Targeted delivery of siRNA to macrophages for anti-inflammatory treatment

Frontiers of Neurodegenerative Disease Treatment: Targeting Immune Cells in Brain Border Regions

Neurodegenerative diseases (NDs) demonstrate a complex interaction with the immune system, challenging the traditional view of the brain as an "immune-privileged" organ. Microglia were once considered the sole guardians of the brain's immune response. However, recent research has revealed the critical role of peripheral immune cells located in key brain regions like the meninges, choroid plexus, and perivascular spaces. These previously overlooked cells are now recognized as contributors to the development and progression of NDs. This newfound understanding opens doors for pioneering therapeutic strategies. By targeting these peripheral immune cells, we may be able to modulate the brain's immune environment, offering an alternative approach to treat NDs and circumvent the challenges posed by the blood-brain barrier. This comprehensive review will scrutinize the latest findings on the complex interactions between these peripheral immune cells and NDs. It will also critically assess the prospects of targeting these cells as a ground-breaking therapeutic avenue for these debilitating disorders.

Targeted delivery of extracellular vesicles: the mechanisms, techniques and therapeutic applications

Extracellular vesicles (EVs) are cell-derived vesicles with a phospholipid bilayer measuring 50-150 nm in diameter with demonstrated therapeutic potentials. Limitations such as the natural biodistribution (mainly concentrated in the liver and spleen) and short plasma half-life of EVs present significant challenges to their clinical translation. In recent years, growing research indicated that engineered EVs with enhanced targeting to lesion sites have markedly promoted therapeutic efficacy. However, there is a dearth of systematic knowledge on the recent advances in engineering EVs for targeted delivery. Herein, we provide an overview of the targeting mechanisms, engineering techniques, and clinical translations of natural and engineered EVs in therapeutic applications. Enrichment of EVs at lesion sites may be achieved through the recognition of tissue markers, pathological changes, and the circumvention of mononuclear phagocyte system (MPS). Alternatively, external stimuli, including magnetic fields and ultrasound, may also be employed. EV engineering techniques that fulfill targeting functions includes genetic engineering, membrane fusion, chemical modification and physical modification. A comparative statistical analysis was conducted to elucidate the discrepancies between the diverse techniques on size, morphology, stability, targeting and therapeutic efficacy in vitro and in vivo. Additionally, a summary of the registered clinical trials utilizing EVs from 2010 to 2023 has been provided, with a full discussion on the perspectives. This review provides a comprehensive overview of the mechanisms and techniques associated with targeted delivery of EVs in therapeutic applications to advocate further explorations of engineered EVs and accelerate their clinical applications.

Insulin-inspired hippocampal neuron-targeting technology for protein drug delivery

Hippocampal neurons can be the first to be impaired with neurodegenerative disorders, including Alzheimer's disease (AD). Most drug candidates for causal therapy of AD cannot either enter the brain or accumulate around hippocampal neurons. Here, we genetically engineered insulin-fusion proteins, called hippocampal neuron-targeting (Ht) proteins, for targeting protein drugs to hippocampal neurons because insulin tends to accumulate in the neuronal cell layers of the hippocampus. In vitro examinations clarified that insulin and Ht proteins were internalized into the cultured hippocampal neurons through insulin receptor-mediated macropinocytosis. Cysteines were key determinants of the delivery of Ht proteins to hippocampal neurons, and insulin B chain mutant was most potent in delivering cargo proteins. In vivo accumulation of Ht proteins to hippocampal neuronal layers occurred after intracerebroventricular administration. Thus, hippocampal neuron-targeting technology can provide great help for developing protein drugs against neurodegenerative disorders.

4R-cembranoid suppresses glial cells inflammatory phenotypes and prevents hippocampal neuronal loss in LPS-treated mice

Chronic neuroinflammation has been implicated in neurodegenerative disease pathogenesis. A key feature of neuroinflammation is neuronal loss and glial activation, including microglia and astrocytes. 4R-cembranoid (4R) is a natural compound that inhibits hippocampal pro-inflammatory cytokines and increases memory function in mice. We used the lipopolysaccharide (LPS) injection model to study the effect of 4R on neuronal density and microglia and astrocyte activation. C57BL/6J wild-type mice were injected with LPS (5 mg/kg) and 2 h later received either 4R (6 mg/kg) or vehicle. Mice were sacrificed after 72 h for analysis of brain pathology. Confocal images of brain sections immunostained for microglial, astrocyte, and neuronal markers were used to quantify cellular hippocampal phenotypes and neurons. Hippocampal lysates were used to measure the expression levels of neuronal nuclear protein (NeuN), inducible nitrous oxide synthase (iNOS), arginase-1, thrombospondin-1 (THBS1), glial cell-derived neurotrophic factor (GDNF), and orosomucoid-2 (ORM2) by western blot. iNOS and arginase-1 are widely used protein markers of pro- and anti-inflammatory microglia, respectively. GDNF promotes neuronal survival, and ORM2 and THBS1 are astrocytic proteins that regulate synaptic plasticity and inhibit microglial activation. 4R administration significantly reduced neuronal loss and the number of pro-inflammatory microglia 72 h after LPS injection. It also decreased the expression of the pro-inflammatory protein iNOS while increasing arginase-1 expression, supporting its anti-inflammatory role. The protein expression of THBS1, GDNF, and ORM2 was increased by 4R. Our data show that 4R preserves the integrity of hippocampal neurons against LPS-induced neuroinflammation in mice.

Potential of oligonucleotide- and protein/peptide-based therapeutics in the management of toxicant/stressor-induced diseases

Exposure to toxicants/stressors has been linked to the development of many human diseases. They could affect various cellular components, such as DNA, proteins, lipids, and non-coding RNAs (ncRNA), thereby triggering various cellular pathways, particularly oxidative stress, inflammatory responses, and apoptosis, which can contribute to pathophysiological states. Accordingly, modulation of these pathways has been the focus of numerous investigations for managing related diseases. The involvement of various ncRNAs, such as small interfering RNA (siRNA), microRNAs (miRNA), and long non-coding RNAs (lncRNA), as well as various proteins and peptides in mediating these pathways, provides many target sites for pharmaceutical intervention. In this regard, various oligonucleotide- and protein/peptide-based therapies have been developed to treat toxicity-induced diseases, which have shown promising results in vitro and in vivo. This comprehensive review provides information about various aspects of toxicity-related diseases including their causing factors, main underlying mechanisms and intermediates, and their roles in pathophysiological states. Particularly, it highlights the principles and mechanisms of oligonucleotide- and protein/peptide-based therapies in the treatment of toxicity-related diseases. Furthermore, various issues of oligonucleotides and proteins/peptides for clinical usage and potential solutions are discussed.

Intranasal Delivery of Anti-Apoptotic siRNA Complexed with Fas-Signaling Blocking Peptides Attenuates Cellular Apoptosis in Brain Ischemia

Ischemic stroke-induced neuronal cell death leads to the permanent impairment of brain function. The Fas-mediating extrinsic apoptosis pathway and the cytochrome c-mediating intrinsic apoptosis pathway are two major molecular mechanisms contributing to neuronal injury in ischemic stroke. In this study, we employed a Fas-blocking peptide (FBP) coupled with a positively charged nona-arginine peptide (9R) to form a complex with negatively charged siRNA targeting Bax (FBP9R/siBax). This complex is specifically designed to deliver siRNA to Fas-expressing ischemic brain cells. This complex enables the targeted inhibition of Fas-mediating extrinsic apoptosis pathways and cytochrome c-mediating intrinsic apoptosis pathways. Specifically, the FBP targets the Fas/Fas ligand signaling, while siBax targets Bax involved in mitochondria disruption in the intrinsic pathway. The FBP9R carrier system enables the delivery of functional siRNA to hypoxic cells expressing the Fas receptor on their surface-a finding validated through qPCR and confocal microscopy analyses. Through intranasal (IN) administration of FBP9R/siCy5 to middle cerebral artery occlusion (MCAO) ischemic rat models, brain imaging revealed the complex specifically localized to the Fas-expressing infarcted region but did not localize in the non-infarcted region of the brain. A single IN administration of FBP9R/siBax demonstrated a significant reduction in neuronal cell death by effectively inhibiting Fas signaling and preventing the release of cytochrome c. The targeted delivery of FBP9R/siBax represents a promising alternative strategy for the treatment of brain ischemia.

Protein kinase C delta regulates mononuclear phagocytes and hinders response to immunotherapy in cancer

Mononuclear phagocytes (MPs) play a crucial role in tissue homeostasis; however, MPs also contribute to tumor progression and resistance to immune checkpoint blockade (ICB). Targeting MPs could be an effective strategy to enhance ICB efficacy. We report that protein kinase C delta (PKCδ), a serine/threonine kinase, is abundantly expressed by MPs in human and mouse tumors. PKCδ-/- mice displayed reduced tumor progression compared to wild types, with increased response to anti-PD-1. Tumors from PKCδ-/- mice demonstrated TH1-skewed immune response including increased antigen presentation and T cell activation. Depletion of MPs in vivo altered tumor growth in control but not PKCδ-/- mice. Coinjection of PKCδ-/- M2-like macrophages with cancer cells into wild-type mice markedly delayed tumor growth and significantly increased intratumoral T cell activation compared to PKCδ+/+ controls. PKCδ deficiency reprogrammed MPs by activating type I and type II interferon signaling. Thus, PKCδ might be targeted to reprogram MPs to augment ICB efficacy.

Overcoming delivery barriers for RNA therapeutics in the treatment of rheumatoid arthritis

RNA therapeutics can manipulate gene expression or protein production, making them suitable for treating a wide range of diseases. Theoretically, any disease that has a definite biological target would probably find feasible therapeutic approach from RNA-based therapeutics. Numerous clinical trials using RNA therapeutics fighting against cancer, infectious diseases or inherited diseases have been reported and achieved desirable therapeutic efficacy. So far, encouraging findings from various animal experimental studies have also confirmed the great potential of RNA-based therapies in the treatment of rheumatic arthritis (RA). However, the in vivo multiple physiological barriers still seriously compromise the therapeutic efficacy of RNA drugs. Thus, safe and effective delivery strategies for RNA therapeutics are quite essential for their further and wide application in RA therapy. In this review, we will discuss the recent progress achieved using RNA-based therapeutics and focus on delivery strategies that can overcome the in vivo delivery barriers in RA treatment. Furthermore, discussion about the existing problems in current RNA delivery systems for RA therapy has been also included here.

Nanoparticles and cytokine response

Synthetic nanoparticles (NPs) are non-viral equivalents of viral gene delivery systems that are actively explored to deliver a spectrum of nucleic acids for diverse range of therapies. The success of the nanoparticulate delivery systems, in the form of efficacy and safety, depends on various factors related to the physicochemical features of the NPs, as well as their ability to remain "stealth" in the host environment. The initial cytokine response upon exposure to nucleic acid bearing NPs is a critical component of the host response and, unless desired, should be minimized to prevent the unintended consequences of NP administration. In this review article, we will summarize the most recent literature on cytokine responses to nanoparticulate delivery systems and identify the main factors affecting this response. The NP features responsible for eliciting the cytokine response are articulated along with other factors related to the mode of therapeutic administration. For diseases arising from altered cytokine pathophysiology, attempts to silence the individual components of cytokine response are summarized in the context of different diseases, and the roles of NP features on this respect are presented. We finish with the authors' perspective on the possibility of engineering NP systems with controlled cytokine responses. This review is intended to sensitize the reader with important issues related to cytokine elicitation of non-viral NPs and the means of controlling them to design improved interventions in the clinical setting.

Extracellular vesicle-based delivery of silencing sequences for the treatment of Machado-Joseph disease/spinocerebellar ataxia type 3

Machado-Joseph disease (MJD)/spinocerebellar ataxia type 3 (SCA3) is the most common autosomal dominantly inherited ataxia worldwide. It is caused by an over-repetition of the trinucleotide CAG within the ATXN3 gene, which confers toxic properties to ataxin-3 (ATXN3) species. RNA interference technology has shown promising therapeutic outcomes but still lacks a non-invasive delivery method to the brain. Extracellular vesicles (EVs) emerged as promising delivery vehicles due to their capacity to deliver small nucleic acids, such as microRNAs (miRNAs). miRNAs were found to be enriched into EVs due to specific signal motifs designated as ExoMotifs. In this study, we aimed at investigating whether ExoMotifs would promote the packaging of artificial miRNAs into EVs to be used as non-invasive therapeutic delivery vehicles to treat MJD/SCA3. We found that miRNA-based silencing sequences, associated with ExoMotif GGAG and ribonucleoprotein A2B1 (hnRNPA2B1), retained the capacity to silence mutant ATXN3 (mutATXN3) and were 3-fold enriched into EVs. Bioengineered EVs containing the neuronal targeting peptide RVG on the surface significantly decreased mutATXN3 mRNA in primary cerebellar neurons from MJD YAC 84.2 and in a novel dual-luciferase MJD mouse model upon daily intranasal administration. Altogether, these findings indicate that bioengineered EVs carrying miRNA-based silencing sequences are a promising delivery vehicle for brain therapy.

Research Advances in Nucleic Acid Delivery System for Rheumatoid Arthritis Therapy

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that affects the lives of nearly 1% of the total population worldwide. With the understanding of RA, more and more therapeutic drugs have been developed. However, lots of them possess severe side effects, and gene therapy may be a potential method for RA treatment. A nanoparticle delivery system is vital for gene therapy, as it can keep the nucleic acids stable and enhance the efficiency of transfection in vivo. With the development of materials science, pharmaceutics and pathology, more novel nanomaterials and intelligent strategies are applied to better and safer gene therapy for RA. In this review, we first summarized the existing nanomaterials and active targeting ligands used for RA gene therapy. Then, we introduced various gene delivery systems for RA treatment, which may enlighten the relevant research in the future.

A small-molecule inhibitor of Keap1-Nrf2 interaction attenuates sepsis by selectively augmenting the antibacterial defence of macrophages at infection sites

BACKGROUND

Macrophages at infection sites are considered as the promising therapeutic targets to prevent sepsis development. The Nrf2/Keap1 system acts as a critical modulator of the antibacterial activity of macrophages. Recently, Keap1-Nrf2 protein-protein interaction (PPI) inhibitors have emerged as safer and stronger Nrf2 activators; however, their therapeutic potential in sepsis remains unclear. Herein, we report a unique heptamethine dye, IR-61, as a Keap1-Nrf2 PPI inhibitor that preferentially accumulates in macrophages at infection sites.

METHODS

A mouse model of acute lung bacterial infection was used to investigate the biodistribution of IR-61. SPR study and CESTA were used to detect the Keap1 binding behaviour of IR-61 in vitro and in cells. Established models of sepsis in mice were used to determine the therapeutic effect of IR-61. The relationship between Nrf2 levels and sepsis outcomes was preliminarily investigated using monocytes from human patients.

FINDINGS

Our data showed that IR-61 preferentially accumulated in macrophages at infection sites, enhanced bacterial clearance, and improved outcomes in mice with sepsis. Mechanistic studies indicated that IR-61 potentiated the antibacterial function of macrophages by activating Nrf2 via direct inhibition of the Keap1-Nrf2 interaction. Moreover, we observed that IR-61 enhanced the phagocytic ability of human macrophages, and the expression levels of Nrf2 in monocytes might be associated with the outcomes of sepsis patients.

INTERPRETATIONS

Our study demonstrates that the specific activation of Nrf2 in macrophages at infection sites is valuable for sepsis management. IR-61 may prove to be a Keap1-Nrf2 PPI inhibitor for the precise treatment of sepsis.

FUNDING

This work was supported by the National Natural Science Foundation of China (Major program 82192884), the Intramural Research Project (Grants: 2018-JCJQ-ZQ-001 and 20QNPY018), and the Chongqing National Science Foundation (CSTB2022NSCQ-MSX1222).

Peptide-assembled nanoparticles targeting tumor cells and tumor microenvironment for cancer therapy

Tumor cells and corrupt stromal cells in the tumor microenvironment usually overexpress cancer-specific markers that are absent or barely detectable in normal cells, providing available targets for inhibiting the occurrence and development of cancers. It is noticeable that therapeutic peptides are emerging in cancer therapies and playing more and more important roles. Moreover, the peptides can be self-assembled and/or incorporated with polymeric molecules to form nanoparticles via non-covalent bond, which have presented appealing as well as enhanced capacities of recognizing targeted cells, responding to microenvironments, mediating internalization, and achieving therapeutic effects. In this review, we will introduce the peptide-based nanoparticles and their application advances in targeting tumor cells and stromal cells, including suppressive immune cells, fibrosis-related cells, and angiogenic vascular cells, for cancer therapy.

Nucleic acid drug vectors for diagnosis and treatment of brain diseases

Nucleic acid drugs have the advantages of rich target selection, simple in design, good and enduring effect. They have been demonstrated to have irreplaceable superiority in brain disease treatment, while vectors are a decisive factor in therapeutic efficacy. Strict physiological barriers, such as degradation and clearance in circulation, blood-brain barrier, cellular uptake, endosome/lysosome barriers, release, obstruct the delivery of nucleic acid drugs to the brain by the vectors. Nucleic acid drugs against a single target are inefficient in treating brain diseases of complex pathogenesis. Differences between individual patients lead to severe uncertainties in brain disease treatment with nucleic acid drugs. In this Review, we briefly summarize the classification of nucleic acid drugs. Next, we discuss physiological barriers during drug delivery and universal coping strategies and introduce the application methods of these universal strategies to nucleic acid drug vectors. Subsequently, we explore nucleic acid drug-based multidrug regimens for the combination treatment of brain diseases and the construction of the corresponding vectors. In the following, we address the feasibility of patient stratification and personalized therapy through diagnostic information from medical imaging and the manner of introducing contrast agents into vectors. Finally, we take a perspective on the future feasibility and remaining challenges of vector-based integrated diagnosis and gene therapy for brain diseases.

Applications of Nanoparticles in Alzheimer's Disease

With the rapid aging of the global population, the prevalence of neurodegenerative diseases has become a significant concern, with Alzheimer's disease (AD) being the most common. However, the clinical trials of many drugs targeting AD have failed due to the challenges posed by the blood-brain barrier (BBB), which makes intracerebral administration of drugs difficult. However, nanoparticles (NPs) may aid in the delivery of such drugs. NPs are materials with sizes between 1-100 nm that offer several advantages, such as improving biocompatibility, prolonging half-life, transporting large molecules, crossing the BBB to deliver to the central nervous system, and exhibiting good targeting ability. In addition to drug delivery, NPs also have excellent diagnostic potential, and multifunctional NPs can integrate the advantages of diagnosis, targeting, and treatment. This mini-review article provides an overview of NPs, including the composition of the carrier, strategies for crossing the BBB, and different targets of AD pathology, with the aim of providing guidance for the development prospects of NPs.

CNS Delivery of Nucleic Acid Therapeutics: Beyond the Blood-Brain Barrier and Towards Specific Cellular Targeting

Nucleic acid-based therapeutic molecules including small interfering RNA (siRNA), microRNA(miRNA), antisense oligonucleotides (ASOs), messenger RNA (mRNA), and DNA-based gene therapy have tremendous potential for treating diseases in the central nervous system (CNS). However, achieving clinically meaningful delivery to the brain and particularly to target cells and sub-cellular compartments is typically very challenging. Mediating cell-specific delivery in the CNS would be a crucial advance that mitigates off-target effects and toxicities. In this review, we describe these challenges and provide contemporary evidence of advances in cellular and sub-cellular delivery using a variety of delivery mechanisms and alternative routes of administration, including the nose-to-brain approach. Strategies to achieve subcellular localization, endosomal escape, cytosolic bioavailability, and nuclear transfer are also discussed. Ultimately, there are still many challenges to translating these experimental strategies into effective and clinically viable approaches for treating patients.

Modulating Expression of Endogenous Interleukin 1 Beta in the Acute Phase of the Pilocarpine Model of Epilepsy May Change Animal Survival

The pilocarpine-induced (PILO) model has helped elucidate the electrophysiological and molecular aspects related to mesial temporal lobe epilepsy. It has been suggested that the extensive cell death and edema observed in the brains of these animals could be induced by increased inflammatory responses, such as the rapid release of the inflammatory cytokine interleukin 1 beta (Il1b). In this study, we investigate the role of endogenous Il1b in the acute phase of the PILO model. Our aim is twofold. First, we want to determine whether it is feasible to silence Il1b in the central nervous system using a non-invasive procedure. Second, we aim to investigate the effect of silencing endogenous Il1b and its antagonist, Il1rn.We used RNA interference applied non-invasively to knockdown Il1b and its endogenous antagonist Il1rn. We found that knocking down Il1b prior to pilocarpine injection increased the mortality rate of treated animals. Furthermore, we observed that, when exposing the animals to more Il1b by silencing its endogenous antagonist Il1rn, there was a better response to status epilepticus with decreased animal mortality in the acute phase of the PILO model. Thus, we show the feasibility of using a novel, less invasive approach to study genes involved in the inflammatory response in the central nervous system. Furthermore, our results provide suggestive evidence that modulating endogenous Il1b improves animal survival in the acute phase of the PILO model and may have effects that extend into the chronic phase.

Regulation of activated microglia and macrophages by systemically administered DNA/RNA heteroduplex oligonucleotides

Microglial activation followed by recruitment of blood-borne macrophages into the central nervous system (CNS) aggravates neuroinflammation. Specifically, in multiple sclerosis (MS) as well as in experimental autoimmune encephalomyelitis (EAE), a rodent model of MS, activated microglia and macrophages (Mg/Mφ) promote proinflammatory responses and expand demyelination in the CNS. However, a potent therapeutic approach through the systemic route for regulating their functions has not yet been developed. Here, we demonstrate that a systemically injected DNA/RNA heteroduplex oligonucleotide (HDO), composed of an antisense oligonucleotide (ASO) and its complementary RNA, conjugated to cholesterol (Chol-HDO) distributed more efficiently to demyelinating lesions of the spinal cord in EAE mice with significant gene silencing than the parent ASO. Importantly, systemic administration of Cd40-targeting Chol-HDO improved clinical signs of EAE with significant downregulation of Cd40 in Mg/Mφ. Furthermore, we successfully identify that macrophage scavenger receptor 1 (MSR1) is responsible for the uptake of Chol-HDO by Mg/Mφ of EAE mice. Overall, our findings demonstrate the therapeutic potency of systemically administered Chol-HDO to regulate activated Mg/Mφ in neuroinflammation.

Targeted delivery to macrophages and dendritic cells by chemically modified mannose ligand-conjugated siRNA

Extrahepatic delivery of small interfering RNAs (siRNAs) may have applications in the development of novel therapeutic approaches. However, reports on such approaches are limited, and the scarcity of reports concerning the systemically targeted delivery of siRNAs with effective gene silencing activity presents a challenge. We herein report for the first time the targeted delivery of CD206-targetable chemically modified mannose–siRNA (CMM–siRNA) conjugates to macrophages and dendritic cells (DCs). CMM–siRNA exhibited a strong binding ability to CD206 and selectively delivered contents to CD206-expressing macrophages and DCs. Furthermore, the conjugates demonstrated strong gene silencing ability with long-lasting effects and protein downregulation in CD206-expressing cells in vivo. These findings could broaden the use of siRNA technology, provide additional therapeutic opportunities, and establish a basis for further innovative approaches for the targeted delivery of siRNAs to not only macrophages and DCs but also other cell types.

Joint synovial macrophages as a potential target for intra-articular treatment of osteoarthritis-related pain

Osteoarthritis is the most common form of joint disease and is one of the leading causes of chronic pain. Given the multi-factorial nature, numerous efforts have been made to clarify the multiple factors impacting the pain symptoms and joint pathology, including synovial macrophages in particular. Accumulating evidence from studies involving human participants and experimental animal models suggests that accumulating macrophages in synovial tissue are implicated in peripherally mediated pain sensitization of affected joints in osteoarthritis. Crosstalk between synovial macrophages and the innervating primary nociceptive neurons is thought to contribute to this facilitated pain processing by the peripheral nervous system. Due to high plasticity and complexity of synovial macrophages in the joint, safe therapies targeting single cells or molecules are currently lacking. Using advanced technologies (such as single-cell RNA sequencing and mass cytometry), studies have shown that diverse subpopulations of synovial macrophages exist in the distinct synovial microenvironments of specific osteoarthritis subtypes. Considerable progress has been made in delineating the molecular mechanisms of various subsets of synovial macrophages in the development of osteoarthritis. To develop a novel intra-articular treatment paradigm targeting synovial macrophages, we have summarized in this review the recent advances in identifying the functional consequences of synovial macrophage sub-populations and understanding of the molecular mechanisms driving macrophage-mediated remodeling.

Nanoparticles Carrying NF-κB p65-Specific siRNA Alleviate Colitis in Mice by Attenuating NF-κB-Related Protein Expression and Pro-Inflammatory Cellular Mediator Secretion

Ulcerative colitis is a disease that causes inflammation and ulcers in the colon and which is typically recurrent, and NF-κB proteins are important players during disease progression. Here, we assess the impact of silica-coated calcium phosphate nanoparticles carrying encapsulated siRNA against NF-κB p65 on a murine model of colitis. To this end, nanoparticles were injected intravenously (2.0 mg siRNA/kg body weight) into mice after colitis induction with dextran sulfate sodium or healthy ones. The disease activity index, the histopathological impact on the colon, the protein expression of several NF-κB-associated players, and the mediator secretion (colon tissue, blood) were analyzed. We found that the nanoparticles effectively alleviated the clinical and histopathological features of colitis. They further suppressed the expression of NF-κB proteins (e.g., p65, p50, p52, p100, etc.) in the colon. They finally attenuated the local (colon) or systemic (blood) pro-inflammatory mediator secretion (e.g., TNF-α, IFN-β, MCP-1, interleukins, etc.) as well as the leucocyte load of the spleen and mesenteric lymph nodes. The nanoparticle biodistribution in diseased animals was seen to pinpoint organs containing lymphoid entities (appendix, intestine, lung, etc.). Taken together, the nanoparticle-related silencing of p65 NF-κB protein expression could well be used for the treatment of ulcerative colitis in the future.

Delivery strategies of RNA therapeutics to leukocytes

Harnessing RNA-based therapeutics for cancer, inflammation, and viral diseases is hindered by poor delivery of therapeutic RNA molecules. Targeting leukocytes to treat these conditions holds great promise, as they are key participants in their initiation, drug response, and treatment. The various extra- and intra-cellular obstacles that impediment the clinical implementation of therapeutic RNA can be overcome by utilizing drug delivery systems. However, delivery of therapeutic RNA to leukocytes poses an even greater challenge as these cells are difficult to reach and transfect upon systemic administration. This review briefly describes the existing successful delivery strategies that efficiently target leukocytes in vivo and discuss their potential clinical applicability.

Extracellular vesicle-mediated delivery of circDYM alleviates CUS-induced depressive-like behaviours

Major depressive disorder (MDD) is the most prevalent psychiatric disorder worldwide and severely limits psychosocial function and quality of life, but no effective medication is currently available. Circular RNAs (circRNAs) have been revealed to participate in the MDD pathological process. Targeted delivery of circRNAs without blood-brain barrier (BBB) restriction for remission of MDD represents a promising approach for antidepressant therapy. In this study, RVG-circDYM-extracellular vesicles (RVG-circDYM-EVs) were engineered to target and preferentially transfer circDYM to the brain, and the effect on the pathological process in a chronic unpredictable stress (CUS) mouse model of depression was investigated. The results showed that RVG-circDYM-EVs were successfully purified by ultracentrifugation from overexpressed circDYM HEK 293T cells, and the characterization of RVG-circDYM-EVs was successfully demonstrated in terms of size, morphology and specific markers. Beyond demonstrating proof-of-concept for an RNA drug delivery technology, we observed that systemic administration of RVG-circDYM-EVs efficiently delivered circDYM to the brain, and alleviated CUS-induced depressive-like behaviours, and we discovered that RVG-circDYM-EVs notably inhibited microglial activation, BBB leakiness and peripheral immune cells infiltration, and attenuated astrocyte disfunction induced by CUS. CircDYM can bind mechanistically to the transcription factor TAF1 (TATA-box binding protein associated factor 1), resulting in the decreased expression of its downstream target genes with consequently suppressed neuroinflammation. Taken together, our findings suggest that extracellular vesicle-mediated delivery of circDYM is effective for MDD treatment and promising for clinical applications.

The brain targeted delivery of programmed cell death 4 specific siRNA protects mice from CRS-induced depressive behavior

Depression is one of the most common psychiatric disorders. Recently, studies demonstrate that antidepressants generating BDNF not only maintain synaptic signal transmission but also repress neuroinflammatory cytokines such as IL-6 and IL-1β. Therefore, promoting BDNF expression provides a strategy for the treatment of depression. Our recent research has indicated that programmed cell death 4 (Pdcd4) is a new target for antidepressant treatment by facilitating BDNF. Herein, we modified Pdcd4 specific small interfering RNA (siPdcd4) with the rabies virus glycoprotein peptide (RVG/siPdcd4) which enables it cross the blood-brain barrier (BBB). We found that RVG/siPdcd4 complex was selectively delivered to neurons and microglia and silenced the expression of Pdcd4, thereby up-regulating the level of BDNF and down-regulating IL-6 and IL-1β expression. More importantly, RVG/siPdcd4 injection attenuated synaptic plasticity impairment and protected mice from CRS-induced depressive behavior. These findings suggest that RVG/siPdcd4 complex is a potential therapeutic medicine for depression.

A Nanomule Peptide Carrier Delivers siRNA Across the Intact Blood-Brain Barrier to Attenuate Ischemic Stroke

The blood-brain barrier (BBB) hinders the distribution of therapeutics intended for treatment of neuroinflammation (NI) of the central nervous system. A twelve-amino acid peptide that transcytoses the BBB, termed MTfp, was chemically conjugated to siRNA to create a novel peptide-oligonucleotide conjugate (POC), directed to downregulate NOX4, a gene thought responsible for oxidative stress in ischemic stroke. The MTfp-NOX4 POC has the ability to cross the intact BBB and knockdown NOX4 expression in the brain. Following induction of ischemic stroke, animals pretreated with the POC exhibited significantly smaller infarcts; accompanied by increased protection against neurological deterioration and improved recovery. The data demonstrates that the MTfp can act as a nanomule to facilitate BBB transcytosis of siRNAs; where the NOX-4 specific siRNA moiety can elicit effective therapeutic knockdown of a gene responsible for oxidative stress in the central nervous system. This study is the first to conclusively demonstrate both siRNA-carrier delivery and therapeutic efficacy in any CNS disease model where the BBB remains intact and thus offers new avenues for potential treatments of oxidative stress underlying neuroinflammation in a variety of neuropathologies that are currently refractory to existing therapies.

Street RABV Induces the Cholinergic Anti-inflammatory Pathway in Human Monocyte-Derived Macrophages by Binding to nAChr α7

Rabies virus (RABV) is able to reach the central nervous system (CNS) without triggering a strong immune response, using multiple mechanisms to evade and suppress the host immune system. After infection via a bite or scratch from a rabid animal, RABV comes into contact with macrophages, which are the first antigen-presenting cells (APCs) that are recruited to the area and play an essential role in the onset of a specific immune response. It is poorly understood how RABV affects macrophages, and if the interaction contributes to the observed immune suppression. This study was undertaken to characterize the interactions between RABV and human monocyte-derived macrophages (MDMs). We showed that street RABV does not replicate in human MDMs. Using a recombinant trimeric RABV glycoprotein (rRABV-tG) we showed binding to the nicotinic acetylcholine receptor alpha 7 (nAChr α7) on MDMs, and confirmed the specificity using the nAChr α7 antagonist alpha-bungarotoxin (α-BTX). We found that this binding induced the cholinergic anti-inflammatory pathway (CAP), characterized by a significant decrease in tumor necrosis factor α (TNF-α) upon LPS challenge. Using confocal microscopy we found that induction of the CAP is associated with significant cytoplasmic retention of nuclear factor κB (NF-κB). Co-cultures of human MDMs exposed to street RABV and autologous T cells further revealed that the observed suppression of MDMs might affect their function as T cell activators as well, as we found a significant decrease in proliferation of CD8+ T cells and an increased production of the anti-inflammatory cytokine IL-10. Lastly, using flow cytometric analysis we observed a significant increase in expression of the M2-c surface marker CD163, hinting that street RABV might be able to affect macrophage polarization. Taken together, these results show that street RABV is capable of inducing an anti-inflammatory state in human macrophages, possibly affecting T cell functioning.

Optimizing the Intracellular Delivery of Therapeutic Anti-inflammatory TNF-α siRNA to Activated Macrophages Using Lipidoid-Polymer Hybrid Nanoparticles

RNA interference (RNAi) has an unprecedented potential as a therapeutic strategy for reversibly silencing the expression of any gene. Therapeutic delivery of the RNAi mediator, i.e., small interfering RNA (siRNA), can be used to address diseases characterized by gene overexpression, for example inflammatory conditions like chronic obstructive pulmonary disease (COPD). Macrophages play a key role in COPD pathogenesis and are recruited to the airways and lung parenchyma, where they release proinflammatory cytokines, e.g., tumor necrosis factor-alpha (TNF-α). Hence, targeting TNF-α with siRNA is a promising therapeutic approach for COPD management. However, a safe and effective delivery system is required for delivery of TNF-α siRNA into the cytosol of hard-to-transfect macrophages. The purpose of this study was to optimize the intracellular delivery of TNF-α siRNA to the lipopolysaccharide-activated murine macrophage cell line RAW 264.7 using lipidoid-polymer hybrid nanoparticles (LPNs) composed of the lipid-like transfection agent lipidoid 5 (L₅) and the biodegradable polymer poly (D,L-lactide-co-glycolide). Applying a quality-by-design approach, the influence of critical formulation variables, i.e., the L₅ content and the L₅:siRNA ratio (w/w), on critical quality attributes (CQAs) was investigated systematically using risk assessment and design of experiments, followed by delineation of an optimal operating space (OOS). The CQAs were identified based on the quality target product profile and included size, polydispersity index, zeta potential, encapsulation efficiency and loading for achieving efficient and safe TNF-α gene silencing in activated RAW 264.7 cells. Formulations inducing efficient gene silencing and low cytotoxicity were identified, and the optimal formulations displayed L₅ contents of 15 and 20% (w/w), respectively, and an L₅:siRNA weight ratio of 15:1. All tested formulations within the OOS mediated efficient and sequence-specific TNF-α gene silencing in RAW 264.7 cells at TNF-α-siRNA concentrations, which were significantly lower than the concentrations required of non-encapsulated TNF-α-siRNA, highlighting the benefit of the delivery system. The results also demonstrate that increasing the loading of siRNA into the delivery system does not necessarily imply enhanced gene silencing. This opens new avenues for further exploitation of LPNs as a robust platform technology for delivering TNF-α siRNA to macrophages, e.g., in the management of COPD.

Macrophage reprogramming for therapy

Dysfunction of the immune system underlies a plethora of human diseases, requiring the development of immunomodulatory therapeutic intervention. To date, most strategies employed have been focusing on the modification of T lymphocytes, and although remarkable improvement has been obtained, results often fall short of the intended outcome. Recent cutting-edge technologies have highlighted macrophages as potential targets for disease control. Macrophages play central roles in development, homeostasis and host defence, and their dysfunction and dysregulation have been implicated in the onset and pathogenesis of multiple disorders including cancer, neurodegeneration, autoimmunity and metabolic diseases. Recent advancements have led to a greater understanding of macrophage origin, diversity and function, in both health and disease. Over the last few years, a variety of strategies targeting macrophages have been developed and these open new therapeutic opportunities. Here, we review the progress in macrophage reprogramming in various disorders and discuss the potential implications and challenges for macrophage-targeted approaches in human disease.

Improvement of obesity-associated disorders by a small-molecule drug targeting mitochondria of adipose tissue macrophages

Pro-inflammatory activation of adipose tissue macrophages (ATMs) is causally linked to obesity and obesity-associated disorders. A number of studies have demonstrated the crucial role of mitochondrial metabolism in macrophage activation. However, there is a lack of pharmaceutical agents to target the mitochondrial metabolism of ATMs for the treatment of obesity-related diseases. Here, we characterize a near-infrared fluorophore (IR-61) that preferentially accumulates in the mitochondria of ATMs and has a therapeutic effect on diet-induced obesity as well as obesity-associated insulin resistance and fatty liver. IR-61 inhibits the classical activation of ATMs by increasing mitochondrial complex levels and oxidative phosphorylation via the ROS/Akt/Acly pathway. Taken together, our findings indicate that specific enhancement of ATMs oxidative phosphorylation improves chronic inflammation and obesity-related disorders. IR-61 might be an anti-inflammatory agent useful for the treatment of obesity-related diseases by targeting the mitochondria of ATMs.

Adipose tissue macrophages are central to controlling inflammation in the context of obesity. Here the authors present a new infrared dye (IR-61) that accumulates in the mitochondria of these cells resulting in anti-inflammatory effects that counter obesity-associated pathology in mice.

Engineered Extracellular Vesicles Loaded With miR-124 Attenuate Cocaine-Mediated Activation of Microglia

MicroRNA-124 (miR-124), a brain-enriched microRNA, is known to regulate microglial quiescence. Psychostimulants such as cocaine have been shown to activate microglia by downregulating miR-124, leading, in turn, to neuroinflammation. We thus rationalized that restoring the levels of miR-124 could function as a potential therapeutic approach for cocaine-mediated neuroinflammation. Delivering miRNA based drugs in the brain that are effective and less invasive, however, remains a major challenge in the field. Herein we engineered extracellular vesicles (EVs) and loaded them with miR-124 for delivery in the brain. Approach involved co-transfection of mouse dendritic cells with Dicer siRNA and RVG-Lamp2b plasmid to deplete endogenous miRNAs and for targeting the CNS, respectively. Mouse primary microglia (mPm) were treated with purified engineered EVs loaded with either Cy5-miR-124 or Cy5-scrambled miRNA oligos in the presence or absence of cocaine followed by assessing EV uptake and microglial activation. In vivo studies involved pretreating mice intranasally with engineered EVs followed by cocaine injection (20 mg/kg, i.p.). mPm exposed to EV-miR-124 exhibited reduced expression of miR-124 targets - TLR4 and STAT3 as well as ERK-1/2 and Iba1. In cocaine administered mice, EV-Cy5-miR-124 delivered intranasally were detected in the CNS and significantly reduced the expression of inflammatory markers TLR4, MYD88, STAT3 and NF-kB p65 while also downregulating the microglial activation marker, Iba1. Collectively, these findings suggest that engineered EVs can deliver miR-124 into the CNS, thereby alleviating cocaine-mediated microglial activation. Manipulating EV miRNAs can thus be envisioned as an efficient means for delivery of RNA-based therapeutics to target organs.

Therapeutic siRNA: state of the art

RNA interference (RNAi) is an ancient biological mechanism used to defend against external invasion. It theoretically can silence any disease-related genes in a sequence-specific manner, making small interfering RNA (siRNA) a promising therapeutic modality. After a two-decade journey from its discovery, two approvals of siRNA therapeutics, ONPATTRO® (patisiran) and GIVLAARI™ (givosiran), have been achieved by Alnylam Pharmaceuticals. Reviewing the long-term pharmaceutical history of human beings, siRNA therapy currently has set up an extraordinary milestone, as it has already changed and will continue to change the treatment and management of human diseases. It can be administered quarterly, even twice-yearly, to achieve therapeutic effects, which is not the case for small molecules and antibodies. The drug development process was extremely hard, aiming to surmount complex obstacles, such as how to efficiently and safely deliver siRNAs to desired tissues and cells and how to enhance the performance of siRNAs with respect to their activity, stability, specificity and potential off-target effects. In this review, the evolution of siRNA chemical modifications and their biomedical performance are comprehensively reviewed. All clinically explored and commercialized siRNA delivery platforms, including the GalNAc (N-acetylgalactosamine)-siRNA conjugate, and their fundamental design principles are thoroughly discussed. The latest progress in siRNA therapeutic development is also summarized. This review provides a comprehensive view and roadmap for general readers working in the field.

Reduction of inflammation in a chronic periodontitis model in rats by TNF-α gene silencing with a topically applied siRNA-loaded calcium phosphate paste

We developed a calcium phosphate-based paste containing siRNA against TNF-α and investigated its anti-inflammatory and bone-healing effects in vitro and in vivo in a rat periodontitis model. The bioactive spherical CaP/PEI/siRNA/SiO₂ nanoparticles had a core diameter of 40-90 nm and a positive charge (+23 mV) that facilitated cellular uptake. The TNF- α gene silencing efficiency of the nanoparticles in J774.2 monocytes, gingival-derived cells, and bone marrow-derived cells was 12 ± 2%, 36 ± 8%, and 35 ± 22%, respectively. CaP/PEI/siRNA/SiO₂ nanoparticles cancelled the suppression of alkaline phosphatase (ALP) activity in LPS-stimulated bone marrow-derived cells. In vivo, ALP mRNA was up-regulated, TNF-α mRNA was down-regulated, and the amount of released TNF-α was significantly reduced after topical application of the calcium phosphate-based paste containing siRNA-loaded nanoparticles. The number of TNF-α-positive cells in response to CaP/PEI/siRNA/SiO₂ nanoparticle application was lower than that observed in the absence of siRNA. Elevated ALP activity and numerous TRAP-positive cells (osteoclasts) were observed in response to the application of all calcium phosphate pastes. These results demonstrate that local application of a paste consisting of siRNA-loaded calcium phosphate nanoparticles successfully induces TNF-α silencing in vitro and in vivo and removes the suppression of ALP activity stimulated by inflammation. STATEMENT OF SIGNIFICANCE: We developed a calcium phosphate-based paste containing nanoparticles loaded with siRNA against TNF-α. The nanoparticles had a core diameter of 40-90 nm and positive charge (+23 mV). The anti-inflammatory and osteoinductive effects of the paste were investigated in vitro and in vivo in a rat periodontitis model. In vitro, the TNF-α gene silencing efficiency of the nanoparticles in J774.2 monocytes, gingival-derived cells, and bone marrow-derived cells was 12 ± 2%, 36 ± 8%, and 35 ± 22%, respectively. The ALP activity of bone marrow-derived cells was recovered. In vivo, TNF-α mRNA was down-regulated and the amount of released TNF-α was significantly reduced, whereas the ALP mRNA was up-regulated. Elevated ALP activity and TRAP-positive cells were observed by immunohistochemistry.

Advances in Targeted Gene Delivery

Gene therapy has the potential to treat both acquired and inherited genetic diseases. Generally, two types of gene delivery vectors are used - viral vectors and non-viral vectors. Non-viral gene delivery systems have attracted significant interest (e.g. 115 gene therapies approved for clinical trials in 2018; clinicaltrials.gov) due to their lower toxicity, lack of immunogenicity and ease of production compared to viral vectors. To achieve the goal of maximal therapeutic efficacy with minimal adverse effects, the cell-specific targeting of non-viral gene delivery systems has attracted research interest. Targeting through cell surface receptors; the enhanced permeability and retention effect, or pH differences are potential means to target genes to specific organs, tissues, or cells. As for targeting moieties, receptorspecific ligand peptides, antibodies, aptamers and affibodies have been incorporated into synthetic nonviral gene delivery vectors to fulfill the requirement of active targeting. This review provides an overview of different potential targets and targeting moieties to target specific gene delivery systems.

Enhanced delivery of Mycobacterium tuberculosis antigens to antigen presenting cells using RVG peptide

Among the various strategies to improve vaccines against infectious diseases, targeting of antigens to dendritic cells (DCs), which are professional antigen presenting cells (APCs), has received increased attention in recent years. Here, we investigated whether a synthetic peptide region named RVG, originated from Rabies Virus Glycoprotein that binds to the α-7 subunit of the nicotinic acetylcholine receptors (AchR-α7) of APCs, could be used for the delivery of Mycobacterium tuberculosis (Mtb) peptide antigens to DCs and macrophages. Mouse bone marrow derived DCs (BMDCs) and human THP-1 macrophages stimulated with RVG fused peptide epitopes 85B241 and 85B96 (represent Ag85B241-256 and Ag85B96-111, respectively) from antigen 85B (Ag85B) of Mtb showed enhanced antigen presentation as compared to unfused peptide epitopes and BCG. Further, BMDCs stimulated with RVG fused 85B241 showed higher levels of IL-12 positive cells. Consistent with in vitro data, splenocytes of mice immunized with RVG-85B241 showed increased number of antigen specific IFN-γ, IL-2, and TNF-α producing cells in relation to splenocytes from mice immunized with 85B241 alone. These results suggest that RVG may be a promising tool to develop effective alternate vaccines against tuberculosis (TB).

Transportan-derived cell-penetrating peptide delivers siRNA to inhibit replication of influenza virus in vivo

Introduction

In this study, we report on the development of an effective delivery system for siRNAs; a novel cell-penetrating peptide (CPP), T9(dR), obtained from transportan (TP), was used for in vivo and in vitro testing.

Methods

In this study, toxicity of T9(dR) and TP and efficient delivery of siRNA were tested in 293T, MDCK, RAW, and A549 cells. Furthermore, T9(dR)- and TP-delivered siRNAs against nucleoprotein (NP) gene segment of influenza virus (siNP) were studied in both cell lines and mice.

Results

Gel retardation showed that T9(dR) effectively condensed siRNA into nanoparticles sized between 350 and 550 nm when the mole ratio of T9(dR) to siRNA was ≥4:1. In vitro studies demonstrated that T9(dR) successfully delivered siRNA with low cellular toxicity into several cell lines. It was also observed that T9(dR)-delivered siRNAs inhibited replication of influenza virus more efficiently as compared to that delivered by TP into the MDCK and A549 cells. It was also noticed that when given a combined tail vein injection of siNP and T9(dR) or TP, all mice in the 50 nmol siNP group infected with PR8 influenza virus survived and showed weight recovery at 2 weeks post-infection.

Conclusion

This study indicates that T9(dR) is a promising siRNA delivery tool with potential application for nucleotide drug delivery.

Pathogenic Role of Immune Cells in Rheumatoid Arthritis: Implications in Clinical Treatment and Biomarker Development

Rheumatoid arthritis (RA) is a chronic, autoimmune, systemic, inflammatory disorder that affects synovial joints, both small and large joints, in a symmetric pattern. This disorder usually does not directly cause death but significantly reduces the quality of life and life expectancy of patients if left untreated. There is no cure for RA but, patients are usually on long-term disease modifying anti-rheumatic drugs (DMARDs) to suppress the joint inflammation, to minimize joint damage, to preserve joint function, and to keep the disease in remission. RA is strongly associated with various immune cells and each of the cell type contributes differently to the disease pathogenesis. Several types of immunomodulatory molecules mainly cytokines secreted from immune cells mediate pathogenesis of RA, hence complicating the disease treatment and management. There are various treatments for RA depending on the severity of the disease and more importantly, the patient’s response towards the given drugs. Early diagnosis of RA and treatment with (DMARDs) are known to significantly improve the treatment outcome of patients. Sensitive biomarkers are crucial in early detection of disease as well as to monitor the disease activity and progress. This review aims to discuss the pathogenic role of various immune cells and immunological molecules in RA. This review also highlights the importance of understanding the immune cells in treating RA and in exploring novel biomarkers.

In vivo methods for acute modulation of gene expression in the central nervous system

Accurate and timely expression of specific genes guarantees the healthy development and function of the brain. Indeed, variations in the correct amount or timing of gene expression lead to improper development and/or pathological conditions. Almost forty years after the first successful gene transfection in in vitro cell cultures, it is currently possible to regulate gene expression in an area-specific manner at any step of central nervous system development and in adulthood in experimental animals in vivo, even overcoming the very poor accessibility of the brain. Here, we will review the diverse approaches for acute gene transfer in vivo, highlighting their advantages and disadvantages with respect to the efficiency and specificity of transfection as well as to brain accessibility. In particular, we will present well-established chemical, physical and virus-based approaches suitable for different animal models, pointing out their current and future possible applications in basic and translational research as well as in gene therapy.

Combination of NF-kB targeted siRNA and methotrexate in a hybrid nanocarrier towards the effective treatment in rheumatoid arthritis

Background

The transcription factor NF-kB plays an important role in the pathogenesis of rheumatoid arthritis (RA). Effective treatment of RA is hindered due to the lack of specificity of small molecules in the inflamed joints. In this study, we aimed to develop a unique hybrid-nanoparticles system comprised of calcium phosphate/liposome to deliver NF-kB-targeted siRNA and methotrexate (MTX) to diseased site.

Results

We have successfully demonstrated that the combination of siRNA and MTX in a calcium phosphate/liposome-based hybrid nanocarrier could effectively treat the RA. We have showed that folate receptor-targeted nanocarrier system significantly suppression the arthritis progression in mice model. Substantial accumulation of F-siRML was observed in LPS-activated macrophages. These kind of activated macrophages are generally present in the RA and osteoarthritis and folate-targeted nanoparticle enables the effective accumulation of therapeutics in the diseased site. The combinational nanoparticles effectively blocked the NF-kB signaling pathways and reduced the expression of pro-inflammatory cytokines. Furthermore, siRML and F-siRML did not show any decrease in the lymphocyte count indicating that it can avoid the adverse effect of MTX.

Conclusion

Therefore, siRML and F-siRML provides unique benefits of excellent therapeutic efficacy with excellent safety profile in the arthritic mice and could be an promising approach in the treatment of rheumatoid arthritis.

Electronic supplementary material

The online version of this article (10.1186/s12951-018-0382-x) contains supplementary material, which is available to authorized users.

Nanocapsule-mediated cytosolic siRNA delivery for anti-inflammatory treatment

The use of nanoparticle-stabilized nanocapsules for cytosolic siRNA delivery for immunomodulation in vitro and in vivo is reported. These NPSCs deliver siRNA directly to the cytosol of macrophages in vitro with concomitant knockdown of gene expression. In vivo studies showed directed delivery of NPSCs to the spleen, enabling gene silencing of macrophages, with preliminary studies showing 70% gene knockdown at a siRNA dose of 0.28 mg/kg. Significantly, the delivery of siRNA targeting tumor necrosis factor-α efficiently silenced TNF-α expression in LPS-challenged mice, demonstrating efficacy in modulating immune response in an organ-selective manner. This research highlights the potential of the NPSC platform for targeted immunotherapy and further manipulation of the immune system.

Lipid nanoparticles with minimum burst release of TNF-α siRNA show strong activity against rheumatoid arthritis unresponsive to methotrexate

TNF-α siRNA has shown promising therapeutic benefits in animal models of rheumatoid arthritis. However, there continues to be a need for siRNA delivery systems that have high siRNA encapsulation efficiency and minimum burst release of TNF-α siRNA, and can target inflamed tissues after intravenous administration. Herein we report a novel acid-sensitive sheddable PEGylated solid-lipid nanoparticle formulation of TNF-α-siRNA, AS-TNF-α-siRNA-SLNs, prepared by incorporating lipophilized TNF-α-siRNA into solid-lipid nanoparticles composed of biocompatible lipids such as lecithin and cholesterol. The nanoparticles are approximately 120 nm in diameter, have a high siRNA encapsulation efficiency (>90%) and a minimum burst release of siRNA (<5%), and increase the deilvery of the siRNA in chronic inflammation sites in mouse models, including in a mouse model with collagen-induced arthritis. Importantly, in a mouse model of collagen antibody-induced arthritis that does not respond to methotrexate therapy, intravenous injection of the AS-TNF-α-siRNA-SLNs significantly reduced paw thickness, bone loss, and histopathological scores. These findings highlight the potential of using this novel siRNA nanoparticle formulation to effectively treat arthritis, potentially in patients who do not respond adequately to methotrexate.

The Cholinergic Anti-Inflammatory Response and the Role of Macrophages in HIV-Induced Inflammation

Macrophages are phagocytic immune cells that protect the body from foreign invaders and actively support the immune response by releasing anti- and proinflammatory cytokines. A seminal finding revolutionized the way macrophages are seen. The expression of the neuronal alpha7 nicotinic acetylcholine receptor (α7-nAChR) in macrophages led to the establishment of the cholinergic anti-inflammatory response (CAR) in which the activation of this receptor inactivates macrophage production of proinflammatory cytokines. This novel neuroimmune response soon began to emerge as a potential target to counteract inflammation during illness and infection states. Human immunodeficiency virus (HIV)-infected individuals suffer from chronic inflammation that persists even under antiretroviral therapy. Despite the CAR’s importance, few studies involving macrophages have been performed in the HIV field. Evidence demonstrates that monocyte-derived macrophages (MDMs) recovered from HIV-infected individuals are upregulated for α7-nAChR. Moreover, in vitro studies demonstrate that addition of an HIV viral constituent, gp120_IIIB, to uninfected MDMs also upregulates the α7-nAChR. Importantly, contrary to what was expected, activation of upregulated α7-nAChRs in macrophages does not reduce inflammation, suggesting a CAR disruption. Although it is reasonable to consider this receptor as a pharmacological target, additional studies are necessary since its activity seems to differ from that observed in neurons.

Small Interfering RNA-Mediated Control of Virus Replication in the CNS Is Therapeutic and Enables Natural Immunity to West Nile Virus

No vaccines or therapeutics are licensed for West Nile virus (WNV), a mosquito-transmitted neuroencephalitic flavivirus. The small interfering RNA siFvE^JW targets a conserved sequence within the WNV E protein and limits virus infection. Using a rabies virus-derived neuron-targeting peptide (RVG9R) and an intranasal route for delivering siFvE^JW to the CNS, we demonstrate that treatment of WNV-infected mice at late stages of neuroinvasive disease results in recovery. Selectively targeting virus in the CNS lowers viral burdens in the brain, reduces neuropathology, and results in a 90% survival rate at 5-6 days post-infection (when viral titers peak in the CNS), while placebo-treated mice succumb by days 9-10. Importantly, CNS virus clearance is achieved by humoral and cell-mediated immune responses to WNV infection in peripheral tissues, which also engender sterilizing immunity against subsequent WNV infection. These results indicate that intranasal RVG9R-siRNA treatment offers efficient late-stage therapy and facilitates natural long-term immunity against neuroinvasive flaviviruses.

Targeted delivery of nano-PTX to the brain tumor-associated macrophages

Nanoparticles containing mixed lipid monolayer shell, biodegradable polymer core and rabies virus glycoprotein (RVG) peptide as brain targeting ligand, were developed for brain targeted delivery of paclitaxel (PTX) to treat malignant glioma. RVG conjugated PTX loaded NPs (RVG-PTX-NPs) had the desirable size (~140 nm), narrow size distribution and spherical shape. RVG-PTX-NPs showed poor uptake by neurons and selective targeting to the brain tumor associated macrophages (TAMs) with controlled release and tumor specific toxicity. In vivo studies revealed that RVG-PTX-NPs were significant to cross the blood-brain barrier (BBB) and had specific targeting to the brain. Most importantly, RVG-PTX-NPs showed effectiveness for anti-glioma therapy on human glioma of mice model. We concluded that RVG-PTX-NPs provided an effective approach for brain-TAMs targeted delivery for the treatment of glioma.