Nucleic Acid Binding Polymers Research Articles

Do Nucleic Acid–Binding Polymers (Nabps) May Be Reduce Proinflammatory Nucleic Acids Among Trauma-Associated Hemorrhagic Shock?

Do Nucleic Acid–Binding Polymers (Nabps) May Be Reduce Proinflammatory Nucleic Acids Among Trauma-Associated Hemorrhagic Shock?

Comparative Analysis of Nucleic Acid-Binding Polymers as Potential Anti-Inflammatory Nanocarriers.

Conventionally, nanocarriers are used to regulate the controlled release of therapeutic payloads. Increasingly, they can also be designed to have an intrinsic therapeutic effect. For example, a positively charged nanocarrier can bind damage-associated molecular patterns, inhibiting toll-like receptor (TLR) pathway activation and thus modulating inflammation. These nucleic acid-binding nanomaterials (NABNs), which scavenge pro-inflammatory stimuli, exist in diverse forms, ranging from soluble polymers to nanoparticles and 2D nanosheets. Unlike conventional drugs that primarily address inflammation symptoms, these NABPs target the upstream inflammation initiation pathway by removing the agonists responsible for inflammation. Many NABNs have demonstrated effectiveness in murine models of inflammatory diseases. However, these scavengers have not been systematically studied and compared within a single setting. Herein, we screen a subset of the most potent NABNs to define their relative efficiency in scavenging cell-free nucleic acids and inhibiting various TLR pathways. This study helps interpret existing in vivo results and provides insights into the future design of anti-inflammatory nanocarriers.

Mixed-surface polyamidoamine polymer variants retain nucleic acid-scavenger ability with reduced toxicity.

Nucleic acid-binding polymers can have anti-inflammatory properties and beneficial effects in animal models of infection, trauma, cancer, and autoimmunity. PAMAM G3, a polyamidoamine dendrimer, is fully cationic bearing 32 protonable surface amines. However, while PAMAM G3 treatment leads to improved outcomes for mice infected with influenza, at risk of cancer metastasis, or genetically prone to lupus, its administration can lead to serosal inflammation and elevation of biomarkers of liver and kidney damage. Variants with reduced density of cationic charge through the interspersal of hydroxyl groups were evaluated as potentially better-tolerated alternatives. Notably, the variant PAMAM G3 50:50, similar in size as PAMAM G3 but with half the charge, was not toxic in cell culture, less associated with weight loss or serosal inflammation after parenteral administration, and remained effective in reducing glomerulonephritis in lupus-prone mice. Identification of such modified scavengers should facilitate their development as safe and effective anti-inflammatory agents.

β-Cyclodextrin-containing polymer treatment of cutaneous lupus and influenza improves outcomes

Nucleic acid (NA)-containing damage- and pathogen-associated molecular patterns (DAMPs and PAMPs, respectively) are implicated in numerous pathological conditions from infectious diseases to autoimmune disorders. Nucleic acid-binding polymers, including polyamidoamine (PAMAM) dendrimers, have demonstrated anti-inflammatory properties when administered to neutralize DAMPs/PAMPs. The PAMAM G3 variant has been shown to have beneficial effects in a cutaneous lupus erythematosus (CLE) murine model and improve survival of mice challenged with influenza. Unfortunately, the narrow therapeutic window of cationic PAMAM dendrimers makes their clinical development challenging. An alternative nucleic acid-binding polymer that has been evaluated in humans is a linear β-cyclodextrin-containing polymer (CDP). CDP's characteristics prompted us to evaluate its anti-inflammatory potential in CLE autoimmune and influenza infectious disease mouse models. We report that CDP effectively inhibits NA-containing DAMP-mediated activation of Toll-like receptors (TLRs) in cell culture, improves healing in lupus mice, and does not immunocompromise treated animals upon influenza infection but improves survival even when administered 3days after infection. Finally, as anticipated, we observe limited toxicity in animals treated with CDP compared with PAMAM G3. Thus, CDP is a new anti-inflammatory agent that may be readily translated to the clinic to combat diseases associated with pathological NA-containing DAMPs/PAMPs.

Targeting multiple mediators of sepsis using multifunctional tannic acid-Zn2+-gentamicin nanoparticles

Targeting multiple mediators of sepsis using multifunctional tannic acid-Zn2+-gentamicin nanoparticles

Abstract P3-01-03: Modulating inflammation with nucleic acid scavengers to prevent breast cancer metastasis

Abstract Rationale: Chronic inflammation is a hallmark of cancer. Inflammation, whether it is an underlying baseline condition or induced/exacerbated due to treatment, is a major hurdle that ultimately impacts the efficacy of standard of care therapy. However, no strategy exists to effectively control endogenous or therapy-induced inflammation in women with breast cancer. Moreover, there is limited information on how endogenous or therapy-induced inflammation modulates immune cells in women with breast cancer. Nucleic acid-containing pro-inflammatory complexes, termed Nucleic Acid-containing Damage Associated Molecular Patterns (NA-DAMPs), are released from dead or dying cancer cells or activated immune cells. NA-DAMPs activate nucleic acid sensing toll-like receptors (TLR) and other pattern recognition receptors (PRR). NA-DAMPs promote tumor progression and metastasis by inducing pro-tumorigenic signaling in cancer cells. Excessive and persistent NA-DAMP-mediated PRR signaling in immune cells is associated with immune dysfunction. Nucleic acid binding polymers have been used as vehicles for DNA/RNA delivery. We have discovered that a subset of nucleic acid binding polymers, termed nucleic acid scavengers (NAS), act as anti-inflammatory agents by capturing cancer-promoting pro-inflammatory NA-DAMPs. Therefore, we investigated if a NAS could limit cancer progression and metastasis by capturing and mitigating the effects of NA-DAMPs in immunocompetent murine models of breast cancer. Methods: We tested the use of the NAS PAMAM-G3 in the 1] orthotopic surgical resection 4T1 breast cancer model; 2] intravenous experimental metastasis 4T1 breast cancer model; 3] MMTV-PyMT spontaneous breast cancer model. We also measured changes in inflammation/inflammatory cell profile in tumor and in blood. Next, we investigated the relationship between therapy, NA-DAMPs and immune cell profile in blood from women with breast cancer. We also examined if NA-DAMPs in patient serum induces tumor invasion and if the NAS PAMAM-G3 prevents tumor invasion using an in vitro assay. Results: We have determined that the NAS PAMAM-G3 controls lung metastasis in immunocompetent murine models of breast cancer and our data indicate that: 1] chronic inflammation and inflammatory cells in the tumor and periphery promote cancer invasion and metastasis; 2] modulating inflammation by removing excessive NA-DAMPs using the NAS PAMAM-G3 limits cancer metastasis; 3] scavenging inflammation-associated NA-DAMPs significantly alters immune cell and cytokine/chemokine profile in the tumor and periphery, promotes T cell infiltration in the tumor and induces antitumor CD8+ T cell responses. In experiments conducted using blood collected longitudinally from women undergoing standard of care therapy, we observed that: 1] NA-DAMPs and inflammatory monocytes are elevated in women undergoing standard of care therapy; 2] Post-chemotherapy breast cancer patient serum increases invasion/migration of human breast cancer cells in vitro; 3] PAMAM-G3 abrogates increase in invasion/migration of human breast cancer cells in vitro in response to post-chemotherapy breast cancer patient serum. Conclusions: These results highlight the potential utility of NAS to treat cancer associated inflammation and thereby inhibit cancer metastasis by 1) limiting extracellular NA-DAMP-induced persistent activation of pro-inflammatory signaling, and 2) promoting full engagement of both the innate and adaptive immune systems. These principles will aid in the development of a novel anti-metastatic therapy for women with breast cancer. This work is supported by Department of Defense Breast Cancer Research Program Awards W81XWH-16-1-0512 (Nair) and W81XWH-16-1-0513 (Sullenger). Citation Format: Smita Nair, Eda Holl, Karenia Landa, Victoria Frazier, Elias Eteshola, David Boczkowski, Rachel Rempel, Shelley Hwang, Bruce Sullenger. Modulating inflammation with nucleic acid scavengers to prevent breast cancer metastasis [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-01-03.

Targeting DAMP-induced inflammation to prevent breast cancer metastasis and improve anti-tumor immunity

Abstract Biomarkers associated with systemic inflammation correlate with poor prognosis in cancer patients. Circulating cell-free DNA (cfDNA) is released passively and actively by both tumor cells and host cells and cfDNA levels in blood correlate with tumor burden in many tumor types. Notably, studies in breast cancer have shown that inhibition of cfDNA has a significant effect in reducing invasion and migration in vitro and metastatic disease in vivo. We have previously demonstrated that nucleic acid binding polymers (NABPs) bind and inhibit the proinflammatory effects of cfDNA in a murine model of pancreatic cancer. We observed that levels of cfDNA in blood increase with tumor burden in an orthotopic immunocompetent murine model of breast cancer. Moreover, treatment of mice with the NABP, PAMAM-G3, following surgical removal of primary tumor results in decreased lung metastasis. This decrease in lung metastasis is associated with reduction in the levels of cfDNA in blood. In addition, treatment of mice with NABPs in an intravenous experimental metastasis breast cancer model results in reduced seeding of tumor cells in lungs and lung metastasis. Analysis of immune infiltrates in lungs of PAMAM-G3- and control-treated mice demonstrates NABP-mediated transition of immune cell composition in lungs from innate to adaptive immune cells. Collectively, these data suggest that NABPs can be used to target cfDNA and inhibit DAMPs associated pathological inflammation. The use of NABPs is an innovative approach to treat cancer progression and metastasis, particularly in a clinical setting following standard of care surgical tumor resection. This work is funded by the Department of Defense Breast Cancer Research Program award (PI, Smita Nair).

Molecular Dynamics Simulations on Nucleic Acid Binding Polymers Designed To Arrest Thrombosis.

Cancer-associated thrombosis is managed by the administration of anticoagulants and antithrombotic agents that have a high risk of inducing hemorrhagic complications. To develop safer strategies for antithrombotic therapy, in vivo activators of the intrinsic pathway, namely, cell-free nucleic acids (DNA and RNA) have been targeted with cationic, polyamine-based polymers. The cytotoxicity of the highly cationic polymers is a major drawback for their practical use, and biocompatible alternatives are in high demand. In this study, we carried out all-atom molecular dynamics simulations to systematically examine the DNA binding of polyamine-poly(ethylene glycol) (PEG) diblock polymers designed from biocompatible building blocks to inhibit the procoagulant activity of DNA. The differences in cationic charge, PEG chain length, and initial conformations of the polymers resulted in marked differences in their binding to DNA. We found that having an exposed cationic polyamine group is essential to polymer-DNA binding and a certain level of electrostatic interactions is necessary to maintain the bound state. Intrachain associations between the polyamine groups and PEG chains in some cases have led to a collapsed state of the polymer that precludes binding to DNA. This self-association is mainly due to a strong hydrogen bond between polymer polyamine and PEG groups and partly due to a partially charged semibranched polyamine group architecture. As polymer "masking" of DNA is thought to arrest DNA's prothrombotic activity, our findings highlight the desired structural features of the polymers for stronger DNA binding and provide insights into the design of novel antithrombotic agents.

Targeting inflammation to prevent breast cancer metastasis

Abstract Biomarkers associated with systemic inflammation correlate with poor prognosis in cancer patients. Circulating cell-free DNA (cfDNA) is released passively and actively by both tumor cells and host cells and cfDNA levels in blood correlate with tumor burden in many tumor types. Notably, studies in breast cancer have shown that inhibition of cfDNA has a significant effect in reducing invasion and migration in vitro. We have previously demonstrated the ability of nucleic acid binding polymers (NABPs) to bind and inhibit the pro-inflammatory effects of cfDNA and RNA in models of systemic lupus erythematosus and influenza. Herein, we demonstrate that in tumor bearing mice, levels of cfDNA increase with tumor burden and decline post NABP in vivo administration. Using an orthotopic breast cancer murine model we demonstrate that NABP treatment, following surgical resection, results in reduced or completely absent lung metastasis. In addition, intravenous delivery of breast cancer cells in the presence of NABPs also results in decreased tumor cell lung seeding and lung metastasis. Taken together, our data suggest that NABPs can be used to target cfDNA and inhibit such DAMPs from activating pathological inflammation, an innovative approach to treat cancer progression and metastasis. In particular, NABPs may be useful in the clinical setting following standard of care surgical tumor resection.

Polymer-Mediated Inhibition of Pro-invasive Nucleic Acid DAMPs and Microvesicles Limits Pancreatic Cancer Metastasis.

Nucleic acid binding polymers (NABPs) have been extensively used as vehicles for DNA and RNA delivery. More recently, we discovered that a subset of these NABPs can also serve as anti-inflammatoryagents by capturing pro-inflammatory extracellular nucleic acids and associated protein complexes that promote activation of toll-like receptors (TLRs) in diseases such as lupuserythematosus. Nucleic-acid-mediated TLR signaling also facilitates tumor progression and metastasis in several cancers, including pancreatic cancer (PC). In addition, extracellular DNA and RNA circulate on or within lipid microvesicles, such as microparticles or exosomes, which also promote metastasis by inducing pro-tumorigenic signaling in cancer cells and pre-conditioning secondary sites for metastatic establishment. Here, we explore the use of an NABP, the 3rd generation polyamidoamine dendrimer (PAMAM-G3), as an anti-metastatic agent. We show that PAMAM-G3 not only inhibits nucleic-acid-mediated activation of TLRs and invasion of PC tumor cells invitro, but can also directly bind extracellular microvesicles to neutralize their pro-invasive effects as well. Moreover, we demonstrate that PAMAM-G3 dramatically reduces liver metastases in a syngeneic murine model of PC. Our findings identify a promising therapeutic application of NABPs for combating metastatic disease in PC and potentially other malignancies.

Immunothrombotic Activity of Damage-Associated Molecular Patterns and Extracellular Vesicles in Secondary Organ Failure Induced by Trauma and Sterile Insults.

Despite significant improvements in injury prevention and emergency response, injury-related death and morbidity continues to increase in the US and worldwide. Patients with trauma, invasive operations, anti-cancer treatment, and organ transplantation produce a host of danger signals and high levels of pro-inflammatory and pro-thrombotic mediators, such as damage-associated molecular patterns (DAMPs) and extracellular vesicles (EVs). DAMPs (e.g., nucleic acids, histone, high-mobility group box 1 protein, and S100) are molecules released from injured, stressed, or activated cells that act as endogenous ligands of innate immune receptors, whereas EVs (e.g., microparticle and exosome) are membranous vesicles budding off from plasma membranes and act as messengers between cells. DAMPs and EVs can stimulate multiple innate immune signaling pathways and coagulation cascades, and uncontrolled DAMP and EV production causes systemic inflammatory and thrombotic complications and secondary organ failure (SOF). Thus, DAMPs and EVs represent potential therapeutic targets and diagnostic biomarkers for SOF. High plasma levels of DAMPs and EVs have been positively correlated with mortality and morbidity of patients or animals with trauma or surgical insults. Blocking or neutralizing DAMPs using antibodies or small molecules has been demonstrated to ameliorate sepsis and SOF in animal models. Furthermore, a membrane immobilized with nucleic acid-binding polymers captured and removed multiple DAMPs and EVs from extracellular fluids, thereby preventing the onset of DAMP- and EV-induced inflammatory and thrombotic complications in vitro and in vivo. In this review, we will summarize the current state of knowledge of DAMPs, EVs, and SOF and discuss potential therapeutics and preventive intervention for organ failure secondary to trauma, surgery, anti-cancer therapy, and allogeneic transplantation.

Extracellular nucleic acids in immunity and cardiovascular responses: between alert and disease.

Severe inflammatory complications are a potential consequence in patients with predetermined conditions of infections, pulmonary diseases, or cardiovascular disorders. Notably, the amplitude of the inflammatory response towards these complications can dictate the disease progression and outcome. During the recent years, evidence from basic research as well as from clinical studies has identified self-extracellular nucleic acids as important players in the crosstalk between immunity and cardiovascular diseases. These stress- or injury-induced endogenous polymeric macromolecules not only serve as "alarmins" or "Danger-associated molecular patterns" (DAMPs), but their functional repertoire goes far beyond such activities in innate immunity. In fact, (patho-) physiological functions of self-extracellular DNA and RNA are associated and in many cases causally related to arterial and venous thrombosis, atherosclerosis, ischemia-reperfusion injury or tumour progression. Yet, the underlying molecular mechanisms are far from being completely understood. Interestingly enough, however, novel antagonistic approaches in vitro and in vivo, particularly using natural endonucleases or synthetic nucleic acid binding polymers, appear to be promising and safe therapeutic options for future studies. The aim of this review article is to provide an overview of the current state of (patho-) physiological functions of self-extracellular nucleic acids with special emphasis on their role as beneficial / alerting or adverse / damaging factors in connection with immune responses, inflammation, thrombosis, and cardiovascular diseases.

Nucleic acid scavenging microfiber mesh inhibits trauma-induced inflammation and thrombosis.

Trauma patients produce a host of danger signals and high levels of damage-associated molecular patterns (DAMPs) after cellular injury and tissue damage. These DAMPs are directly and indirectly involved in the pathogenesis of various inflammatory and thrombotic complications in patients with severe injuries. No effective therapeutic agents for the removal of DAMPs from blood or tissue fluid have been developed. Herein, we demonstrated that nucleic acid binding polymers, e.g., polyethylenimine (PEI) and polyamidoamine dendrimers, immobilized onto electrospun microfiber mesh can effectively capture various DAMPs, such as extracellular DNAs and high mobility group box 1 (HMGB1). Furthermore, treatment with PEI-immobilized microfiber mesh abrogated the ability of DAMPs, released from dead and dying cells in culture or found in patients following traumatic injury, to activate innate immune responses and coagulation invitro and invivo. Nucleic acid scavenging microfiber meshes represent an effective strategy to combat inflammation and thrombosis in trauma.

Scavenging nucleic acid debris to combat autoimmunity and infectious disease

Nucleic acid-containing debris released from dead and dying cells can be recognized as damage-associated molecular patterns (DAMPs) or pattern-associated molecular patterns (PAMPs) by the innate immune system. Inappropriate activation of the innate immune response can engender pathological inflammation and autoimmune disease. To combat such diseases, major efforts have been made to therapeutically target the pattern recognition receptors (PRRs) such as the Toll-like receptors (TLRs) that recognize such DAMPs and PAMPs, or the downstream effector molecules they engender, to limit inflammation. Unfortunately, such strategies can limit the ability of the immune system to combat infection. Previously, we demonstrated that nucleic acid-binding polymers can act as molecular scavengers and limit the ability of artificial nucleic acid ligands to activate PRRs. Herein, we demonstrate that nucleic acid scavengers (NASs) can limit pathological inflammation and nucleic acid-associated autoimmunity in lupus-prone mice. Moreover, we observe that such NASs do not limit an animal's ability to combat viral infection, but rather their administration improves survival when animals are challenged with lethal doses of influenza. These results indicate that molecules that scavenge extracellular nucleic acid debris represent potentially safer agents to control pathological inflammation associated with a wide range of autoimmune and infectious diseases.

Abstract 4554: Toll-like receptor expression and ligation promotes in vitro invasion in pancreatic cancer

Abstract Introduction: Pancreatic cancer (PC) has the worst prognosis of all the major cancers. The role of inflammation in tumor progression and metastasis, particularly in PC, is widely accepted. Our lab has recently shown that levels of circulating cell-free DNA (cfDNA) and associated proteins (histones, HMGB-1, etc.) are elevated in PC patients at baseline and increase in response to standard therapies. It is also known that components of the innate immune system respond to cfDNA and associated proteins. Specifically, the toll-like receptors (TLRs) have been shown to be activated by cfDNA and associated proteins. These TLRs, specifically TLR-4 and TLR-9, have been shown to promote tumor progression and metastasis in other cancers such as breast, colorectal, and skin cancers. We wanted to investigate the role of TLRs in PC by characterizing receptor expression and downstream function. We also attempted to inhibit the downstream effects of TLR signaling using nucleic acid binding polymers (NABPs) that our lab has previously utilized in other disease models such as systemic lupus erythematosus. Methods: Three human (MiaPaCa-2, BxPC-3, PANC-1) and one murine (KPC-4580P) PC cell line were characterized for TLR-4 and TLR-9 expression by western blot. Briefly, cells were plated and lysed using RIPA buffer. Total protein concentration was quantified using bicinchoninic acid (BCA) assay and normalized prior to running the cell lysates on SDS-PAGE. The protein bands were then transferred to immunoblotting membrane and probed with specific primary antibodies, followed by fluorescent secondary antibodies. Blots were exposed and quantified via LI-COR. Downstream function of TLR expression was tested using Transwell-matrigel invasion assays wherein cells were plated in the Transwell system in the presence of TLR-4 and TLR-9 specific agonists (LPS and CpG or mtDNA, respectively). These cells were also treated with NABPs to inhibit TLR activation. Results: All PC cell lines expressed TLR-4 and TLR-9. The invasion assays indicated that in the presence of TLR-4 and TLR-9 specific agonists, PC cells exhibited increased invasion. Moreover, PC cells that invaded in response to TLR-9 agonists were inhibited in the presence of NABPs. Our lab has also prepared conditioned media (CM) from cells treated with clinically relevant doses of radiation. Our PC cell lines displayed increased invasiveness in response to CM and decreased with NABP treatment. Conclusion: We have previously shown that there are elevated levels of cfDNA and associated proteins in PC patient serum and have now shown that these factors can have direct effects on PC cells via TLRs that are expressed by the cancer cells. Treating cells with NABPs in the presence of TLR agonists can abrogate TLR mediated invasion in vitro. Our goal is to further characterize the effects of TLR signaling on cancer cells including RNA transcription and protein translation profiling. Citation Format: Ibtehaj A. Naqvi, Jessica McDade, Jaewoo Lee, Rebekah White. Toll-like receptor expression and ligation promotes in vitro invasion in pancreatic cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4554.

Immobilization of nucleic acid binding polymers as anti-inflammatory agent in autoimmunity

Immobilization of nucleic acid binding polymers as anti-inflammatory agent in autoimmunity

11. Nucleic-Acid Binding Polymers as Anti-Inflammatory Agents

11. Nucleic-Acid Binding Polymers as Anti-Inflammatory Agents

New players in haemostasis and thrombosis

The blood coagulation cascade is essential for haemostasis, but excessive activation can cause thrombosis. Importantly, recent studies have identified factors that contribute to thrombosis but not haemostasis. These include factor XII (FXII), tissue factor-positive microparticles (MPs) and neutrophil extracellular traps (NETs). Studies have shown that FXII plays a role in thrombosis but not haemostasis. FXII is activated in vivo by a variety of negatively-charged polyphosphates, which include extracellular RNA, DNA and inorganic polyphosphate (PolyP) that are released during cell damage and infection. These findings have led to the development of nucleic acid-binding polymers as a new class of anticoagulant drug. Other studies have analysed the role of MPs in experimental thrombosis. MPs are small membrane vesicles released from activated or apoptotic cells. We and others have found that tissue factor-positive MPs enhance thrombosis in mouse models and are elevated in the plasma of pancreatic cancer patients. Finally, NETs have been shown to contribute to experimental venous thrombosis in mouse models and are present in human thrombi. NETs are composed of chromatin fibers that are released from neutrophils undergoing cell death. NETs can capture platelets and increase fibrin deposition. The recent advances in our understanding of the factors contributing to thrombosis in animal models provide new opportunities for the development of safer anticoagulant drugs.

O006 Role of nucleic acid-binding polymers in TLR activation and autoimmune disease development

Introduction Toll-like receptors (TLRs) play a critical role in innate and adaptive immune responses by responding to pathogenic nucleic acids. Moreover, they have recently been shown to play a role in the pathogenesis of autoimmune disorders such as systemic lupus erythematosus (SLE) due to their ability to recognize self-antigens. There has been growing evidence suggesting that blocking of nucleic acid-sending TLRs such as TLR7 and 9 results in ameliorated disease. Although effective in blocking autoimmune disease progression, TLR inhibitors are not ideal given that they interfere with normal responses to pathogens. Our goal is to create compounds that bind nucleic acids prior to their entry into the cell and engagement of TLRs. Here we determined the role of nucleic acid-binding cationic polymers in neutralizing the proinflammatory effects of nucleic acids on a variety of immune cells implicated in autoimmune disease development. Methods B cells and dendritic cells (DCs) of wild type and lupus prone mice were exposed to TLR7 and 9 synthetic agonists. Supernatants were subsequently assessed for nucleic acid-driven proinflammatory cytokine release, plasma cell differentiation and antibody production. Cells were also assessed for their ability to respond to encapsulated viral particles in the presence of nucleic-acid binding cationic polymers. Results Nucleic acid-binding polymers inhibit TLR activation and subsequent cytokine production by both dendritic cells (DCs) and B cells of wild type and lupus prone mice. They also block nucleic acid-driven plasma cell differentiation and antibody production. Additionally, they modulate co-stimulatory cell surface marker expression (CD80, CD86) in stimulated DCs and B cells. Stimulation of immune cells by encapsulated viral particles is unaffected in the presence of polymers. Conclusion These findings provide a new avenue in drug development as nucleic acid-binding agents can potentially be utilized to block overt autoimmune disorders while allowing normal immune responses to occur.

Nucleic acid scavengers inhibit thrombosis without increasing bleeding

Development of effective, yet safe, antithrombotic agents has been challenging because such agents increase the propensity of patients to bleed. Recently, naturally occurring polyphosphates such as extracellular DNA, RNA, and inorganic polyphosphates have been shown to activate blood coagulation. In this report, we evaluate the anticoagulant and antithrombotic activity of nucleic acid-binding polymers in vitro and in vivo. Such polymers bind to DNA, RNA, and inorganic polyphosphate molecules with high affinity and inhibit RNA- and polyphosphate-induced clotting and the activation of the intrinsic pathway of coagulation in vitro. Moreover, [NH(2)(CH(2))(2)NH(2)](G = 3);dendri PAMAM(NH(2))(32) (PAMAM G-3) prevents thrombosis following carotid artery injury and pulmonary thromboembolism in mice without significantly increasing blood loss from surgically challenged animals. These studies indicate that nucleic acid-binding polymers are able to scavenge effectively prothrombotic nucleic acids and other polyphosphates in vivo and represent a new and potentially safer class of antithrombotic agents.