Antifibrotic and Pro-regenerative Effects of SMAD3 siRNA and Collagen I mRNA-Loaded Lipid Nanoparticles in Human Tenocytes

Tendinopathy involves the inflammation and degeneration of the tendon due to repetitive strain injury. Current treatments primarily target inflammation resolution, yet they do not aim at tissue regeneration. In this study, a microfluidics approach is harnessed to develop a platform of lipid nanoparticles (LNPs) loaded simultaneously with SMAD3 siRNA and collagen I mRNA, aiming to explore its potential dual antifibrotic and regenerative effects in human tenocytes. The developed LNPs displayed size homogeneity and colloidal stability and exhibited high cytocompatibility in human tenocytes. Moreover, LNPs allowed for efficient uptake and transfection efficiency of the RNAs. In the in vitro efficacy studies, the gene expression and production of SMAD3 and collagen I were tested by real-time quantitative chain polymerase reaction and immuno- and intracellular staining, revealing collagen I production enhancement, SMAD3 inhibition, and modulation of other tendon repair factors by the LNPs. Overall, the potential of this platform of RNA-loaded LNPs to be used as a dual therapeutic approach to prevent fibrosis and promote tissue remodeling in late stages of tendon diseases was confirmed.

STIM2 is involved in the regulation of apoptosis and the cell cycle in normal and malignant monocytic cells

Calcium is a ubiquitous messenger that regulates a wide range of cellular functions, but its involvement in the pathophysiology of acute myeloid leukemia (AML) is not widely investigated. Here, we identified, from an analysis of The Cancer Genome Atlas and genotype-tissue expression databases, stromal interaction molecule 2 (STIM2) as being highly expressed in AML with monocytic differentiation and negatively correlated with overall survival. This was confirmed on a validation cohort of 407 AML patients. We then investigated the role of STIM2 in cell proliferation, differentiation, and survival in two leukemic cell lines with monocytic potential and in normal hematopoietic stem cells. STIM2 expression increased at the RNA and protein levels upon monocyte differentiation. Phenotypically, STIM2 knockdown drastically inhibited cell proliferation and induced genomic stress with DNA double-strand breaks, as shown by increased levels of phosphorylate histone H2AXγ (p-H2AXγ), followed by activation of the cellular tumor antigen p53 pathway, decreased expression of cell cycle regulators such as cyclin-dependent kinase 1 (CDK1)-cyclin B1 and M-phase inducer phosphatase 3 (CDC25c), and a decreased apoptosis threshold with a low antiapoptotic/proapoptotic protein ratio. Our study reports STIM2 as a new actor regulating genomic stability and p53 response in terms of cell cycle and apoptosis of human normal and malignant monocytic cells.

Low-level Cu-fortification of bovine lactoferrin: Focus on its effect on in vitro anti-inflammatory activity in LPS-stimulated macrophages

Bovine lactoferrin (LF) per 1 g was reacted with 0.16, 0.32, and 0.64 mg CuCl₂ to reach 10%, 20%, and 40% copper-saturation, respectively, aiming to assess their anti-inflammatory activities to lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages. The macrophages treated with CuCl₂ at 0.051 μg/mL dose did not have obvious change in cell viability, lactate dehydrogenase (LDH) release, and intracellular reactive oxygen species (ROS) production. However, LF and Cu-fortified LF products (10-80 μg/mL doses) mostly showed inhibitory effects on the stimulated macrophages dose-dependently. Moreover, Cu-fortified LF products of lower Cu-fortifying levels at lower doses exerted weaker inhibition on the stimulated macrophages than LF, leading to higher cell viability but decreased LDH release. Meanwhile, LF and Cu-fortified LF products at 10 and 20 μg/mL doses showed different activities to the stimulated cells, via partly decreasing or increasing the production of inflammatory mediators namely prostaglandin E₂ (PGE₂), nitric oxide, tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), IL-1β, and ROS production, depending on the used Cu-fortifying and dose levels. Compared with LF, Cu-fortified LF product (Cu-fortifying level of 0.16 mg/g LF) at 10 μg/mL dose showed enhanced inhibition on the production of PGE₂, ROS, IL-1β, and TNF-α, evidencing increased anti-inflammatory activity. However, the inhibition of Cu-fortified LF product (Cu-fortifying level of 0.32 mg/g LF) at 20 μg/mL dose on the production of these inflammatory mediators was mostly reduced. It is thus proposed that both Cu-fortifying and dose levels could affect LF's anti-inflammatory activity in LPS-stimulated macrophages, while the Cu-fortifying level of LF could govern activity change.

Trifaceted Mickey Mouse Amphiphiles for Programmable Self-Assembly, DNA Complexation and Organ-Selective Gene Delivery

Instilling segregated cationic and lipophilic domains with an angular disposition in a trehalose-based trifaceted macrocyclic scaffold allows engineering patchy molecular nanoparticles leveraging directional interactions that emulate those controlling self-assembling processes in viral capsids. The resulting trilobular amphiphilic derivatives, featuring a Mickey Mouse architecture, can electrostatically interact with plasmid DNA (pDNA) and further engage in hydrophobic contacts to promote condensation into transfectious nanocomplexes. Notably, the topology and internal structure of the cyclooligosaccharide/pDNA co-assemblies can be molded by fine-tuning the valency and characteristics of the cationic and lipophilic patches, which strongly impacts the transfection efficacy in vitro and in vivo. Outstanding organ selectivities can then be programmed with no need of incorporating a biorecognizable motif in the formulation. The results provide a versatile strategy for the construction of fully synthetic and perfectly monodisperse nonviral gene delivery systems uniquely suited for optimization schemes by making cyclooligosaccharide patchiness the focus.

In vitro anti-inflammatory potential of marine macromolecules cross-linked bio-composite scaffold on LPS stimulated RAW 264.7 macrophage cells for cartilage tissue engineering applications

Biomaterials serve as an integral component of tissue engineering. They are designed to provide architectural framework of native extracellular matrix so as to encourage cell growth and eventual tissue regeneration. Naturally occurring biopolymers as scaffolds offer options for cartilage tissue engineering due to anti-inflammatory, biocompatibility, biodegradability, low toxicity of degradation by-products and plasticity in processing into a variety of material formats. Here we studied in vitro anti-inflammatory potential of marine macromolecules cross-linked bio-composite scaffold composed of hydroxyapatite, alginate, chitosan and fucoidan named as HACF on LPS stimulated RAW 264.7 macrophage cells. The effects of HACF on the viability of RAW264.7 cells, nitrite level, intracellular ROS as well as the mRNA levels of NF-κB, iNOS, COX-2, TNF-α, IL-1β and IL-6 were examined in LPS induced RAW264.7 macrophage cells. The results revealed that HACF hydrogel scaffold exerts anti-inflammatory effect by inhibiting the production of ROS, suppress NF-kB translocation to the nucleus and thereby inhibiting the production of inflammatory mediators. Hence, our results confirm that HACF has a strong anti-oxidant capacity to inhibit inflammation associated gene expression by suppressing NF-kB signaling pathway. It clearly reveals the anti-oxidant and anti-inflammatory effect of HACF hydrogel scaffold on LPS induced RAW 264.7 cells.

Capsule carbohydrate structure determines virulence in Acinetobacter baumannii

Acinetobacter baumannii is a highly antibiotic-resistant bacterial pathogen for which novel therapeutic approaches are needed. Unfortunately, the drivers of virulence in A. baumannii remain uncertain. By comparing genomes among a panel of A. baumannii strains we identified a specific gene variation in the capsule locus that correlated with altered virulence. While less virulent strains possessed the intact gene gtr6, a hypervirulent clinical isolate contained a spontaneous transposon insertion in the same gene, resulting in the loss of a branchpoint in capsular carbohydrate structure. By constructing isogenic gtr6 mutants, we confirmed that gtr6-disrupted strains were protected from phagocytosis in vitro and displayed higher bacterial burden and lethality in vivo. Gtr6+ strains were phagocytized more readily and caused lower bacterial burden and no clinical illness in vivo. We found that the CR3 receptor mediated phagocytosis of gtr6+, but not gtr6-, strains in a complement-dependent manner. Furthermore, hypovirulent gtr6+ strains demonstrated increased virulence in vivo when CR3 function was abrogated. In summary, loss-of-function in a single capsule assembly gene dramatically altered virulence by inhibiting complement deposition and recognition by phagocytes across multiple A. baumannii strains. Thus, capsular structure can determine virulence among A. baumannii strains by altering bacterial interactions with host complement-mediated opsonophagocytosis.

Pneumocystis carinii Major Surface Glycoprotein Dampens Macrophage Inflammatory Responses to Fungal β-Glucan

BACKGROUND

Pneumocystis major surface glycoprotein (Msg) is a 120-kD surface protein complex on the organism with importance in adhesion and immune recognition. In this study, we show that Msg significantly impairs tumor necrosis factor (TNF)-α secretion by macrophages induced by Saccharomyces cerevisiae and Pneumocystis carinii (Pc) β-glucans.

METHODS

Major surface glycoprotein was shown to greatly reduce β-glucan-induced Dectin-1 immunoreceptor tyrosine-based activating motif (ITAM) phosphorylation. Major surface glycoprotein also down regulated Dectin-1 receptor messenger ribonucleic acid (mRNA) expression in the macrophages. It is interesting that Msg incubation with macrophages resulted in significant mRNA upregulation of both C-type lectin receptors (CLR) Mincle and MCL in Msg protein presence alone but to even greater amounts in the presence of Pc β-glucan.

RESULTS

The silencing of MCL and Mincle resulted in TNF-α secretions similar to that of macrophages treated with Pneumocystis β-glucan alone, which is suggestive of an inhibitory role for these 2 CLRs in Msg-suppressive effects on host cell immune response.

CONCLUSIONS

Taken together, these data indicate that the Pneumocystis Msg surface protein complex can act to suppress host macrophage inflammatory responses to the proinflammatory β -glucan components of the organisms.

RIC3, the cholinergic anti-inflammatory pathway, and neuroinflammation

Nicotinic acetylcholine receptors (nAChRs) are ligand-gated ion channels having many functions including inflammation control, as part of the cholinergic anti-inflammatory pathway. Genome wide association studies implicated RIC3, a chaperone of nAChRs, in multiple sclerosis (MS), a neuroinflammatory disease. To understand the involvement of RIC3 in inflammatory diseases we examined its expression, regulation, and function in activated immune cells. Our results show that immune activation leads to dynamic changes in RIC3 expression, in a mouse model of MS and in human lymphocytes and macrophages. We also show similarities in the expression dynamics of RIC3 and CHRNA7, encoding for the α7 nAChR subunit. Homomeric α7 nAChRs were shown to mediate the anti-inflammatory effects of cholinergic agonists. Thus, similarity in expression dynamics between RIC3 and CHRNA7 is suggestive of functional concordance. Indeed, siRNA mediated silencing of RIC3 in a mouse macrophage cell line eliminates the anti-inflammatory effects of cholinergic agonists. Furthermore, we show increased average expression of RIC3 and CHRNA7 in lymphocytes from MS patients, and a strong correlation between expression levels of these two genes in MS patients but not in healthy donors. Together, our results are consistent with a role for RIC3 and for the mechanisms regulating its expression in inflammatory processes and in neuroinflammatory diseases.

Anti-Inflammatory Effects of Hypophyllanthin and Niranthin Through Downregulation of NF-κB/MAPKs/PI3K-Akt Signaling Pathways

Hypophyllanthin (HYP) and niranthin (NIR) are major lignans in Phyllanthus spp. and have been shown to possess strong anti-inflammatory activity. In this study, we investigated the anti-inflammatory effects and the underlying molecular mechanisms of HYP and NIR in in vitro cellular model of LPS-induced U937 macrophages. The effects of HYP and NIR on the production of prostaglandin E₂ (PGE₂), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) were measured by using ELISA, Western blot, and qRT-PCR. The expressions of signaling molecules related to nuclear factor-kappa B (NF-κB), mitogen-activated protein kinases (MAPKs), and phosphatidylinositol 3'-kinase-Akt (PI3K-Akt) signaling pathways were examined. The role of NF-κB, MAPKs, and Akt signaling pathways was confirmed by using specific inhibitors (BAY 11-7082, U0126, SB202190, SP600125, and LY294002) mediated suppression of TNF-α and COX-2 production. HYP and NIR significantly inhibited the protein and gene levels of COX-2 as well as the downstream signaling products of PGE₂, TNF-α, and IL-1β. HYP and NIR also suppressed the inhibitors of kappa B (IκB), IkB kinases (Ikkα/β), NF-κB phosphorylation, and IκB degradation. HYP suppressed the phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK), and p38 while NIR only suppressed JNK and ERK but did not have effect on p38. These results demonstrate that HYP and NIR downregulated COX-2, TNF-α, and IL-1β gene expressions in U937 macrophages by interfering with the activation of NF-κB, MAPKs, and Akt. In conclusion, these lignans have potential to be developed as anti-inflammatory agents targeting the NF-κB, MAPK, and PI3K-Akt pathways.

Mycobacterium tuberculosis Controls Phagosomal Acidification by Targeting CISH-Mediated Signaling

Pathogens have evolved a range of mechanisms to counteract host defenses, notably to survive harsh acidic conditions in phagosomes. In the case of Mycobacterium tuberculosis, it has been shown that regulation of phagosome acidification could be achieved by interfering with the retention of the V-ATPase complexes at the vacuole. Here, we present evidence that M. tuberculosis resorts to yet another strategy to control phagosomal acidification, interfering with host suppressor of cytokine signaling (SOCS) protein functions. More precisely, we show that infection of macrophages with M. tuberculosis leads to granulocyte-macrophage colony-stimulating factor (GM-CSF) secretion, inducing STAT5-mediated expression of cytokine-inducible SH2-containing protein (CISH), which selectively targets the V-ATPase catalytic subunit A for ubiquitination and degradation by the proteasome. Consistently, we show that inhibition of CISH expression leads to reduced replication of M. tuberculosis in macrophages. Our findings further broaden the molecular understanding of mechanisms deployed by bacteria to survive.

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M. tuberculosis interferes with host pathways to control vacuolar acidification

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Infection induces the expression of host CISH and recruitment to the phagosome

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CISH triggers the degradation of H⁺-V-ATPase via SOCS box-mediated ubiquitination

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This defense mechanism complements previous schemes relying on virulence factors

Functional Genomics in Murine Macrophages

In this chapter, we describe methods for functional genomics studies in mouse macrophages. In particular, we describe complementary methods for gene inhibition using RNA interference (RNAi) and gene overexpression. These methods are readily amenable to medium- and high-throughput functional genomics investigations. These complementary loss-of-function and gain-of-function genomic approaches provide a rapid means of investigating the function of candidate genes prior to initiating more cumbersome studies in vivo.

Rock the nucleus: significantly enhanced nuclear membrane permeability and gene transfection by plasmonic nanobubble induced nanomechanical transduction

Nanomechanical transduction increases permeability of the nuclear membrane and facilitates nuclear uptake of macromolecules that would otherwise not enter the nucleus.

Aspherical, Nanostructured Microparticles for Targeted Gene Delivery to Alveolar Macrophages

Introducing novel shapes to particulate carrier systems adds unique features to modern drug and gene delivery. Depending on the route of administration, particle geometry can influence deposition and fate within biological environments. In this work, a template-assisted engineering technique is applied, providing full control of size and shape in the preparation of aspherical, nanostructured microparticles. Based on the interconnection of nanoparticles, stabilized by a functional layer-by-layer (LbL) coating, the resulting cylindrical micrometer architecture is especially qualified for pulmonary delivery. Designed as gene delivery system, plasmid-DNA (pCMV-luciferase) and branched polyethylenimine are used to reach both structural integrity of the carrier system and delivery of genes into the cells of interest. Due to their size, particles are exclusively taken up by phagocytes, which also adds a targeting effect to the introduced system. The luciferase expression is demonstrated in macrophages showing increasing levels over a time period of at least 7 d. Furthermore, it is shown for the first time that the expression is depending on the LbL design. From in vivo experiments, corresponding luciferase expression is observed in mice alveolar macrophages. Combining site specific transport with the possibility of genetically engineering immunocompetent phagocytes, the presented system offers promising potential to improve applications for cell-based immunotherapy.

Silencing CCR2 in Macrophages Alleviates Adipose Tissue Inflammation and the Associated Metabolic Syndrome in Dietary Obese Mice

Adipose tissue macrophage (ATM)-mediated inflammation is a key feature contributing to the adverse metabolic outcomes of dietary obesity. Recruitment of macrophages to obese adipose tissues (AT) can occur through the engagement of CCR2, the receptor for MCP-1 (monocyte chemoattractant protein-1), which is expressed on peripheral monocytes/macrophages. Here, we show that i.p. administration of a rabies virus glycoprotein-derived acetylcholine receptor-binding peptide effectively delivers complexed siRNA into peritoneal macrophages and ATMs in a mouse model of high-fat diet-induced obesity. Treatment with siRNA against CCR2 inhibited macrophage infiltration and accumulation in AT and, therefore, proinflammatory cytokines produced by macrophages. Consequently, the treatment significantly improved glucose tolerance and insulin sensitivity profiles, and also alleviated the associated symptoms of hepatic steatosis and reduced hepatic triglyceride production. These results demonstrate that disruption of macrophage chemotaxis to the AT through cell-targeted gene knockdown strategies can provide a therapeutic intervention for obesity-related metabolic diseases. The study also highlights a siRNA delivery approach for targeting specific monocyte subsets that contribute to obesity-associated inflammation without affecting the function of other tissue-resident macrophages that are essential for host homeostasis and survival.

A Perspective on the Future of High-Throughput RNAi Screening: Will CRISPR Cut Out the Competition or Can RNAi Help Guide the Way?

For more than a decade, RNA interference (RNAi) has brought about an entirely new approach to functional genomics screening. Enabling high-throughput loss-of-function (LOF) screens against the human genome, identifying new drug targets, and significantly advancing experimental biology, RNAi is a fast, flexible technology that is compatible with existing high-throughput systems and processes; however, the recent advent of clustered regularly interspaced palindromic repeats (CRISPR)-Cas, a powerful new precise genome-editing (PGE) technology, has opened up vast possibilities for functional genomics. CRISPR-Cas is novel in its simplicity: one piece of easily engineered guide RNA (gRNA) is used to target a gene sequence, and Cas9 expression is required in the cells. The targeted double-strand break introduced by the gRNA-Cas9 complex is highly effective at removing gene expression compared to RNAi. Together with the reduced cost and complexity of CRISPR-Cas, there is the realistic opportunity to use PGE to screen for phenotypic effects in a total gene knockout background. This review summarizes the exciting development of CRISPR-Cas as a high-throughput screening tool, comparing its future potential to that of well-established RNAi screening techniques, and highlighting future challenges and opportunities within these disciplines. We conclude that the two technologies actually complement rather than compete with each other, enabling greater understanding of the genome in relation to drug discovery.

Acoustic Liquid Handling for Rapid siRNA Transfection Optimization

Gene knockdown by small interfering RNA (siRNA) has been used extensively to investigate the function of genes in targeted and genome-wide studies. One of the primary challenges of siRNA studies of any scale is to achieve sufficient gene knockdown to produce the biological changes that lead to measurable phenotypes. Reverse, lipid-based transfection efficiency minimally requires the optimization of the following parameters: cell number, knockdown duration, siRNA oligonucleotide concentration, type/brand of transfection lipid, and transfection lipid concentration. In this study, we describe a methodology to utilize the flexibility and low-volume range of the Echo acoustic liquid handler to rapidly screen a matrix of transfection conditions. The matrix includes six different transfection lipids from three separate vendors across a broad range of concentrations. Our results validate acoustic liquid transfer for the delivery of siRNAs and transfection reagents. Finally, this methodology is applied to rapidly optimize transfection conditions across many tissue culture cell lines derived from various originating tissues.

Using RNA-interference to investigate the innate immune response in mouse macrophages

Macrophages are key phagocytic innate immune cells. When macrophages encounter a pathogen, they produce antimicrobial proteins and compounds to kill the pathogen, produce various cytokines and chemokines to recruit and stimulate other immune cells, and present antigens to stimulate the adaptive immune response. Thus, being able to efficiently manipulate macrophages with techniques such as RNA-interference (RNAi) is critical to our ability to investigate this important innate immune cell. However, macrophages can be technically challenging to transfect and can exhibit inefficient RNAi-induced gene knockdown. In this protocol, we describe methods to efficiently transfect two mouse macrophage cell lines (RAW264.7 and J774A.1) with siRNA using the Amaxa Nucleofector 96-well Shuttle System and describe procedures to maximize the effect of siRNA on gene knockdown. Moreover, the described methods are adapted to work in 96-well format, allowing for medium and high-throughput studies. To demonstrate the utility of this approach, we describe experiments that utilize RNAi to inhibit genes that regulate lipopolysaccharide (LPS)-induced cytokine production.

Mycobacterial toxin induces analgesia in buruli ulcer by targeting the angiotensin pathways

Mycobacterium ulcerans, the etiological agent of Buruli ulcer, causes extensive skin lesions, which despite their severity are not accompanied by pain. It was previously thought that this remarkable analgesia is ensured by direct nerve cell destruction. We demonstrate here that M. ulcerans-induced hypoesthesia is instead achieved through a specific neurological pathway triggered by the secreted mycobacterial polyketide mycolactone. We decipher this pathway at the molecular level, showing that mycolactone elicits signaling through type 2 angiotensin II receptors (AT2Rs), leading to potassium-dependent hyperpolarization of neurons. We further validate the physiological relevance of this mechanism with in vivo studies of pain sensitivity in mice infected with M. ulcerans, following the disruption of the identified pathway. Our findings shed new light on molecular mechanisms evolved by natural systems for the induction of very effective analgesia, opening up the prospect of new families of analgesics derived from such systems.

A high content assay to assess cellular fitness

A universal process in experimental biology is the use of engineered cells; more often, stably or transiently transfected cells are generated for the purpose. Therefore, it is important that cell health assessment is conducted to check for stress mediated by induction of heat shock proteins (Hsps). For this purpose, we have developed an integrated platform that would enable a direct assessment of transfection efficiency (TE) combined with cellular toxicity and stress response. We make use of automated microscopy and high content analysis to extract from the same well a multiplexed readout to assess and determine optimal chemical transfection conditions. As a proof of concept, we investigated seven commercial reagents, in a matrix of dose and time, to study transfection of an EGFP DNA plasmid into HeLa cells and their consequences on health and fitness; where we scored for cellular proliferation, EGFP positive cells, and induction of Hsp10 and Hsp70 as makers of stress responses. FuGENE HD emerged as the most optimal reagent with no apparent side effects suitable for performing microtiter based miniaturized transfection for both chemical and RNAi screening. In summary, we report on a high content assay method to assess cellular overall fitness upon chemical transfection.

Innate host defense requires TFEB-mediated transcription of cytoprotective and antimicrobial genes

Animal host defense against infection requires the expression of defense genes at the right place and the right time. Understanding such tight control of host defense requires the elucidation of the transcription factors involved. By using an unbiased approach in the model Caenorhabditis elegans, we discovered that HLH-30 (known as TFEB in mammals) is a key transcription factor for host defense. HLH-30 was activated shortly after Staphylococcus aureus infection, and drove the expression of close to 80% of the host response, including antimicrobial and autophagy genes that were essential for host tolerance of infection. TFEB was also rapidly activated in murine macrophages upon S. aureus infection and was required for proper transcriptional induction of several proinflammatory cytokines and chemokines. Thus, our data suggest that TFEB is a previously unappreciated, evolutionarily ancient transcription factor in the host response to infection.

Polycationic nanoparticles for siRNA delivery: comparing ARGET ATRP and UV-initiated formulations

In this work, we develop and evaluate polycationic nanoparticles for the delivery of small interfering RNA (siRNA). Delivery remains a major challenge for translating siRNA to the clinic, and overcoming the delivery challenge requires effective siRNA delivery vehicles that meet the demands of the specific delivery strategy. Cross-linked polycationic nanoparticle formulations were synthesized using ARGET ATRP or UV-initiated polymerization. The one-step, one-pot, surfactant-stabilized monomer-in-water synthesis technique may provide a simpler and faster alternative to complicated, multistep techniques and an alternative to methods that rely on toxic organic solvents. The polymer nanoparticles were synthesized using the cationic monomer 2-(diethylamino)ethyl methacrylate, the hydrophobic monomer tert-butyl methacrylate to tune pH responsiveness, the hydrophilic monomer poly(ethylene glycol) methyl ether methacrylate to improve biocompatibility, and cross-linking agent tetraethylene glycol dimethacrylate to enhance colloidal stability. Four formulations were evaluated for their suitability as siRNA delivery vehicles in vitro with the human embryonic kidney cell line HEK293T or the murine macrophage cell line RAW264.7. The polycationic nanoparticles demonstrated efficient and rapid loading of the anionic siRNA following complexation. Confocal microscopy as well as flow cytometry analysis of cells treated with polycationic nanoparticles loaded with fluorescently labeled siRNA demonstrated that the polycationic nanoparticles promoted cellular uptake of fluorescently labeled siRNA. Knockdown experiments using polycationic nanoparticles to deliver siRNA demonstrated evidence of knockdown, thus demonstrating potential as an alternative route to creating polycationic nanoparticles.

A microscopic phenotypic assay for the quantification of intracellular mycobacteria adapted for high-throughput/high-content screening

Despite the availability of therapy and vaccine, tuberculosis (TB) remains one of the most deadly and widespread bacterial infections in the world. Since several decades, the sudden burst of multi- and extensively-drug resistant strains is a serious threat for the control of tuberculosis. Therefore, it is essential to identify new targets and pathways critical for the causative agent of the tuberculosis, Mycobacterium tuberculosis (Mtb) and to search for novel chemicals that could become TB drugs. One approach is to set up methods suitable for the genetic and chemical screens of large scale libraries enabling the search of a needle in a haystack. To this end, we developed a phenotypic assay relying on the detection of fluorescently labeled Mtb within fluorescently labeled host cells using automated confocal microscopy. This in vitro assay allows an image based quantification of the colonization process of Mtb into the host and was optimized for the 384-well microplate format, which is proper for screens of siRNA-, chemical compound- or Mtb mutant-libraries. The images are then processed for multiparametric analysis, which provides read out inferring on the pathogenesis of Mtb within host cells.

Wedelolactone inhibits LPS-induced pro-inflammation via NF-kappaB pathway in RAW 264.7 cells

BACKGROUND

Wedelolactone (WEL), a major coumestan ingredient in Wedelia chinensis, has been used to treat septic shock, hepatitis and venom poisoning in traditional Chinese medicines. The objective of the study was to elucidate the anti-inflammatory effects and mechanism of WEL with a cellular model of lipopolysaccharide (LPS)-induced RAW 264.7 cells.

RESULTS

To study the role of WEL in pro-inflammation, we measured key inflammation mediators and end products including nitric oxide (NO), prostaglandin E2 (PGE2), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2) and tumor necrosis factor-α (TNF-α) by using the Griess method, enzyme linked immunosorbent assay (ELISA) and Western blotting. Nuclear factor-kappaB (NF-κB) transcription activity was detected by luciferase reporter assay. The important pro-inflammatory transcription factors, NF-κB p65 and inhibitory kappaB alpha (IκB-α); and mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 MAPK (p38) were analyzed by Western blotting. Our study showed that WEL (0.1, 1, 10 μM) significantly inhibited the protein expression levels of iNOS and COX-2 in LPS-stimulated cells, as well as the downstream products, including NO, PGE2 and TNF-α. Moreover, WEL also inhibited LPS-induced NF-κB p65 activation via the degradation and phosphorylation of IκB-α and subsequent translocation of the NF-κB p65 subunit to the nucleus.

CONCLUSIONS

Our results revealed that WEL has a potential to be a novel anti-inflammatory agent targeting on the NF-κB signaling pathway.

A RANKL-PKCβ-TFEB signaling cascade is necessary for lysosomal biogenesis in osteoclasts

Bone resorption by osteoclasts requires a large number of lysosomes that release proteases in the resorption lacuna. Whether lysosomal biogenesis is a consequence of the action of transcriptional regulators of osteoclast differentiation or is under the control of a different and specific transcriptional pathway remains unknown. We show here, through cell-based assays and cell-specific gene deletion experiments in mice, that the osteoclast differentiation factor RANKL promotes lysosomal biogenesis once osteoclasts are differentiated through the selective activation of TFEB, a member of the MITF/TFE family of transcription factors. This occurs following PKCβ phosphorylation of TFEB on three serine residues located in its last 15 amino acids. This post-translational modification stabilizes and increases the activity of this transcription factor. Supporting these biochemical observations, mice lacking in osteoclasts--either TFEB or PKCβ--show decreased lysosomal gene expression and increased bone mass. Altogether, these results uncover a RANKL-dependent signaling pathway taking place in differentiated osteoclasts and culminating in the activation of TFEB to enhance lysosomal biogenesis-a necessary step for proper bone resorption.

The influence of natural pulmonary surfactant on the efficacy of siRNA-loaded dextran nanogels

AIM

Topical administration of siRNA nanocarriers is a promising approach in the treatment of pulmonary disorders. Pulmonary surfactant, covering the entire alveolar surface of mammalian lungs, will be one of the first interfaces that siRNA nanocarriers encounter upon inhalation therapy. Therefore, it is of outstanding importance to evaluate the impact of pulmonary surfactant on the performance of siRNA nanocarriers.

MATERIALS & METHODS

The effect of natural lung-derived surfactants on the siRNA delivery capacity of dextran nanogels (DEX-NGs) was evaluated in vitro using flow cytometry and confocal microscopy.

RESULTS

Although the interaction with pulmonary surfactant decreases the cellular internalization of siRNA-loaded DEX-NGs significantly, the gene silencing potential of siRNA-loaded DEX-NGs was maintained. On the other hand, cationic lipid-based siRNA nanocarriers (Lipofectamine™ RNAiMAX) were incompatible with pulmonary surfactants.

CONCLUSION

Our data suggest that pulmonary surfactant can enhance the intracellular siRNA delivery by DEX-NGs, thereby possibly providing new therapeutic opportunities.

Targeted polymersome delivery of siRNA induces cell death of breast cancer cells dependent upon Orai3 protein expression

Polymersomes, polymeric vesicles that self-assemble in aqueous solutions from block copolymers, have been avidly investigated in recent years as potential drug delivery agents. Past work has highlighted peptide-functionalized polymersomes as a highly promising targeted delivery system. However, few reports have investigated the ability of polymersomes to operate as gene delivery agents. In this study, we report on the encapsulation and delivery of siRNA inside of peptide-functionalized polymersomes composed of poly(1,2-butadiene)-b-poly(ethylene oxide). In particular, PR_b peptide-functionalized polymer vesicles are shown to be a promising system for siRNA delivery. PR_b is a fibronectin mimetic peptide targeting specifically the α(5)β(1) integrin. The Orai3 gene was targeted for siRNA knockdown, and PR_b-functionalized polymer vesicles encapsulating siRNA were found to specifically decrease cell viability of T47D breast cancer cells to a certain extent, while preserving viability of noncancerous MCF10A breast cells. siRNA delivery by PR_b-functionalized polymer vesicles was compared to that of a current commercial siRNA transfection agent, and produced less dramatic decreases in cancer cell viability, but compared favorably in regards to the relative toxicity of the delivery systems. Finally, delivery and vesicle release of a fluorescent encapsulate by PR_b-functionalized polymer vesicles was visualized by confocal microscopy, and colocalization with cellular endosomes and lysosomes was assessed by organelle staining. Polymersomes were observed to primarily release their encapsulate in the early endosomal intracellular compartments, and data may suggest some escape to the cytosol. These results represent a promising first generation model system for targeted delivery of siRNA.

Anti-inflammatory effects of dichloromethane fraction from Orostachys japonicus in RAW 264.7 cells: suppression of NF-κB activation and MAPK signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Orostachys japonicus A. Berger (O. japonicus) is known to reduce the risk of many diseases.

AIM OF THE STUDY

We investigated the anti-inflammatory effects of the dichloromethane (DCM) fraction from O. japonicus (OJD) in LPS-stimulated RAW 264.7 cells.

MATERIALS AND METHODS

NO was measured using the Griess method. Key pro-inflammatory cytokines and mediators including IL-1β, TLR4, iNOS, and COX-2; 2 important pro-inflammatory transcription factors, NF-κB p65 and IκBα; and MAPKs such as ERK1/2, JNK, and p38 were analyzed by Western blotting.

RESULTS

OJD significantly inhibited NO production, IL-1β, TLR4, iNOS, and COX-2 expression in LPS-stimulated cells. Additionally, it inhibited LPS-induced NF-κB p65 activation via inhibition of IκBα phosphorylation. Furthermore, phosphorylation of p38 and JNK was suppressed by OJD in a dose-dependent manner in the LPS-stimulated RAW 264.7 cells.

CONCLUSIONS

Our data suggest that OJD inhibits the inflammatory response via suppression of NF-κB activation and MAPK signaling.

Systems biology in immunology: a computational modeling perspective

Systems biology is an emerging discipline that combines high-content, multiplexed measurements with informatic and computational modeling methods to better understand biological function at various scales. Here we present a detailed review of the methods used to create computational models and to conduct simulations of immune function. We provide descriptions of the key data-gathering techniques employed to generate the quantitative and qualitative data required for such modeling and simulation and summarize the progress to date in applying these tools and techniques to questions of immunological interest, including infectious disease. We include comments on what insights modeling can provide that complement information obtained from the more familiar experimental discovery methods used by most investigators and the reasons why quantitative methods are needed to eventually produce a better understanding of immune system operation in health and disease.

Tales from an academic RNAi screening facility; FAQs

RNAi technology is now a well-established and widely employed research technique that has been adopted by many researchers for use in large-scale screening campaigns. Here, we offer our experience of genome-wide siRNA screening from the perspective of a facility providing screening as a service to a wide range of researchers with diverse interests and approaches. We have experienced the emotional rollercoaster of screening from the exuberant early promise of a screen, the messy reality of the data through to the recognition of screen data as a potential information goldmine. Here, we use some of the questions we most frequently encounter to highlight the initial concerns of many researchers embarking on a siRNA screen and conclude that an informed view of what can be reasonably expected from a screen is essential to the most effective implementation of the technology. Along the way, we suggest that for this area of research at least, either centralization of the resources or close and open collaboration between interested parties offers distinct advantages.

Dendritic polyglycerols with oligoamine shells show low toxicity and high siRNA transfection efficiency in vitro

RNA interference provides great opportunities for treating diseases from genetic disorders, infection, and cancer. The successful application of small interference RNA (siRNA) in cells with high transfection efficiency and low cytotoxicity is, however, a major challenge in gene-mediated therapy. Several pH-responsive core shell architectures have been designed that contain a nitrogen shell motif and a polyglycerol core, which has been prepared by a two-step protocol involving the activation of primary and secondary hydroxyl groups by phenyl chloroformate and amine substitution. Each polymer was analyzed by particle size and ζ potential measurements, whereas the respective polyplex formation was determined by ethidium bromide displacement assay, atomic force microscopy (AFM), and surface charge analysis. The in vitro gene silencing properties of the different polymers were evaluated by using a human epithelial carcinoma cell (HeLaS3) line with different proteins (Lamin, CDC2, MAPK2). Polyplexes yielded similar knockdown efficiencies as HiPerFect controls, with comparably low cytotoxicity. Therefore, these efficient and highly biocompatible dendritic polyamines are promising candidates for siRNA delivery in vivo.

Synthesis of linear polyamines with different amine spacings and their ability to form dsDNA/siRNA complexes suitable for transfection

In this paper we report on the synthesis of diversified linear polyamine architectures with different chain lengths and compositions and their interaction with phosphate groups of DNA/siRNA. The polyplex formation between model nucleotide (dsDNA) and these linear polyamines has been determined at different nitrogen to phosphorus (N/P) ratios using small-angle neutron scattering (SANS) and atomic force microscopy (AFM) techniques. AFM images showed that while linear poly(ethylene imine) (PEI)/DNA complex results in bigger spherical aggregates, poly(propylene imine)s forms torroid and cigar shaped structures upon complexation with DNA. The poly(butylene imine)s (LPBI)s form compact and soluble DNA complexes with a radii range of R(g) = 15-30 nm. Among the studied linear polyamines, the LPBIs did show the best transfection efficiency.

Alkyl sulfonyl derivatized PAMAM-G2 dendrimers as nonviral gene delivery vectors with improved transfection efficiencies

Amphiphilic dendrimer-based gene delivery vectors bearing peripheral alkyl sulfonyl hydrophobic tails were constructed using low-generation PAMAM-G2 as the core and functionalized by means of the aza-Michael type addition of its primary amino groups to vinylsulfone derivatives as an efficient tool for surface engineering. While the unmodified PAMAM-G2 was unable to efficiently transfect eukaryotic cells, functionalized PAMAM-G2 dendrimers were able to bind DNA at low N/P ratios, protect DNA from digestion with DNase I and showed high transfection efficiencies and low cytotoxicity. Dendrimers with a C18 alkyl chain produced transfection efficiencies up to 3.1 fold higher than LipofectAMINE™ 2000 in CHO-k1 cells. The dendriplexes based in functionalized PAMAM-G2 also showed the ability to retain their transfection properties in the presence of serum and the ability to transfect different eukaryotic cell lines such as Neuro-2A and RAW 264.7. Taking advantage of the vinylsulfone chemistry, fluorescent PAMAM-G2 derivatives of these vectors were prepared as molecular probes to determine cellular uptake and internalization through a clathrin-independent mechanism.