Alternative Delivery Mechanism Research Articles

Investigating the potential contribution of inter-track interactions within ultra-high dose-rate proton therapy

Objective. Laser-accelerated protons offer an alternative delivery mechanism for proton therapy. This technique delivers dose-rates of ≥109 Gy s−1, many orders of magnitude greater than used clinically. Such ultra-high dose-rates reduce delivery time to nanoseconds, equivalent to the lifetime of reactive chemical species within a biological medium. This leads to the possibility of inter-track interactions between successive protons within a pulse, potentially altering the yields of damaging radicals if they are in sufficient spatial proximity. This work investigates the temporal evolution of chemical species for a range of proton energies and doses to quantify the circumstances required for inter-track interactions, and determine any relevance within ultra-high dose-rate proton therapy. Approach. The TOPAS-nBio Monte Carlo toolkit was used to investigate possible inter-track interactions. Firstly, protons between 0.5 and 100 MeV were simulated to record the radial track dimensions throughout the chemical stage from 1 ps to 1 μs. Using the track areas, the geometric probability of track overlap was calculated for various exposures and timescales. A sample of irradiations were then simulated in detail to compare any change in chemical yields for independently and instantaneously delivered tracks, and validate the analytic model. Main results. Track overlap for a clinical 2 Gy dose was negligible for biologically relevant timepoints for all energies. Overlap probability increased with time after irradiation, proton energy and dose, with a minimum 23 Gy dose required before significant track overlap occurred. Simulating chemical interactions confirmed these results with no change in radical yields seen up to 8 Gy for independently and instantaneously delivered tracks. Significance. These observations suggest that the spatial separation between incident protons is too large for physico-chemical inter-track interactions, regardless of the delivery time, indicating such interactions would not play a role in any potential changes in biological response between laser-accelerated and conventional proton therapy.

Climate action and growing electricity demand: Meeting both challenges in the 21st century with space-based solar power delivered by space elevator

Global climate action is the grand challenge of the 21st century. Large reductions in greenhouse gas emissions are needed, with net-zero CO2 emissions by mid-century a requirement for many scenarios that restrain global warming below 1.5 °C by 2100. This will require massive deployment of renewables such as ground-based solar and wind, increased long-distance grid transmission capacity, and electrification of much of the global economy. Increased electrification, coupled with rising standards of living in developing countries, will drive ever-larger electricity demand to 2050 and beyond. And the intermittency, land-use, and transmission requirements of ground-based solar and wind present challenges to large-scale deployment to meet Net Zero targets. Space-based solar power (SSP) presents an enticing alternative, and with full reusability of upcoming heavy launch vehicles and modular SSP architectures, the economics of deployment are expected to become favorable in the coming decades. Efforts exist today to deploy demonstrators this decade, with initial production systems by 2050. However, deploying SSP at the scale required to address rising, global electricity demand will itself require orders-of-magnitude greater launch frequencies. If heavy launch frequency does not increase quickly enough, due to environmental concerns, launch site competition, or other bottlenecks, the dropping cost of launch will not be sufficient to enable SSP for global impact this century. A space elevator (SE) development program like that proposed by the International Space Elevator Consortium (ISEC) offers an alternative delivery mechanism for scaling SSP beyond 2050, hedging the risk of reliance on a single delivery system while reducing the time required for large-scale SSP deployment. To de-risk possible futures in which SSP is a major part of the global energy mix this century, a dual space access architecture is proposed, leveraging the strengths of heavy launch and SEs together. Such an architecture would secure the future for green energy on Earth, in 2050 and beyond.

Reinforcing effects of fentanyl and sufentanil aerosol puffs in rats.

Rapidly evolving e-cigarette technology developed for self-administering nicotine aerosol has the potential to be utilized to self-administer other aerosolized drugs of abuse. Rodent models which mirror characteristics of human e-cigarette use are necessary to explore the degree to which this may be a public health concern. Our goal was to develop a highly translational model of discrete nose-only aerosol puff drug delivery to explore the reinforcing effects of fentanyl and sufentanil aerosols in rats. Male and female Sprague-Dawley rats were trained to perform a multiple schedule FR1 lever-press, 4-s (second) nose hold operant during which the subject's orofacial areas were exposed to drug-free glycerol/propylene glycol aerosol produced by a commercial e-cigarette at a power setting of 18 watts. Each completed 4-s drug-free vehicle aerosol exposure resulted in a 3-s presentation of a 0.1-ml dipper of sweetened milk solution. After training, rats were then allowed to self-administer 4-s nose-only puffs of fentanyl (100-6000µg/ml) or sufentanil (30-500µg/ml) aerosol in the absence of paired milk dipper reinforcers. All 31 rats learned the lever-press/nose-poke multiple schedule for milk dippers alone and 25 accepted exposure to 4s of 18watts of drug-free vehicle aerosol when paired with milk dipper presentations. In the absence of paired milk dipper presentations, fentanyl aerosol puffs at concentrations of 1000 and 3000µg/ml as well as 100µg/ml puffs of sufentanil served as reinforcers compared to both air puffs and drug-free vehicle aerosol puffs. There were no significant differences between males and females in number of fentanyl or sufentanil puffs self-administered. Discrete nose-only puffs of two potent opioids under exposure conditions comparable to puff durations in human e-cigarette users serve as reinforcers in rats. This outcome suggests that under appropriate conditions e-cigarettes might be a potential alternative delivery mechanism for illicit opioids.

Dual anticancer drug-loaded self-assembled nanomaterials delivery system for the treatment of prostate cancer

This study explains the engineering of polylactide-polyethylene succinate glycol nanomaterials (NMs), to achieve superior anticancer effectiveness in prostate cancer therapy as a carriers of crizotinib (CZT) and marizomib (MAR). We have shown that the block polymers and hydrophobic drugs can be self-assembled to construct a highly stable nanocarrier with highly adaptable to support the use of cancer medicines. The Drug Release analysis revealed that the interference in the hydrophobic cores of micelles was a continuous release series. In both PC3pip and LNCAP prostate cancer cells, CZT@MAR NMs demonstrated noticeable cytotoxic effects in a dose-responsive method. In addition, morphology analysis and the AO-EB and nuclear staining assay showed a higher effectiveness in prostate cancer for nanomaterials. The polymeric nanomaterials displayed a prominent existence in the cytoplasmic cell regions, which shows a characteristic cell uptake by endocytosis. A significant apoptosis, compared to free CZT@MAR apoptosis, was found in the FITC-Annexin V/PI staining-based apoptosis analysis. In this juncture, the alternative drug delivery mechanism for the improvement of CZT@MAR chemotherapeutic effectiveness in prostate cancer chemotherapy modification PLA nanoparticles.

ONLINE EDUCATION: OPPORTUNITIES AND CHALLENGES

The paper explores the opportunities and challenges in providing online education. The revolution in telecom sector, growing demand of higher education, low gross enrollment ratio (GER) create the need to find alternative delivery mechanism to improve GER and provide skill enhancement to one of the largest population of young people (704 million, according to Euro Monitor 2012) in the world. National Mission on Education through ICT (NMICT) is a step in the right direction. But the scale of the services and courses is a cause of concern. The ministry of HRD has also initiated project Aakash in collaboration with IIT. Several state governments have promised laptops/tablets to the school pass outs to secure their victory in elections. The opportunity is realized by all concerned, but there is no dedicated effort to take the initiatives beyond the populist measures and convert the advantages of ICT into concrete results in terms of improvement in GER or skill enhancement. The regulatory framework is not yet ready to provide accreditation support to these initiatives. The paper concludes with recommendations to convert the opportunity into a success story for skill enhancement to ensure demographic dividend.

ALLOCATION OF RISK IN PUBLIC PRIVATE PARTNERSHIPS IN INFORMATION AND COMMUNICATIONS TECHNOLOGY

A public private partnership (PPP) is an agreement between a public and a private party to achieve a strategic objective. The PPP model is based on three principles: risk allocation and transfer, affordability, and value for money. Traditionally, PPPs have been leveraged for hard service development such as infrastructure development. The advancement of technology within the context of the Fourth Industrial Revolution (4IR) has created new opportunities and risks for PPPs as important mechanisms for the promotion of development. The 4IR has implications for government service delivery, which have brought about an increased demand for service delivery innovation and the development of information and communications technology (ICT). Although PPPs have traditionally focused on hard services, it is important to consider PPPs for soft service delivery. It is therefore necessary to rethink the role of the PPP model as an alternative service delivery mechanism. The aim of this article is to discuss risk allocation in ICT PPPs. The research approach is qualitative in nature. The research method is based on a desktop analysis of literature and secondary data utilising unobtrusive research techniques such as conceptual and documentary analyses. The article identified various risks and opportunities for PPPs for service delivery innovation. These partnerships are often faced with high levels of uncertainty in terms of funding, level of stakeholder commitment, and complex relationships. Other risks include vendor financing, market risk, intellectual property (IP) risk, data governance, and regulatory risk. The deployment of ICT can reinforce and expand PPPs beyond all previous limitations and boundaries. This research makes proposals for good practices for risk allocation in ICT PPPs.

Progress and Shortcomings of Cash Transfers and PDS Evidence from Delhi

Over a fourth of India’s population suffers acute poverty and deprivation. A critical part of concern must go to the process of extending welfare benefits to the poor, as public service delivery of these programs frequently suffers from technical flaws and administrative inefficiencies. Whereas India’s major programme for food security– the Public Distribution System – is largely criticised for erroneous inclusion and exclusion of beneficiaries, and diversion of food subsidies that accentuate the inability of people to access food, Cash Transfer as an alternative service delivery mechanism seeks to eliminate inefficiency and corruption by giving money directly to the poor. This paper compares the implementation of PDS and Cash Transfer in Delhi to look into the necessity of formulating public policy that defines appropriate and effective mechanisms to ensure food security. The objective of the study is to evaluate the possible outcome of CT as a dependable solution for ensuring food security while drawing attention to the implementation of the most popular in-kind transfer program in the country, that is, PDS, to attain food security. An empirical investigation using questionnaires-based survey covering 80 households and eight Focus Groups Discussions with beneficiaries, and interviews with concerned implementing agencies showed that both schemes formed an important basis in sustaining households’ basic needs, and had spill over effect on gender equation at the household level. Yet, exclusion and corruption continued to a larger extent in PDS compared to CT, and both lacked effective responsiveness and accountability in governance mechanisms.

Saving more in groups: Field experimental evidence from Chile

We test the impact of a peer group program on savings in a sample of microcredit clients. We conduct two randomized trials among these 2687 microcredit clients. The first finds that a Savings Group Treatment, which combines public goal setting, monitoring in the group and non-financial rewards, increases savings in a new savings account significantly. The number of deposits grows 3.7-fold and the average balance almost doubles. In contrast, a more classical measure, a substantially increased interest rate, has no effect for most participants and raises the savings balance only for the very top of the distribution. A second experiment, conducted a year later, tests an alternative delivery mechanism and shows that effects of similar size can be achieved through feedback text messages, without meetings, rewards, or peer pressure. Given that participants are borrowing at 90% APR, we discuss how and when saving more could be harmful or beneficial.

A Novel Mechanism for Protein Delivery by the Type 3 Secretion System for Extracellularly Secreted Proteins.

ABSTRACTThe type 3 secretion system (T3SS) is essential for bacterial virulence through delivering effector proteins directly into the host cytosol. Here, we identified an alternative delivery mechanism of virulence factors mediated by the T3SS, which consists of the association of extracellularly secreted proteins from bacteria with the T3SS to gain access to the host cytosol. Both EspC, a protein secreted as an enteropathogenic Escherichia coli (EPEC) autotransporter, and YopH, a protein detected on the surface of Yersinia, require a functional T3SS for host cell internalization; here we provide biophysical and molecular evidence to support the concept of the EspC translocation mechanism, which requires (i) an interaction between EspA and an EspC middle segment, (ii) an EspC translocation motif (21 residues that are shared with the YopH translocation motif), (iii) increases in the association and dissociation rates of EspC mediated by EspA interacting with EspD, and (iv) an interaction of EspC with the EspD/EspB translocon pore. Interestingly, this novel mechanism does not exclude the injection model (i.e., EspF) operating through the T3SS conduit; therefore, T3SS can be functioning as an internal conduit or as an external railway, which can be used to reach the translocator pore, and this mechanism appears to be conserved among different T3SS-dependent pathogens.

Association between Public Health Care Access and Financing of Health Infrastructure in India

Health financing is presumed to have an immense importance in designing the delivery mechanism in health care service. Financing in public health care institutions (comprising local, state and central governments, along with autonomous public sector bodies) is not observed to be adequate in India as compared to the global standard. As a result, the participation of private health care institutions in this health care domain is urgently called for to address the gap between demand for and supply of health care services. Health financing by non-governmental organizations (NGOs) as well as the government initiatives in the form of public–private partnership (PPP) signifies an alternative delivery mechanism in meeting the demand of such services. An attempt has been made in the study to examine the interstate variation of public health care access in India by considering a comprehensive index on public health care access. In addition, the study sheds some lights on the association between the outreach of health care access and the financing of the health care infrastructure in the context of different states of India. Empirical evidence suggested that the more health care financing by the government, the greater the outreach of the public health care services of a state. Thus, a significant contribution in health financing would facilitate the access of public health care by addressing the supply-side problems of the outreach of health care services in the Indian economy.

New Model for Understanding Mechanisms of Biological Signaling: Direct Transport via Cytonemes.

Biological signaling is a crucial natural process that governs the formation of all multicellular organisms. It relies on efficient and fast transfer of information between different cells and tissues. It has been presumed for a long time that these long-distance communications in most systems can take place only indirectly via the diffusion of signaling molecules, also known as morphogens, through the extracellular fluid; however, recent experiments indicate that there is also an alternative direct delivery mechanism. It utilizes dynamic tubular cellular extensions, called cytonemes, that directly connect cells, supporting the flux of morphogens to specific locations. We present a first quantitative analysis of the cytoneme-mediated mechanism of biological signaling. Dynamics of the formation of signaling molecule profiles, which are also known as morphogen gradients, is discussed. It is found that the direct-delivery mechanism is more robust with respect to fluctuations in comparison with the passive diffusion mechanism. In addition, we show that the direct transport of morphogens through cytonemes simultaneously delivers the information to all cells, which is also different from the diffusional indirect delivery; however, it requires energy dissipation and it might be less efficient at large distances due to intermolecular interactions of signaling molecules.

Push or Pull? A Website’s Strategic Choice of Content Delivery Mechanism

Really simple syndication (RSS) technology enables an alternative delivery mechanism for online content. Instead of waiting passively for users to pull online content out, websites can push it to potential users through RSS. This is expected to significantly affect user behavior, website profitability, and market equilibrium. This research uses an economic model to study the impact of RSS adoption and examine whether it increases a website’s profit and competitive advantage. The findings are intriguing: they demonstrate that RSS can either increase or decrease website profit. In a competitive context, RSS adoption can actually be a disadvantage; in some cases, it hurts the adopter but benefits the competitor. Moreover, under certain conditions, the first mover will be worse off when the competitor mimics its adoption decision, which discourages the earlier adoption and thus creates an obstacle to using RSS. Derivation of the adoption equilibria in sequential and simultaneous games shows that multiple market outcomes may result. Finally, regardless of whether or not a website operator adopts RSS, it will still benefit by increasing user awareness of RSS technology, but only up to a certain level. Once this critical awareness level has been reached, websites will not gain by continuing to promote RSS to users. As a whole, these results show how technology adoption will have an impact on firm performance and market outcome, and illustrate the complexity of technology adoption strategy in a competitive setting.

TATκ Fusion Protein of OCT-3/4 and KLF-4: Stable Mixed Population Cell Lines Capable of Delivering Fusion Proteins to Target Cells

A rapidly growing body of evidence has shown that enforced expression of a small panel of genes, including Oct-3/4, KLF4, Sox2 and c-Myc, can induce the reprogramming of previously differentiated cells, to generate induced Pluripotent Stem Cells (iPSCs). However, the generation of iPSCs by genetic modifications raises the risk of malignant transformation. Therefore, efficient in vitro reprogramming of differentiated cells, without irreversible genetic modification is highly desirable. The improved trans-activator of transcription kappa (TATκ), a synthetic TAT-HIV, confers the ability to deliver several proteins into target cells, thus, making it a potential alternative delivery mechanism for transcription factors or therapeutic agents. Using Green Fluorescence Protein (GFP) and Apoptin as model proteins, we have recently described a strategy to generate cell lines that secrete proteins carrying a modified HIV-TAT Protein Transduction Domain (PTD) for subsequent protein transduction mediated uptake by target cells. Using this strategy we have generated 293T cells secreting the pluripotent factors Oct-3/4 or KLF4 in fusion with TATκ. Oct-3/4 and KLF4 were detected in the culture medium of the transduced 293T cell and uptake of Oct-3/4 by haematopoietic cell lines JURKAT and FDCP-1 was confirmed by Western blot analysis. KLF4 was present in the culture medium of the producer 293T cell but we are still unable to demonstrate uptake by target cells. Based on results obtained, we hope that these stable mix population cell lines can play an important role in generation of iPSCs for therapeutic purposes.

Polymeric Nucleic Acid Vehicles Exploit Active Interorganelle Trafficking Mechanisms

Materials that self-assemble with nucleic acids into nanocomplexes (e.g. polyplexes) are widely used in many fundamental biological and biomedical experiments. However, understanding the intracellular transport mechanisms of these vehicles remains a major hurdle in their effective usage. Here, we investigate two polycation models, Glycofect (which slowly degrades via hydrolysis) and linear polyethyleneimine (PEI) (which does not rapidly hydrolyze), to determine the impact of polymeric structure on intracellular trafficking. Cells transfected using Glycofect underwent increasing transgene expression over the course of 40 h and remained benign over the course of 7 days. Transgene expression in cells transfected with PEI peaked at 16 h post-transfection and resulted in less than 10% survival after 7 days. While saccharide-containing Glycofect has a higher buffering capacity than PEI, polyplexes created with Glycofect demonstrate more sustained endosomal release, possibly suggesting an additional or alternative delivery mechanism to the classical "proton sponge mechanism". PEI appeared to promote release of DNA from acidic organelles more than Glycofect. Immunofluorescence images indicate that both Glycofect and linear PEI traffic oligodeoxynucleotides to the Golgi and endoplasmic reticulum, which may be a route towards nuclear delivery. However, Glycofect polyplexes demonstrated higher co-localization with the ER than PEI polyplexes, and co-localization experiments indicate the retrograde transport of polyplexes via COP I vesicles from the Golgi to the ER. We conclude that slow release and unique trafficking behaviors of Glycofect polyplexes may be due to the presence of saccharide units and the degradable nature of the polymer, allowing more efficacious and benign delivery.

Under-Savers Anonymous: Evidence on Self-Help Groups and Peer Pressure as a Savings Commitment Device

We test the effectiveness of self-help peer groups as a commitment device for precautionary savings, through two randomized field experiments among 2,687 microentrepreneurs in Chile. The first experiment finds that self-help peer groups are a powerful tool to increase savings (the number of deposits grows 3.5-fold and the average savings balance almost doubles). Conversely, a substantially higher interest rate has no effect on most participants. A second experiment tests an alternative delivery mechanism and shows that effects of a similar size can be achieved by holding people accountable through feedback text messages, without any meetings or peer pressure.

Relating nutrient and herbicide fate with landscape features and characteristics of 15 subwatersheds in the Choptank River watershed

Excess nutrients and agrochemicals from non-point sources contribute to water quality impairment in the Chesapeake Bay watershed and their loading rates are related to land use, agricultural practices, hydrology, and pollutant fate and transport processes. In this study, monthly baseflow stream samples from 15 agricultural subwatersheds of the Choptank River in Maryland USA (2005 to 2007) were characterized for nutrients, herbicides, and herbicide transformation products. High-resolution digital maps of land use and forested wetlands were derived from remote sensing imagery. Examination of landscape metrics and water quality data, partitioned according to hydrogeomorphic class, provided insight into the fate, delivery, and transport mechanisms associated with agricultural pollutants. Mean Nitrate-N concentrations (4.9 mg/L) were correlated positively with percent agriculture (R 2 = 0.56) and negatively with percent forest (R 2 = 0.60). Concentrations were greater ( p = 0.0001) in the well-drained upland (WDU) hydrogeomorphic region than in poorly drained upland (PDU), reflecting increased denitrification and reduced agricultural land use intensity in the PDU landscape due to the prevalence of hydric soils. Atrazine and metolachlor concentrations (mean 0.29 μg/L and 0.19 μg/L) were also greater ( p = 0.0001) in WDU subwatersheds than in PDU subwatersheds. Springtime herbicide concentrations exhibited a strong, positive correlation (R 2 = 0.90) with percent forest in the WDU subwatersheds but not in the PDU subwatersheds. In addition, forested riparian stream buffers in the WDU were more prevalent than in the PDU where forested patches are typically not located near streams, suggesting an alternative delivery mechanism whereby volatilized herbicides are captured by the riparian forest canopy and subsequently washed off during rainfall. Orthophosphate, CIAT (6-chloro- N-(1-methylethyl)-1,3,5-triazine-2,4-diamine), CEAT (6-chloro- N-ethyl-1,3,5-triazine-2,4-diamine), and MESA (2-[(2-ethyl-6-methylphenyl) (2-methoxy-1-methylethyl)amino]-2-oxoethanesulfonic acid) were also analyzed. These findings will assist efforts in targeting implementation of conservation practices to the most environmentally-critical areas within watersheds to achieve water quality improvements in a cost-effective manner.

An assessment of the present and future opportunities for combined heat and power with district heating (CHP-DH) in the United Kingdom

As global fuel reserves are depleted, alternative and more efficient forms of energy generation and delivery will be required. Combined heat and power with district heating (CHP-DH) provides an alternative energy production and delivery mechanism that is less resource intensive, more efficient and provides greater energy security than many popular alternatives. It will be shown that the economic viability of CHP-DH networks depends on several principles, namely (1) the optimisation of engineering and design principles; (2) organisational and regulatory frameworks; (3) financial and economic factors. It was found that in the long term DH is competitive with other energy supply and distribution technologies such as electricity and gas. However, in the short to medium term it is shown that economic risk, regulatory uncertainty and lock-in of existing technology are the most significant barriers to CHP-DH development. This research suggests that under the present regulatory and economic paradigm, the infrastructure required for DH networks remains financially prohibitive; the implementation of government policies are complicated and impose high transaction costs, while engineering solutions are frequently not implemented or economically optimised. If CHP-DH is going to play any part in meeting climate change targets then collaboration between public and private organisations will be required. It is clear from this analysis that strong local government involvement is therefore necessary for the co-ordination, leadership and infrastructural deployment of CHP-DH.

Relational partnerships: the importance of communication, trust and confidence and joint risk management in achieving project success

The advantages of relational partnerships as an alternative project delivery mechanism to the traditional methods have yet to be realized by the wider construction industry. In relational partnerships, all parties work together as a cohesive team to achieve an agreed outcome. However, an accurate estimation of the underlying factors associated with the relationships of these parties and assessment of their impacts on partnering success are difficult to achieve. By identifying three major factors, communication, trust and confidence and joint risk management, this research unfolded the relational links between these factors and analysed the impacts in the context of the relational partnering success. Based on a questionnaire survey and the structural equation modelling technique, results identified communication as the single most influencing factor impacting on relational partnering success. While trust and confidence were found to be mutually inclusive for effective communication, it was found to have direct influence on developing capability for joint risk management within the partnering organizations. This finding diverges from the widely accepted view across the Australian construction industry that partnering is built on trust and confidence only and any risks associated in projects are best dealt with by means of joint responsibility without any problems.

Tim‐2 is the receptor for H‐ferritin on oligodendrocytes

Oligodendrocytes stain more strongly for iron than any other cell in the CNS, and they require iron for the production of myelin. For most cell types transferrin is the major iron delivery protein, yet neither transferrin receptor protein nor mRNA are detectable in mature oligodendrocytes. Thus an alternative iron delivery mechanism must exist. Given the significant long term consequences of developmental iron deficiency and the iron requirements for normal myelination, identification of the iron delivery mechanism for oligodendrocytes is important. Previously we have reported that oligodendrocytes bind H-ferritin and that H-ferritin binds to white matter tracts in vivo. Recently, T cell immunoglobulin and mucin domain-containing protein-2 (Tim-2) was shown to bind and internalize H-ferritin. In the present study we show that Tim-2 is expressed on oligodendrocytes both in vivo and in vitro. Further, the onset of saturable H-ferritin binding in CG4 oligodendrocyte cell line is accompanied by Tim-2 expression. Application of a blocking antibody to the extracellular domain of Tim-2 significantly reduces H-ferritin binding to the differentiated CG4 cells and primary oligodendrocytes. Tim-2 expression on CG4 cells is responsive to iron; decreasing with iron loading and increasing with iron chelation. Taken together, these data provide compelling evidence that Tim-2 is the H-ferritin receptor on oligodendrocytes suggesting it is the primary mechanism for iron acquisition by these cells.

Arginine-rich cell-penetrating peptides facilitate delivery of antisense oligomers into murine leukocytes and alter pre-mRNA splicing

Phosphorodiamidate morpholino oligomers (PMO) are synthetic antisense molecules that interfere with translation, pre-mRNA splicing and RNA synthesis. Like other gene-silencing technologies, PMO are poorly taken up by primary leukocytes without the use of physical or chemical delivery techniques. We sought an alternative delivery mechanism of PMO into immune cells that eliminates the need for such manipulations. Here we demonstrate the first use of arginine-rich cell-penetrating peptides (CPPs) to deliver PMO (P-PMO) directly into primary murine leukocytes for inhibition of gene expression and promotion of altered pre-mRNA splicing. We compared the P-PMO delivery efficacy of four arginine-rich CPPs including HIV Tat and penetratin, and one histidine rich CPP, and found that the (RXR) 4 peptide was the most efficacious for PMO delivery and targeted antisense effect. The delivery and antisense effects of P-PMO are time- and dose-dependent and influenced by the activation and maturation states of T cells and dendritic cells, respectively. Targeted expression of several genes using P-PMO is shown including surface signaling proteins (CD45 and OX-40), a cytokine (interleukin-2), and a nuclear transcription factor (Foxp3). Considering the abundance of naturally occurring alternatively spliced gene products involved in immune regulation, P-PMO offer an effective method for modulating gene activity for immunological research and applications beyond traditional antisense approaches.