Mesenchymal Stem Cell Engagement Modulates Neuroma Microenviroment in Rats and Humans and Prevents Postamputation Pain

Postamputation pain is currently managed unsatisfactorily with neuron-targeted pharmacological and interventional therapies. Non-neuronal pain mechanisms have emerged as crucial factors in the development and persistence of postamputation pain. Consequently, these mechanisms offer exciting prospects as innovative therapeutic targets. We examined the hypothesis that engaging mesenchymal stem cells (MSCs) would foster local neuroimmune interactions, leading to a potential reduction in postamputation pain. We utilized an ex vivo neuroma model from a phantom limb pain patient to uncover that the oligodeoxynucleotide IMT504 engaged human primary MSCs to promote an anti-inflammatory microenvironment. Reverse translation experiments recapitulated these effects. Thus, in an in vivo rat model, IMT504 exhibited strong efficacy in preventing autotomy (self-mutilation) behaviors. This effect was linked to a substantial accumulation of MSCs in the neuroma and associated dorsal root ganglia and the establishment of an anti-inflammatory phenotype in these compartments. Centrally, this intervention reduced glial reactivity in the dorsal horn spinal cord, demonstrating diminished nociceptive activity. Accordingly, the exogenous systemic administration of MSCs phenocopied the behavioral effects of IMT504. Our findings underscore the mechanistic relevance of MSCs and the translational therapeutic potential of IMT504 to engage non-neuronal cells for the prevention of postamputation pain. PERSPECTIVE: The present study suggests that IMT504-dependent recruitment of endogenous MSCs within severely injured nerves may prevent post-amputation pain by modifying the inflammatory scenario at relevant sites in the pain pathway. Reinforcing data in rat and human tissues supports the potential therapeutic value of IMT504 in patients suffering postamputation pain.

Intranasal treatment with CpG-B oligodeoxynucleotides protects CBA mice from lethal equine herpesvirus 1 challenge by an innate immune response

Equine herpesvirus 1 (EHV-1) is the causative agent of a number of equine disease manifestations, including severe disease of the central nervous system, respiratory infections, and abortion storms. Our results showed that intranasal treatment with CpG-B oligodeoxynucleotides (ODN 1826) protected CBA mice from pathogenic EHV-1 RacL11 challenge. The IFN-γ gene and seven interferon-stimulated genes (ISGs) were upregulated 39.4- to 260.3-fold at 8 h postchallenge in the lungs of RacL11-challenged mice that had been treated with CpG-B ODN. Interestingly, IFN-γ gene expression was upregulated by 26-fold upon RacL11 challenge in CpG-B ODN-treated mice lungs as compared to that of CpG-A ODN (ODN 1585)-treated mice lungs; however, the seven ISGs were upregulated by 2.4-5.0-fold, suggesting that IFN-γ is a major factor in the protection of CBA mice from the lethal challenge. Pre-treatment with IFN-γ significantly reduced EHV-1 yield in murine alveolar macrophage MH-S cells, but not in mouse lung epithelial MLE12 cells. These results suggest that CpG-B ODN may be used as a prophylactic agent in horses and provide a basis for more effective treatment of EHV-1 infection.

A novel antimicrobial peptide-derived vehicle for oligodeoxynucleotide delivery to inhibit TNF-α expression

Indolicidin (IL), an antimicrobial peptide, was investigated as a vehicle to promote oligodeoxynucleotides (ODNs) delivery. To increase charge density, IL was dimerized by adding a cysteine to its C or N terminus, which was denoted as ILC or CIL, respectively. In contrast to IL, cytotoxicity of ILC and CIL was significantly reduced because these dimeric peptides were longer than IL, which restricted their insertions to cell membrane. In contrast to ILC, CIL displayed well loading efficiency. These peptides were applied to deliver ODNs against tumor necrosis factor-α (TNF-α) because TNF-α is a pro-inflammatory cytokine which plays an important role in immunological diseases. Although IL/ODN slightly reduced TNF-α expression, the high cytotoxicity restricted its application window. Furthermore, ILC/ODN was incapable of inducing gene silence due to its low encapsulation efficiency and poor endosomal escape. In contrast, CIL exhibited excellent ODN transportation and the internalized CIL/ODN complexes may escape from endosomes. Therefore, TNF-α expression can be specifically reduced by CIL/ODN complexes, and the silence effect was maintained longer than 14 h. This study provides a useful strategy of peptide vehicle design, which may facilitate the delivery of not only ODN but also other oligonucleotides, including siRNA and miRNA, to promote gene silence application.

Recent advances in applying nanotechnologies for cancer immunotherapy

Cancer immunotherapy aimed at boosting cancer-specific immunoresponses to eradicate tumor cells has evolved as a new treatment modality. Nanoparticles incorporating antigens and immunomodulatory agents can activate immune cells and modulate the tumor microenvironment to enhance anti-tumor immunity. The nanotechnology approach has been demonstrated to be superior to standard formulations in in-vivo settings. In this article, we focus on recent advances made within the last 5 years in nanoparticle-based cancer immunotherapy, including peptide- and nucleic acid-based nanovaccines, nanomedicines containing an immunoadjuvant to activate anti-tumor immunity, nanoparticle delivery of immune checkpoint inhibitors and the combination of the above approaches. Encouraging results and new emerging nanotechnologies in drug delivery promise the continuous growth of this field and ultimately clinical translation of enhanced immunotherapy of cancer.

Atlanto-occipital catheterization of young rats for long-term drug delivery into the lumbar subarachnoid space combined with in vivo testing and electrophysiology in situ

BACKGROUND

Catheterization has been widely used in neuroscience and pain research for local drug delivery. Though different modifications were developed, the use of young animals for spinal catheterization remains limited because of a little success rate. A reliable technique is needed to catheterize young animals aimed for in vivo testing combined with spinal cord electrophysiology, often limited by animal age, to facilitate pain research.

NEW METHODS

We describe intrathecal catheterization of young rats (3-week-old) through atlanto-occipical approach for long-lasting drug delivery into the lumbar subarachnoid space. The technique represents a surgical approach of minimized invasiveness that requires PE-10 catheter and few equipment of standard laboratory use.

RESULTS

Behavioral assessments revealed that spinal catheterization does not change peripheral sensitivity of different modalities (thermal and mechanical) and gives no rise to locomotive deficit or anxiety-like behavior in young rats. The long-term administration of genetic material (oligodeoxynucleotides given up to 4days), examined both in vivo and in situ, produced no adverse effects on basal peripheral sensitivity, but changed the AMPA receptor-mediated currents in sensory interneurons of the spinal cord.

COMPARISON WITH EXISTING METHODS

Dissimilar to already described methods, the method is designed for the use of young rats for behavioral testing in vivo and/or spinal cord electrophysiology in situ.

CONCLUSIONS

A practical method for spinal catheterization of young animals designed for studies in vivo and in situ is proposed. The method is rapid and effective and should facilitate investigation of therapeutic effects on both systemic and subcellular levels, as an advantage over the existing methods.

Extraordinary thermal stability of an oligodeoxynucleotide octamer constructed from alternating 7-deaza-7-iodo guanine and 5-Iodocytosine base pairs - DNA duplex stabilization by halogen bonds?

A reinvestigation of the published X-ray crystal-structure analyses of 7-halogenated (Br, I) 8-aza-7-deaza-2'-deoxyguanosines Br(7) c(7) z(8) Gd ; 1a and I(7) c(7) z(8) Gd , 1b, as well as of the structurally related 7-deaza-7-iodo-2'-deoxy-β-D-ribofuranosyladenine (β-I(7) c(7) Ad ; 2=6e in Table 1) and its α-D-anomer (α-I(7) c(7) Ad ; 3) clearly revealed the existence of halogen bonds between corresponding halogen substituents and the adjacent N(3)-atoms of neighboring nucleoside molecules within the single crystals. These halogen bonds can be rationalized by the presence of a region of positive electrostatic potential, the σ-hole, on the outermost portion the halogen's surface, while the three unshared pairs of electrons produce a belt of negative electrostatic potential around the central part of the halogen substituent. The N(3) atoms of the halogenated nucleosides carry a partial negative charge. This novel type of bonding between nucleosides was tentatively used to explain the extraordinary high stability of oligodeoxynucleotides constructed from halogenated nucleotide building blocks.

Co-delivery of doxorubicin and siRNA by a simplified platform with oligodeoxynucleotides as a drug carrier

The greatest challenge in combining chemotherapy and gene therapy is the construction of a suitable platform for the co-delivery of the drug and the therapeutic gene. In this study, a simplified and effective system for the co-loading and intracellular co-delivery of doxorubicin (Dox) and siRNA was developed. Oligodeoxynucleotides with CGA repeating units (CGA-ODNs) were introduced to load Dox. The loading mechanism was based on the ability of Dox to intercalate within double-stranded 5'-GC-3' or 5'-CG-3' sequences. Poly(ethyleneimine) (PEI) was used to condense siRNA and Dox loaded CGA-ODNs (CGA-ODNs-Dox) to obtain Dox and siRNA co-loaded nanocomplexes (PEI/CGA-ODNs-Dox&siRNA, PDR). The cellular uptake of PDR in A549 and HepG2 cells was 39.52% and 36.78%, respectively, indicating that the co-loading and co-delivery effect was achieved through the mono-loading method. An in vitro drug release study indicated that CMCS-poly(ethylene glycol) (PEG)-NGR (CPN) modified PDR (CPN-PDR) displayed a pH-triggered drug release property due to the reversed surface charge of CMCS in an acidic environment. Cellular uptake studies also confirmed that the disassembly of CPN-PDR was induced by an acidic pH in the extracellular matrix. Moreover, lysosomal escape of both Dox and siRNA was observed. Successful accumulation of Dox in the cell nucleus and siRNA in the cytoplasm was also demonstrated. Consequently, the novel construction of a simplified loading method and high co-delivery efficiency was proven to be a promising platform for the co-delivery of drug and siRNA.

One-step synthesized immunostimulatory oligonucleotides-functionalized quantum dots for simultaneous enhanced immunogenicity and cell imaging

Unmethylated cytosine-phosphate-guanine (CpG) dinucleotides, normally occur in natural bacterial and viral genomes, show strong immunostimulatory activities to invading pathogens and have found widespread applications in both basic research and clinical trials. For the first time, we design a simple one-step synthesis of CpG-functionalized quantum dots (QDs), combining fascinating features of enhanced immunogenicity and cell imaging. The induction of QDs can greatly increase CpG uptake ability by TLR9-positive cells and elevate CpG stability against nuclease degradation. What is more, the outstanding optical properties also suggest that the CpG-QDs can serve as promising optical probes for the evaluation of the cellular uptake efficiency of the CpG motifs. To our best knowledge, this is the first report to use a facile one-pot synthesis strategy that allows the CpG-functionalized QDs to be prepared, which are able to serve as both the potent platform for immunotherapy and the fluorescent probes for intracellular imaging.

Hypoxic X-irradiation as an external stimulus for conformational change of oligodeoxynucleotides that possess disulfide bond and regulation of DNAzyme function

We achieved a conformational change of oligodeoxynucleotides and the regulation of DNAzyme function by means of a radiolytic strand exchange reaction of disulfide bond. We designed a system in which the DNAzyme function of RNA cleavage was suppressed by the hybridization of an inhibitor strand that possessed disulfide bond with an active DNAzyme. Hypoxic X-irradiation led to the recovery of RNA cleavage because the strand exchange reaction at the disulfide bond in inhibitor strand resulted in a release of inhibitor strand. This strategy may be applicable to gene regulation by hypoxic X-irradiation.

Small RNA- and DNA-based gene therapy for the treatment of liver cirrhosis, where we are?

Chronic liver diseases with different aetiologies rely on the chronic activation of liver injuries which result in a fibrogenesis progression to the end stage of cirrhosis and liver failure. Based on the underlying cellular and molecular mechanisms of a liver fibrosis, there has been proposed several kinds of approaches for the treatment of liver fibrosis. Recently, liver gene therapy has been developed as an alternative way to liver transplantation, which is the only effective therapy for chronic liver diseases. The activation of hepatic stellate cells, a subsequent release of inflammatory cytokines and an accumulation of extracellular matrix during the liver fibrogenesis are the major obstacles to the treatment of liver fibrosis. Several targeted strategies have been developed, such as antisense oligodeoxynucleotides, RNA interference and decoy oligodeoxynucleotides to overcome this barriers. With this report an overview will be provided of targeted strategies for the treatment of liver cirrhosis, and particularly, of the targeted gene therapy using short RNA and DNA segments.

Quantitative evaluation of the improvement in the pharmacokinetics of a nucleic acid drug delivery system by dynamic PET imaging with (18)F-incorporated oligodeoxynucleotides

Recently, we demonstrated the utility of positron emission tomography (PET) imaging-based pharmacokinetic evaluation studies for preclinical experiments and microdose clinical trials, mainly focused on low molecular weight compounds. In order to investigate the pharmacokinetics of nucleic acid drugs and their drug delivery systems (DDSs) in vivo by using PET imaging, we developed a novel and efficient method for radiolabeling oligodeoxynucleotides with the positron-emitting radionuclide (18)F (stoichiometry-focused Huisgen-type (18)F labeling). By using this method, we succeeded in synthesizing a variety of (18)F-labeled oligodeoxynucleotides with not only phosphodiesters (PO) in natural forms, but also phosphorothioate (PS) and bridged nucleic acid (BNA) in artificial forms, and then performed PET studies and radioactive metabolite analyses of these (18)F-labeled oligodeoxynucleotides. The tissue-distribution and dynamic changes in radioactivity showed significantly different profiles between these antisense oligodeoxynucleotides. The radioactivity of (18)F-labeled PO-DNA and PO-BNA rapidly accumulated in the kidneys and liver and then moved to the renal medulla, ureter, bladder, and intestine. However, the radioactivity of (18)F-labeled PS-DNA and PS-BNA, possessing PS backbone structures, was retained in the blood for relatively long periods and then gradually accumulated in the liver and kidneys. The metabolite analysis showed that (18)F-labeled PO-DNA rapidly degraded by 5min and (18)F-labeled PO-BNA gradually degraded over time by 60min. Conversely, (18)F-labeled PS-DNA and PS-BNA were shown to be much more stable. To demonstrate the usefulness of the PET imaging technique for evaluating the improved targeting potential of the DDS, we designed and synthesized a cholesterol-modified oligodeoxynucleotide, that we developed as an antisense nucleic acid drug against proprotein convertase subtilisin/kexin type 9 (PCSK9) for hypercholesterolemia therapy, and evaluated its pharmacokinetics using PET imaging. As expected, the (18)F-labeled cholesterol-modified PS-BNA-type oligodeoxynucleotide showed much higher and more rapid accumulation in the delivery target organ, that is, the liver, which encourages us to develop this drug. These results suggest that dynamic PET studies using (18)F-incorporated oligodeoxynucleotide synthesized by stoichiometry-focused Huisgen-type labeling is useful for quantitative pharmacokinetic evaluation of nucleic acid drugs and their delivery systems.