Lipofectamine RNAiMAX Research Articles

Microneedle-Mediated Delivery of siRNA via Liposomal-Based Transfection for Inner Ear Gene Therapy.

Microneedle-mediated intracochlear injection of siRNA-Lipofectamine through the round window membrane (RWM) can be used to transfect cells within the cochlea. Our laboratory has developed 100-μm diameter hollow microneedles for intracochlear injection through the guinea pig RWM. In this study, we test the feasibility of microneedle-mediated injection of siRNA and Lipofectamine, a commonly used reagent with known cellular toxicity, through the RWM for cochlear transfection. Fluorescently labeled scramble siRNA was diluted into Lipofectamine RNAiMax and OptiMEM. One microliter of 5 μM siRNA was injected through the RWM of Hartley guinea pigs at a rate of 1 μl/min (n = 22). In a control group, 1.0 μl of Lipofectamine, with no siRNA, was diluted into OptiMEM and injected in a similar fashion (n = 5). Hearing tests were performed before and either at 24 hours, 48 hours, or 5 days after injection. Afterward, animals were euthanized, and cochleae were harvested for imaging. Control cochleae were processed in parallel to untreated guinea pigs. Fluorescence, indicating successful transfection, was observed within the basal and middle turns of the cochlea with limited distribution in the apex at 24 and 48 hours. Signal was most intense in the organ of Corti, spiral ligament, and spiral ganglion. Little to no fluorescence was observed at 5 days post-injection. No significant changes in auditory brainstem response (ABR) were noted post-perforation at 5 days, suggesting that siRNA-Lipofectamine at low doses does not cause cochlear toxicity. Small volumes of siRNA and Lipofectamine can be effectively delivered to cochlear structures using microneedles, paving the way for atraumatic cochlear gene therapy.

CREG1 deficiency impaired myoblast differentiation and skeletal muscle regeneration.

CREG1 (cellular repressor of E1A-stimulated genes 1) is a protein involved in cellular differentiation and homeostasis regulation. However, its role in skeletal muscle satellite cells differentiation and muscle regeneration is poorly understood. This study aimed to investigate the role of CREG1 in myogenesis and muscle regeneration. RNA sequencing data (GSE8479) was analysed from the Gene Expression Omnibus database (GEO, https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi). We generated Creg1 knockdown and skeletal muscle satellite cells specific Creg1 overexpression mice mediated by adeno-associated virus serotype 9 (AAV9), skeletal muscle mature myofibre Creg1 knockout mice (myoblast/Creg1MKO), and control mice Creg1flox/flox (Creg1fl/fl) as in vivo models. The mice were injected into tibialis anterior (TA) muscle with 100μL of 10μM cardiotoxin to establish a muscle regeneration model. Creg1fl/fl and Creg1MKO mice were treated with AAV-sh-C-Cbl (2×1010 genomic copies/mouse) to silence C-Cbl in the TA muscle. 293T and C2C12 cells were transfected with plasmids using lipofectamine RNAi MAX in vitro. Mass spectrometry analyses and RNA sequencing transcriptomic assay were performed. We analysed the transcriptional profiles of the skeletal muscle biopsies from healthy older (N=25) and younger (N=26) adult men and women in GSE8479 database, and the results showed that Creg1 was associated with human sarcopenia. We found that Creg1 knockdown mice regenerated less newly formed fibres in response to cardiotoxin injection (~30% reduction, P<0.01); however, muscle satellite cells specific Creg1 overexpression mice regenerated more newly formed fibres (~20% increase, P<0.05). AMPKa1 is known as a key mediator in the muscle regeneration process. Our results revealed that CREG1 deficiency inhibited AMPKa1 signalling through C-CBL E3-ubiquitin ligase-mediated AMPKa1 degradation (P<0.01). C-CBL-mediated AMPKa1 ubiquitination was attributed to the K48-linked polyubiquitination of AMPKa1 at K396 and that the modification played an important role in the regulation of AMPKa1 protein stability. We also found that Creg1MKO mice regenerated less newly formed fibres compared with Creg1fl/fl mice (~30% reduction, P<0.01). RNA-seq analysis showed that CREG1 deletion in impaired muscles led to the upregulation of inflammation and DKK3 expression. The TA muscles of Creg1MKO mice were injected with AAV-vector or AAV-shC-Cbl, silencing C-CBL (P<0.01) in the skeletal muscles of Creg1MKO mice significantly improved muscle regeneration induced by CTX injury (P<0.01). Our findings suggest that CREG1 may be a potential therapeutic target for skeletal muscle regeneration.

Delivery of RNA to the Blood-Brain Barrier Endothelium Using Cationic Bicelles.

Blood-brain barrier (BBB) dysfunction is prevalent in Alzheimer's disease and other neurological disorders. Restoring normal BBB function through RNA therapy is a potential avenue for addressing cerebrovascular changes in these disorders that may lead to cognitive decline. Although lipid nanoparticles have been traditionally used as drug carriers for RNA, bicelles have been emerging as a better alternative because of their higher cellular uptake and superior transfection capabilities. Cationic bicelles composed of DPPC/DC7PC/DOTAP at molar ratios of 63.8/25.0/11.2 were evaluated for the delivery of RNA in polarized hCMEC/D3 monolayers, a widely used BBB cell culture model. RNA-bicelle complexes were formed at five N/P ratios (1:1 to 5:1) by a thin-film hydration method. The RNA-bicelle complexes at N/P ratios of 3:1 and 4:1 exhibited optimal particle characteristics for cellular delivery. The cellular uptake of cationic bicelles laced with 1 mol% DiI-C18 was confirmed by flow cytometry and confocal microscopy. The ability of cationic bicelles (N/P ratio 4:1) to transfect polarized hCMEC/D3 with FITC-labeled control siRNA was tested vis-a-vis commercially available Lipofectamine RNAiMAX. These studies demonstrated the higher transfection efficiency and greater potential of cationic bicelles for RNA delivery to the BBB endothelium.

MicroRNA-221-3p promotes cell proliferation, migration, and invasion in gastric cancer by modulating PIK3R1

Background: Gastric cancer (GC), which is the fourth most prevalent cancer in the world is significantly threatened the health of people, particularly those in developing nations. Nearly all significant pathological and physiological mechanisms, including apoptosis, proliferation, cell cycle, differentiation, as well as DNA damage, are regulated by miRNAs. This study looked at the miR-221-3p expression and to identified it's target genes in GC tissue specimens and cell lines, to comprehend the miR-221-3p influence in the development of GC. Methods: GC tissues and matched marginal tissues were taken from 50 patients undergo gastric surgery. MiR-221-3p mimics, inhibitors and negative controls (NC) were transfected into MKN-45 cells, using Lipofectamine RNAiMAX reagent. The proliferation was assessed by the MTT assay. Cell migration and invasion was assessed by Transwell assay. By combining Western blotting and qRT-PCR, the impact of miR-221-3p in the PIK3R1 expression in gastric cancer cells was examined. Results: Overexpression of miR-221-3p significantly enhanced the migration, invasion and proliferation of gastric cancer cells, conversely, transfection of miR-221-3p inhibitor led to opposite effect caused by overexpression of this miRNA on phenotypic characteristics of gastric cancer cell line. Additional investigation revealed that PIK3R1 was downregulated significantly by overexpression of miR-221-3p. Whereas, when the MKN-45 cells transfected with miR-221-3p inhibitor, PIK3R1 was noticeably overexpressed. Conclusions: Our current data indicate that miR-221-3p possibly work as a tumor promoter in the development of gastric cancer by negatively regulating PIK3R1 expression, hence miR-221-3p/ PIK3R1 highlighted as promising therapeutic targets or prognostic and diagnostic biomarkers for GC patients.

Abstract 6285: MicroRNA-217 affects tumor microenvironment and enhances the chemosensitivity of pancreatic cancer

Abstract Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies and an inherently chemoresistant tumor. Dense fibrotic stroma is a major obstacle for drug delivery to the tumor cells in PDAC. Pancreatic stellate cells (PSCs) are the major stromal cells responsible for fibrotic microenvironment. MicroRNA-217 (miR-217) is known mainly as a tumor suppressor. However, the detailed roles of miR-217 on pathophysiology of PDAC remain unclarified. Methods: Expressions levels of miR-217 were measured in surgically resected human PDAC samples. Using Lipofectamine RNAiMAX, miR-217 or negative control miR (NC) were transfected in human pancreatic cancer cells, Panc-1, MIApaca-2, BxPC-3 and murine PAN02 cells, and chemosensitivities to gemcitabine and paclitaxel were investigated by MTS assay. Human hPSC-1 (obtained from Riken cell bank, Japan) was cultured in 20%FBS+DMEM and the changes of phenotypes and expression levels of miR-217 after the stimulation with TGF-β1 was measured by fluorescein microscope and digital PCR, respectively. Results: The expression level of miR-217 was markedly downregulated in PDAC tissues than in noncancerous pancreatic tissues (P&amp;lt;0.001, n=9). Overexpression of miR-217 significantly inhibited the proliferation of Panc-1, MIApaca-2 and BxPC-3 (P&amp;lt;0.001) and migration of Panc-1, MIApaca-2 and PAN02 (P&amp;lt;0.05). Lipofection of miR-217 further reduced the number of PAN02 exposed to 1-5nM gemcitabine (P&amp;lt;0.0001) and 0.01-0.1uM paclitaxel (P=0.0085) which resulted in the reduced the IC-50 as compared with NC. Human PSC-1 stimulated with TGF-β1 (10ng/ml) significantly reduced miR-217 expression compared to nascent cells. The stimulation with TGF-β1 upregulated the expression of cancer associated fibroblast (CAF) markers, α-smooth muscle actin (SMA) and vimentin. However, the expression levels of these markers were significantly reduced by the kipofection of miR-217. Conclusion: MiR-217 affects both cancer and stromal cells in PDAC which may regulate chemosensitivity in PDAC. Restoring miR-217 levels in tumor cells and/or PSCs could be a future therapeutic strategy. Citation Format: Yuki Kaneko, HIdeyuki Ohzawa, Yuki Kimura, Kohei Tamura, Yurie Futoh, Kazuya Takahashi, Akira Saito, Mineyuki Tojo, Hideyo Miyato, Naohiro Sata, Joji Kitayama. MicroRNA-217 affects tumor microenvironment and enhances the chemosensitivity of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6285.

Increased Connexin 43 expression in AMPK deficient cardiomyocytes in response to Doxorubicin treatment

ContextDoxorubicin (DOX) is an anthracycline anticancer drug that can cause dose‐dependent cardiomyopathy and chronic heart failure. DOX cardiotoxicity has been attributed to excess production of ROS and genotoxicity that leads to cell death. AMPK is a kinase composed of α, β and γ subunits. AMPK has been proposed to modulate DOX‐induced cardiotoxicity, but the downstream mediators or effectors remain unclear. Connexin 43 (Cx43) is a gap junction protein abundantly expressed in the cardiomyocyte and is essential for heart function. Studies have suggested a role for Cx43 in DOX cardiotoxicity, but it remains unknown whether AMPK interacts with Cx43 to regulate cardiac response to DOX chemotherapy.ObjectiveTo determine the role of AMPK in the regulation of the Cx43 in response to DOX‐induced cardiotoxicity.MethodsH9c2 rat cardiomyocytes were seeded on 6‐well plates and cultured in DMEM with 6.5% fetal bovine serum. To investigate the role of AMPK, the cells were transfected with siRNAs targeting different AMPK isoforms using Lipofectamine RNAiMAX and Opti‐MEM I reduced serum medium. After 48 hours of transfection, half of the wells received 0.5 µM DOX treatment, and the other half received equal amounts of saline. Protein samples were collected 16 hours later using the Cell lysis buffer. Western blot analysis was performed to confirm the knockdown of AMPK isoforms and to determine the protein expression levels of Cx43.ResultsOur findings showed that siRNA transfections effectively reduced the protein levels of AMPK isoform a1 and a2, respectively, as indicated by the Western blot analysis. DOX treatment increased the expression levels of the Cx43 in cardiomyocytes. Also, knockdown (KD) of AMPKα1 isoform resulted in a similar increase in Cx43 expression levels as did DOX, but AMPKα2 KD did not significantly alter Cx43 levels, suggesting an AMPKa1 specific effect on Cx43 expression. Interestingly, AMPKα1 KD, together with DOX treatment, did not produce a synergistic effect to increase Cx43 expression levels further, suggesting the possibility that DOX might have elevated the Cx43 expression through its effect on AMPK.ConclusionOur results confirmed the previous studies showing that treatment of the cardiomyocytes with DOX increased the expression of Cx43. However, our investigations produced a novel finding that knocking down AMPKα1 also increased the Cx43 but did not enhance the effect of DOX on Cx43 expression, suggesting a role for AMPK in the pathway that regulates the Cx43 to mediate the DOX‐induced cardiotoxicity. Our investigations also showed an isoform‐specific effect of AMPK on Cx43 expression since only α1 but not α2 KD increased Cx43 levels. Whether the increase in Cx43 is due to increased gene expression or inhibited protein degradation remains to be determined. Further investigation is also warranted to elucidate the roles of other AMPK subunits or isoforms in regulating the Connexin 43 expression in the context of doxorubicin cardiotoxicity.

LncRNA NORAD Mediates the Proliferation and Apoptosis of Diffuse Large-B-Cell Lymphoma via Regulation of miR-345-3p/TRAF6 Axis

Diffuse large-B-cell lymphoma (DLBCL), as the most common subtype of B Cell Non-Hodgkin lymphoma (B-NHL), is one of the lymphoid malignancies with poor prognosis worldwide. Non-coding RNA activated by the DNA damage (NORAD), a novel identified lncRNA involved in the DNA repairment process, is reportedly to participate in carcinogenesis, and it is predicted to sponge miR-345-3p. However, LncRNA NORAD has never been investigated in DLBCL. To investigate the role of LncRNA NORAD and miR-345-3p in DLBCL cells and explore the underlying mechanisms. LncRNA NORAD and miR-345-3p levels were determined in the blood samples from patients with B-NHL. Human DLBCL cell lines DB and SU-DHL-4 were transfected with LncRNA NORAD small interfering RNA, miRNA-345-3p mimics, or miRNA-345-3p inhibitor using Lipofectamine RNAiMAX Reagent. Cell cycle, proliferation, and apoptosis were assessed in the transfected cells. Silencing of lncRNA NORAD and overexpression of miR-345-3p both inhibited cell proliferation, induced cell cycle arrest, and triggered apoptosis in DLBCL cells. Inhibition of miR-345-3p counteracted the suppression effects of LncRNA NORAD silencing on DLBCL progression. In addition, LncRNA NORAD shared the regulatory binding sites of miR-345-3p with TNF receptor associated factor 6 (TRAF6). Knockdown of LncRNA NORAD decreased the levels of TRAF6, simultaneously, resulted in deactivation of PI3K/Akt pathway in DLBCL cells. LncRNA NORAD regulated DLBCL cell growth and apoptosis via miR-345-3p/TRAF6/PI3K/Akt axis.

MiR-612, miR-637, and miR-874 can Regulate VEGFA Expression in Hepatocellular Carcinoma Cell Lines.

MicroRNAs (miRNAs) are short non-coding RNA molecules acting as important posttranscriptional gene and protein expression regulators in cancer. The study goal was to examine VEGFA (vascular endothelial growth factor A) expression in hepatocellular carcinoma (HCC) cell lines upon transfection miR-612, miR-637, or miR-874. Methods: MiR-612 mimics, miR-637 mimics, or miR-874 inhibitors were transfected using Lipofectamine RNAiMax in both HCC cell lines, HepG2 and HuH-7. Real-time PCR, Western blotting, and ELISA methods were used to evaluate VEGFA regulation by the miRNAs. Results: Gene and protein expression levels of VEGFA were down-expressed in both cell lines, HepG2 and HuH-7, transfected with miR-612 or miR-637. Transfection with miR-874 inhibitor showed an increase in VEGFA gene expression in HepG2 and HuH-7 cell lines; however, no regulation was observed on VEGFA protein expression by miR-874 inhibition. Correlation analysis between miRNAs and VEGFA protein expression showed that miR-637 and miR-874 expression present inversely correlated to VEGFA protein expression. Conclusions: VEGFA was down-regulated in response to hsa-miR-612 or hsa-miR-637 overexpression; however, the modulation of VEGFA by miR-874 was observed only at the gene expression and thus, needs further investigation.

Effective Transfection and Gene Silencing of Primary Murine Macrophages with Small Interfering RNA.

Transfection of murine primary macrophages to silence genes can be a challenging procedure because this cell type has developed mechanisms to evade cellular intrusion. The introduction of small interfering RNA (siRNA) encapsulated in liposomes to the cell to decrease gene expression is one of the methods that can be used to achieve gene silencing. There are different commercially available compounds to introduce siRNA into the cell, including Lipofectamine RNAiMAX and HiPerfect. The chapter will describe a method for gene silencing in mouse primary macrophages using liposome-based transfection of siRNA.

Development of Lipidoid Nanoparticles for siRNA Delivery to Neural Cells.

Lipidoid nanoparticles (LNPs) are the delivery platform in Onpattro, the first FDA-approved siRNA drug. LNPs are also the carriers in the Pfizer-BioNTech and Moderna COVID-19 mRNA vaccines. While these applications have demonstrated that LNPs effectively deliver nucleic acids to hepatic and muscle cells, it is unclear if LNPs could be used for delivery of siRNA to neural cells, which are notoriously challenging delivery targets. Therefore, the purpose of this study was to determine if LNPs could efficiently deliver siRNA to neurons. Because of their potential delivery utility in either applications for the central nervous system and the peripheral nervous system, we used both cortical neurons and sensory neurons. We prepared siRNA-LNPs using C12-200, a benchmark ionizable cationic lipidoid along with helper lipids. We demonstrated using dynamic light scattering that the inclusion of both siRNA and PEG-lipid provided a stabilizing effect to the LNP particle diameters and polydispersity indices by minimizing aggregation. We found that siRNA-LNPs were safely tolerated by primary dorsal root ganglion neurons. Flow cytometry analysis revealed that Cy5 siRNA delivered via LNPs into rat primary cortical neurons showed uptake levels similar to Lipofectamine RNAiMAX—the gold standard commercial transfection agent. However, LNPs demonstrated a superior safety profile, whereas the Lipofectamine-mediated uptake was concomitant with significant toxicity. Fluorescence microscopy demonstrated a time-dependent increase in the uptake of LNP-delivered Cy5 siRNA in a human cortical neuron cell line. Overall, our results suggest that LNPs are a viable platform that can be optimized for delivery of therapeutic siRNAs to neural cells.Graphical Supplementary InformationThe online version contains supplementary material available at 10.1208/s12248-021-00653-2.

USP10 exacerbates neointima formation by stabilizing Skp2 protein in vascular smooth muscle cells

The underlying mechanism of neointima formation remains unclear. Ubiquitin-specific peptidase 10 (USP10) is a deubiquitinase that plays a major role in cancer development and progression. However, the function of USP10 in arterial restenosis is unknown. Herein, USP10 expression was detected in mouse arteries and increased after carotid ligation. The inhibition of USP10 exhibited thinner neointima in the model of mouse carotid ligation. In vitro data showed that USP10 deficiency reduced proliferation and migration of rat thoracic aorta smooth muscle cells (A7r5) and human aortic smooth muscle cells (HASMCs). Mechanically, USP10 can bind to Skp2 and stabilize its protein level by removing polyubiquitin on Skp2 in the cytoplasm. The overexpression of Skp2 abrogated cell cycle arrest induced by USP10 inhibition. Overall, the current study demonstrated that USP10 is involved in vascular remodeling by directly promoting VSMC proliferation and migration via stabilization of Skp2 protein expression.

Abstract P498: Polycystin-1 Regulates Excitation-contraction Coupling In Atrial Cardiomyocytes

Patients with Autosomal Dominant Polycystic Kidney disease (ADPKD) have multiple cardiovascular manifestations, including increased susceptibility to arrhythmias. Mutations in polycystin-1 (PC1) encoding gene accounts for 85% cases of ADPKD, whereas mutations in polycystin-2 (PC2) only accounts for 15%. In kidney cells, PC1 interacts with PC2 to form a protein complex at the primary cilia to regulate calcium influx via PC2. However, cardiomyocytes are non-ciliated cells and the role of both PC1 and PC2 in atrial cardiomyocytes remains unknown. We have previously demonstrated that PC1 regulates action potentials and calcium handling to fine-tune ventricular cardiomyocyte contraction. Here, we hypothesize that PC1 regulates action potentials and calcium handling in atrial cardiomyocytes independent of PC2 actions. To test this hypothesis, we differentiated human induced pluripotent stem cells (iPSC) into atrial cardiomyocytes (iPSC-aCM) using previously published protocols. To determine the contribution of PC1/PC2 in atrial excitation-contraction coupling, protein expression was knocked down utilizing specific siRNA constructs, for each protein, or a universal control siRNA transfected using lipofectamine RNAiMAX. We measured action potentials using the potentiometric dye FluoVolt and intracellular calcium with Fura-2 AM or Fluo-4. Changes in fluorescence were monitored using a multiwavelength IonOptix system. iPSC-aCM were paced at 2 Hz to synchronize the beating pattern using field electrical stimulation. Our data shows that PC1 ablation significantly decreased action potential duration at 50% and 80% of repolarization, by 24% and 23%, respectively. Moreover, we observed that PC1 knockdown significantly reduced calcium transient amplitude elicited by field electrical stimulation without changes in calcium transient decay. Interestingly, PC2 knockdown did not modify calcium transients in atrial cardiomyocytes (iPSC-aCM). Our data suggest that PC1 regulates atrial excitation-contraction coupling independent of PC2 actions. This study warrants further investigation into atrial dysfunction in ADPKD patients with PC1 mutations.

An Aggregation-Induced Emission Optical Highlighter for the Studies of Endoplasmic Reticulum-Lipid Droplet Content Dynamics

An Aggregation-Induced Emission Optical Highlighter for the Studies of Endoplasmic Reticulum-Lipid Droplet Content Dynamics

CD36 Plays A Key Role As A Cell Cycle Regulator In Skeletal Muscle Cells

As a fatty acid transporter, CD36 plays an important role in regulating glucose and lipid metabolism. However, in addition to the regulation of skeletal muscle metabolism, whether it can regulate skeletal muscle cell cycle and proliferation is still unclear. PURPOSE: To investigate the role of CD36 in regulating skeletal muscle cell cycle. METHOD: Cells at 80%–90% confluence were differentiated, then transfected with siCtrl or siCD36 using Lipofectamine RNAiMAX when 80% ~ 90% of cells were in long shape. Skeletal muscle cells were harvested after 72 hours of transfection. The cell cycle of differentiated skeletal muscle cells was monitored by flow cytometry. Real-time fluorescent quantitative PCR was used to detect the cell cycle-related genes of skeletal muscle cells. Cyclin D1 protein level was determined by Western blot analysis. RESULT: Significant cell cycle arrest at G0/G1 phase occurred in the absence of CD36 (83.81% ± 0.59% vs. 53.25% ± 4.94%, p < 0.001), and fewer cells entered S phase(7.11% ± 0.82% vs. 36.49% ± 3.72%, p < 0.001). The mRNA expression levels of Mcm5, Orc1, cdkn1c and Skp2 increased significantly in CD36 deficiency (2.06% ± 0.17% vs. 1% ± 0.30%, p < 0.05, 1.82% ± 0.15% vs. 1% ± 0.17%, p < 0.05, 2.39% ± 0.37% vs. 1% ± 0.34%, p < 0.05, 2.05% ± 0.29% vs. 1% ± 0.35%, p < 0.05). The expression of Cyclin D1 in CD36 dysfunction group was decreased(83.31% ± 3.06% vs. 134.41% ± 6.57%, p < 0.01). CONCLUSION: Loss of CD36 leads to cell cycle arrest, implicating a promising target for normal progression of muscle progenitors from proliferation to differentiation. Supported by the National Natural Science Foundation of China (No. 32071172, 31600966).

Loss Of Cd36 Protects Skeletal Muscle Cells From PA-Induced Apoptosis By Enhancing Autophagy

Studies have shown that skeletal muscle mass was declined with diabetes and obesity. Skeletal muscle mass declines resulting in sarcopenia and metabolic diseases. CD36 is also reported to play a pivotal role in Type 2 Diabetes. Therefore, the apoptosis of skeletal muscle cells plays a vital role in maintaining the functional muscle mass of type 2 diabetes. PURPOSE: To investigate the protective effect of Fatty Acid Translocase (FAT/CD36) against PA-induced apoptosis. METHODS: Cells were differentiated when they reached 80%–90% confluence. Once the long shape occurred in 80%–90% cells, lipofectamine RNAiMAX was used to transfect siCtrl or siCD36.The whole term for knockdown is 72 h. Skeletal muscle cells were harvested after treatment with PA (200 μM) for 16 h. The apoptosis of differentiated skeletal muscle cells induced by PA treatment was monitored by flow cytometry. The gene expression level of endoplasmic reticulum stress-related genes was detected by QPCR. The protein expression level of autophagy-related genes was detected by Western blotting. The t-test was used as the statistical test. RESULTS: Compared with the PA-free culture medium group, skeletal muscle cells treated with PA had increased apoptosis (18.75% ± 1.25% vs. 12.74% ± 0.19%, p < 0.001). Whereas skeletal muscle cells treated with siCD36 transfection can resist apoptosis under PA and PA-free condition (15.86% ± 0.96% vs. 18.75% ± 1.25%, p < 0.05; 9.92% ± 0.37% vs. 12.74% ± 0.19%, p < 0.001) especially in the late stage (10.83% ± 0.49% vs. 13.4% ± 1.52%, p < 0.05; 6.18% ± 0.69% vs. 9.5% ± 0.15%, p < 0.01). The mRNA expression level of Grp78 and Ire1a were increased in CD36 deficiency group (1.23 ± 0.09 vs. 1 ± 0.05, p < 0.05; 1.25 ± 0.07 vs. 1 ± 0.05, p < 0.05). The protein expression level of LC3-II, Beclin1 were significantly increased in CD36 deficiency group (201.71 ± 3.13 vs. 160.40 ± 6.76, p < 0.05, 193.84 ± 2.92 vs. 176.94 ± 1.41, p < 0.05). CONCLUSIONS: CD36, as a signaling molecule, can activate the autophagy pathway through the endoplasmic reticulum, thereby attenuating apoptosis in PA-stimulated skeletal muscle cells, implicating a promising target for metabolic diseases. Supported by the National Natural Science Foundation of China (No. 32071172, 31600966).

MiR-139-5p mediates the palmitate-induced inhibition of insulin secretion by targeting neuronal pentraxin 1 in INS-1 cells.

High fatty acid reduces insulin secretion in pancreatic β-cells and miR-139-5p is increased in diabetic pancreatic tissues and induces islet β-cell apoptosis. However, to date, there is no study exploring whether or not miR-139-5p is involved in high fatty acid-induced insulin secretion. In the present study, INS-1 cells were exposed to different concentrations (0.1, 0.2, and 0.4 mM) of palmitate for different time periods (12, 24, and 48 h). The expression levels of miR-139-5p and neuronal pentraxin 1 (NPTX1) were evaluated by real-time PCR and western blot analysis. The regulation of NPTX1 by miR-139-5p was examined by luciferase assay. Cell transfection was conducted using Lipo8000 or Lipofectamine RNAiMAX. Potassium or glucose-stimulated insulin secretion levels were used to verify the function of miR-139-5p or NPTX1 in insulin secretion. Insulin secretion levels were detected by radioimmunoassay. We found that miR-139-5p was increased in INS-1 cells stimulated with palmitate. In addition, miR-139-5p was also elevated in islets of high-fat diet-fed mice and db/db mice compared to those in islets of normal diet-fed mice and wild-type mice. Knockdown of miR-139-5p could reverse high fatty acid-induced insulin secretion defects in INS-1 cells. Furthermore, we demonstrated that NPTX1 is a target of miR-139-5p. miR-139-5p mediated palmitate-induced insulin secretion defects by targeting NPTX1. Moreover, palmitate treatment declined the expression of NPTX1 and the NPTX1 expression was also decreased in islets of high-fat diet-fed mice and db/db mice. Impaired NPTX1 expression is involved in fatty acid-induced insulin secretion defects. Collectively, our results illustrate that the induction of β-cell insulin secretion defects by fatty acids is mediated, at least in part, by miR-139-5p via downregulation of NPTX1 expression.

P041 CDKN2B-AS1 (ANRIL) expression is decreased in Inflammatory Bowel Disease epithelia and in Celiac, and its reduction is linked with induced cells proliferation

Abstract Background Long non-coding RNAs (lncRNAs) have attenuated expression in several immune-mediated disorders. Using mRNAseq of intestinal biopsies, we identified a widespread dysregulation of 459 lncRNAs in the ileum of treatment-naïve pediatric Crohn Disease (CD) patients. We noted that large fraction of downregulated lncRNAs were correlated with epithelial functions. CDKN2B-AS1 (ANRIL) is one of the top most down-regulated lncRNA in CD, and showed decreased expression in Ulcerative Colitis (UC) colon tissues in recent studies. Methods Transcriptomics data is used to evaluate CDKN2B-AS1 expression in mucosal biopsies datasets and in gut epithelia. siRNA oligonucleotides targeting most CDKN2B-AS1 transcripts using Lipofectamine RNAiMAX is used to modulate CDKN2B-AS1 function, and RT-PCR to evaluate mRNA expression. xCELLigence system with gold microelectrodes in plate base is used to measure the impedance as an indicator for cell index. Results CDKN2B-AS1 is down-regulated in bulk mucosal biopsies obtained from CD ileum [fold change (FC) -8, corrected p=1.6E-5], in UC rectum (FC -9.4, corrected p=3.9E-18), and in celiac duodenum (FC -2.3, corrected p=0.03) in comparison to controls. CDKN2B-AS1 is detected under basal conditions in HT-29 cells. Two sets of CDKN2B-AS1 siRNA oligonucleotides (targeting most transcripts) achieved up to 60% reduction in CDKN2B-AS1 expression in HT-29 cells (p=1E-04) as confirmed by RT-PCR using two sets of primers. CDKN2B-AS1 reduction significantly increased cell index as measured by xCELLigence (doubled the index, p=1.7E-03). mRNAseq of the CDKN2B-AS1 reduced HT-29, showed reduction of the tumor suppressor gene APC in CDKN2B-AS1 siRNA treated cells (FC=-1.75, p=0.04) and of TGFBR2 (FC=-1.75, p=0.04). In contrast, reduction of CDKN2B-AS1 resulted in increase in WNT11 (FC=2.1, p=0.02) and TGFB1 (FC=1.9, p=0.04), and induction of the replication associated topoisomerase TOP1MT (FC=2.7, p=0.001). We confirmed these mRNAseq results using RT-PCR. Finally, mimicking inflammation by treating HT-29 with IL1β and LPS, reduced CDKN2B-AS1 expression (by 70%, p=6.3E-04) and doubled the cell index (p=1.8E-03). Conclusion We detected reduced CDKN2B-AS1 expression in three inflammatory disease affecting the gut in different location along the GI tract. Using HT-29 model system we were able to show, as was previously shown, an increase in cell index in CDKN2B-AS1 siRNA treated cells. We supplement those showing effect on down-stream genes that may be relevant in controlling cell proliferation. We further show that upon inflammatory triggering of HT-29 cells, CDKN2B-AS1 expression is reduced and cell index is increased, which may suggest a potential role in epithelial renewal in inflammation.

Rabies Prophylactic and Treatment Options: An In Vitro Study of siRNA- and Aptamer-Based Therapeutics.

If the goal of eliminating dog-mediated human rabies by 2030 is to be achieved, effective mass dog vaccination needs to be complemented by effective prophylaxis for individuals exposed to rabies. Aptamers and short-interfering RNAs (siRNAs) have been successful in therapeutics, but few studies have investigated their potential as rabies therapeutics. In this study, siRNAs and aptamers—using a novel selection method—were developed and tested against rabies virus (RABV) in a post-infection (p.i.) scenario. Multiple means of delivery were tested for siRNAs, including the use of Lipofectamine and conjugation with the developed aptamers. One siRNA (N53) resulted in an 80.13% reduction in viral RNA, while aptamer UPRET 2.03 demonstrated a 61.3% reduction when used alone at 2 h p.i. At 24 h p.i., chimera UPRET 2.03-N8 (aptamer-siRNA) resulted in a 36.5% inhibition of viral replication. To our knowledge, this is the first study using siRNAs or aptamers that (1) demonstrated significant inhibition of RABV using an aptamer, (2) tested Lipofectamine RNAi-Max as a means for delivery, and (3) produced significant RABV inhibition at 24 h p.i. This study serves as a proof-of-concept to potentially use aptamers and siRNAs as rabies immunoglobulin (RIG) replacements or therapeutic options for RABV and provides strong evidence towards their further investigation.

Mechanism of NO Decay in Vascular Smooth Muscle Cells: Role of Cytoglobin and Identification of its Cellular Reducing System

Background In smooth muscle, cytoglobin (Cygb) functions as a potent nitric oxide (NO) dioxygenase and regulates NO metabolism and vascular tone. However, major questions remain regarding which cellular reducing systems regulate Cygb-mediated NO metabolism. Therefore, we performed studies to assess the intracellular concentrations of Cygb and its reducing systems in vascular smooth muscle cells (SMCs), and their role in the process of NO decay. Methods Cygb and its reducing systems, cytochrome B5 reductase (B5R), cytochrome B5 (B5) and cytochrome P450 reductase (CPR) were measured in aortic SMCs. Murine aortic smooth muscle cells (SMCs) were purchased from American Type Culture Collection (ATCC; CRL-2797™) and passaged. For depleting Cygb, B5R or B5, siRNAs were used. SMCs were transfected with Cygb siRNA, B5R siRNA, B5 siRNA or CPR siRNA using Lipofectamine RNAiMAX (Invitrogen). The rate of NO metabolism by normal SMCs of different cell numbers was assessed using a Clark-type NO electrode (NOCHM-4, WPI) utilizing two ports on the side wall of a four-port water-jacketed electrochemical chamber (NOCHM-4, WPI) and additionally another oxygen electrode was placed through second port on the side wall of the chamber. For protein assays, Cygb, B5R and B5 were expressed and purified using reported procedures. Quantitative immunoblotting was used to estimate the cellular concentrations of Cygb and each reducing system protein from comparison to standards of known concentration for each purified protein. Results Intracellular Cygb concentration was estimated as 3.5 µM, while B5R, B5, and CPR were 0.88, 0.38 and 0.15 µM, respectively. NO decay in SMCs was measured following bolus addition of 1 µM NO to air-equilibrated cells. The NO dioxygenation rate (VNO) with 3.5 x 106 cells•ml-1 was 12.7 ± 0.3 nM•s-1. siRNA-mediated knockdown experiments indicated that ~78% of NO metabolism in SMCs was Cygb-dependent. Of this, ~87 % was B5R- and B5-dependent. CPR knockdown resulted in a small decrease in VNO, while depletion of ascorbate had no effect. Kinetic analysis of VNO for the B5R/B5/Cygb system with variation of B5 or B5R concentrations from their SMC levels showed that VNO exhibits apparent Michaelis-Menten behavior for B5 and B5R. In contrast, linear variation was seen with change in Cygb concentration. Conclusions B5R/B5 was demonstrated to be the major reducing system supporting Cygb-mediated NO metabolism in SMCs and studies were performed to experimentally model and predict the alterations of VNO with changes in cellular B5R/B5/Cygb levels.

Down‐regulation of Ca 2+ ‐Activated K + Channel K Ca 3.1 in mouse preosteoblast cells treated with vitamin D receptor agonists

Background Bone tissue is a dynamic and living organ, constantly renewed through the process of bone remodeling. The intricate balance between bone-forming and bone-resorbing activity is vital for maintenance of bone homeostasis. Vitamin D (VD) plays pivotal roles in calcium homeostasis, mineral metabolism, and bone development indirectly via control calcium absorption in the intestine and reabsorption in the kidney. However, several in vitro studies showed that VD can directly suppress the cell proliferation of mouse osteoblasts. The direct effect of VD receptor (VDR) in osteoblasts is poorly understood. The intermediate-conductance Ca2+-activated K+ channel KCa3.1 regulates intracellular Ca2+ signaling and is associated with cell proliferation in various non-excitable cells including preosteoblasts. In this study, we examined the effects of treatments with VDR agonists on the expression and activity of KCa3.1 in mouse preosteoblast MC3T3-E1 cells. Methods Intracellular Ca2+ changes were measured in MC3T3-E1 cells by Ca2+ indicator, fura-2/AM. Cell viability was measured by a WST-1 assay. MC3T3-E1 cells were transiently transfected with HDAC2, Fra-1, and VDR Silencer Select pre-designed siRNAs using a Lipofectamine RNAiMAX reagent. The Silencer Select negative control No.1 siRNA was used as a control. Results Treatments with calcitriol, a VDR agonist, for 48 h markedly decreased the expression levels of KCa3.1 transcripts and proteins in MC3T3-E1 cells, resulting in the significant inhibition of Ca2+ rises induced by DCEBIO, a specific KCa3.1 activator. Treatments with calcitriol also significantly decreased the expression of several transcriptional regulators of KCa3.1 such as histone deacetylase 2 (HDAC2) and Fra-1 composed of activation protein 1. In addition, the pharmacological blockade of HDAC with vorinostat, a pan-HDAC inhibitor, significantly decreased the expression of KCa3.1. The knockdown of Fra-1 using siRNA decreased the expression of KCa3.1 mRNA without the suppression of HDAC2 mRNA. The knockdown of VDR also recovered the expression of KCa3.1, HDAC2 and Fra-1 in calcitriol-treated MC3T3-E1 cells. Conclusion Our results suggest that KCa3.1 is a new downstream target of VDR signaling and the down-regulation of KCa3.1 through the transcriptional repression of KCa3.1 contribute, at least partly, to the antiproliferative effects of VDR agonists in mouse pre-osteoblasts.