, thus requiring the use of suitable delivery strategies. In this regards, lipid nanovectors have been successfully investigated to deliver RNA in different forms of cancer. Compared to other biomaterials, lipids offer advantages such as biocompatibility, biodegradability, easy production, low cost, limited toxicity and immunogenicity. The possibility to formulate these materials in the form of nanovectors allows overcoming biopharmaceutical issues associated to the therapeutic use of RNA, with the possibility to target tumors. This review takes stock of the main lipid nanovectors proposed to deliver ncRNA. For each considered delivery strategy, the rational design and the most meaningful in vitro and in vivo results are reported and discussed.