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Journal of Controlled Release :... Jun 2023Glutamate carboxypeptidase II (GCPII), localized on the surface of astrocytes and activated microglia, regulates extracellular glutamate concentration in the central...
Glutamate carboxypeptidase II (GCPII), localized on the surface of astrocytes and activated microglia, regulates extracellular glutamate concentration in the central nervous system (CNS). We have previously shown that GCPII is upregulated in activated microglia in the presence of inflammation. Inhibition of GCPII activity could reduce glutamate excitotoxicity, which may decrease inflammation and promote a 'normal' microglial phenotype. 2-(3-Mercaptopropyl) pentanedioic acid (2-MPPA) is the first GCPII inhibitor that underwent clinical trials. Unfortunately, immunological toxicities have hindered 2-MPPA clinical translation. Targeted delivery of 2-MPPA specifically to activated microglia and astrocytes that over-express GCPII has the potential to mitigate glutamate excitotoxicity and attenuate neuroinflammation. In this study, we demonstrate that 2-MPPA when conjugated to generation-4, hydroxyl-terminated polyamidoamine (PAMAM) dendrimers (D-2MPPA) localize specifically in activated microglia and astrocytes only in newborn rabbits with cerebral palsy (CP), not in controls. D-2MPPA treatment led to higher 2-MPPA levels in the injured brain regions compared to 2-MPPA treatment, and the extent of D-2MPPA uptake correlated with the injury severity. D-2MPPA was more efficacious than 2-MPPA in decreasing extracellular glutamate level in ex vivo brain slices of CP kits, and in increasing transforming growth factor beta 1 (TGF-β1) level in primary mixed glial cell cultures. A single systemic intravenous dose of D-2MPPA on postnatal day 1 (PND1) decreased microglial activation and resulted in a change in microglial morphology to a more ramified form along with amelioration of motor deficits by PND5. These results indicate that targeted dendrimer-based delivery specifically to activated microglia and astrocytes can improve the efficacy of 2-MPPA by attenuating glutamate excitotoxicity and microglial activation.
Topics: Animals; Rabbits; Cerebral Palsy; Dendrimers; Glutamic Acid; Brain; Microglia; Inflammation
PubMed: 37054778
DOI: 10.1016/j.jconrel.2023.04.017 -
Current Neuropharmacology 2019Alzheimer's disease (AD) is characterized by the loss of neurons. It is the most common cause of dementia in the elderly population accompanied by pathological... (Review)
Review
Alzheimer's disease (AD) is characterized by the loss of neurons. It is the most common cause of dementia in the elderly population accompanied by pathological degeneration of neurofibrillary tangles. Senile plaques are formed with beta-amyloid, hyperphosphoryled tau protein, apolipoprotein E and presenilin associated with protease activity [amyloid beta (Aβ), gamma-secretase (γS)]. The molecular mechanisms of neurodegeneration include apoptosis, oxidative stress (free radical generation), inflammation, immune activation, and others. The lack of effective treatments for AD stems mainly from the incomplete understanding the causes of AD. Currently, there are several hypotheses explaining the early mechanisms of AD pathogenesis. Recent years witnessed an unprecedented research growth in the area of nanotechnology, which uses atomic, molecular and macromolecular methods to create products in microscale (nanoscale) dimensions. In this article, we have discussed the role of nanotechnology in the development and improvement of techniques for early diagnosis and effective treatment of AD. Since AD pathology is practically irreversible, applications of disease-modifying treatments could be successful only if early diagnosis of AD is available. This review highlights various possibilities for the early diagnosis and therapy of AD and investigates potential adaptation of nanoparticles-dendrimers as a class of well-defined branched polymers that are chemically synthesized with a well-defined shape, size and nanoscopic physicochemical properties reminiscent of the proteins for the treatment of neurodegenerative diseases.
Topics: Alzheimer Disease; Animals; Antipsychotic Agents; Dendrimers; Humans; Nanoparticles
PubMed: 30227819
DOI: 10.2174/1570159X16666180918164623 -
Pharmacology Research & Perspectives Aug 2021The most crucial role of granulocyte colony-stimulating factor (G-CSF) in the body is to increase the strength of immune system. In recent years, research on the use of...
The most crucial role of granulocyte colony-stimulating factor (G-CSF) in the body is to increase the strength of immune system. In recent years, research on the use of nanoparticles in pharmaceuticals has been considered, most of which have been for drug-loading purposes. In this study, a novel G-CSF conjugated dendrimer was synthesized and characterized using different techniques. In vitro cytotoxicity was assessed on A549 and L929 cells, while abnormal toxicity was studied in mice. In vitro and in vivo biological activities were assessed in NFS60 cells and rats, respectively. In addition, in vivo distribution, plasma half-life, and histopathological effect were studied in rat. The characterization tests confirmed the successful conjugation. There was no difference between G-CSF cytotoxicity before and after conjugation, and no difference with the control group. No mice showed abnormal toxicity. Although in vitro biological activity revealed both conjugated and free G-CSF promote proliferation cells, biological activity decreased significantly after conjugation about one-third of the unconjugated form. Nonetheless, in vivo biological activity of conjugated G-CSF increased by more than 2.5-fold relative to the unconjugated form, totally. Fortunately, no histopathologic adverse effect was observed in vital rat tissues. Also, in vivo distribution of the conjugate was similar to the native protein with an enhanced terminal half-life. Our data revealed that G-CSF conjugated dendrimer could be considered as a candidate to improve the in vivo biological activity of G-CSF. Moreover, multivalent capability of the dendrimer may be used for other new potentials of G-CSF in future perspectives.
Topics: Animals; Cell Line; Dendrimers; Granulocyte Colony-Stimulating Factor; Heart; Humans; Kidney; Liver; Male; Mice; Rats; Tissue Distribution
PubMed: 34269522
DOI: 10.1002/prp2.826 -
Molecules (Basel, Switzerland) Nov 2018Dendrimers are nanoscopic compounds, which are monodispersed, and they are generally considered as homogeneous. PAMAM (polyamidoamine) was introduced in 1985, by Donald... (Review)
Review
Dendrimers are nanoscopic compounds, which are monodispersed, and they are generally considered as homogeneous. PAMAM (polyamidoamine) was introduced in 1985, by Donald A. Tomalia, as a new class of polymers, named 'starburst polymers'. This important contribution of Professor Tomalia opened a new research field involving nanotechnological approaches. From then on, many groups have been using PAMAM for diverse applications in many areas, including biomedical applications. The possibility of either linking drugs and bioactive compounds, or entrapping them into the dendrimer frame can improve many relevant biological properties, such as bioavailability, solubility, and selectivity. Directing groups to reach selective delivery in a specific organ is one of the advanced applications of PAMAM. In this review, structural and safety aspects of PAMAM and its derivatives are discussed, and some relevant applications are briefly presented. Emphasis has been given to gene delivery and targeting drugs, as advanced delivery systems using PAMAM and an incentive for its use on neglected diseases are briefly mentioned.
Topics: Animals; Biomedical Research; Chemistry Techniques, Synthetic; Dendrimers; Drug Carriers; Drug Delivery Systems; Gene Transfer Techniques; Humans; Nanotechnology; Structure-Activity Relationship; Tissue Distribution
PubMed: 30400134
DOI: 10.3390/molecules23112849 -
Biomolecules Sep 2019Dendrimers are nanosized, arborescent polymers of which size and structure are perfectly controlled. This is one reason why they are widely used for biomedical purposes....
Dendrimers are nanosized, arborescent polymers of which size and structure are perfectly controlled. This is one reason why they are widely used for biomedical purposes. Previously, we showed that a phosphorus-based dendrimer capped with anionic azabisphosphonate groups (so-called ABP dendrimer) has immuno-modulatory and anti-inflammatory properties towards human immune cells in vitro. Thereafter, we have shown that the ABP dendrimer has a promising therapeutic efficacy to treat models of chronic inflammatory disorders. On the way to clinical translation, the biodistribution and the safety of this drug-candidate has to be thoroughly assessed. In this article, we present preliminary non-clinical data regarding biodistribution, hematological safety, genotoxicity, maximal tolerated doses, and early cardiac safety of the ABP dendrimer. One of the genotoxicity assays reveals a potential mutagen effect of the item at a concentration above 200 µM, i.e., up to 100 times the active dose in vitro on human immune cells. However, as the results obtained for all the other assays show that the ABP dendrimer has promising biodistribution and safety profiles, there is no red flag raised to hamper the regulatory pre-clinical development of the ABP dendrimer.
Topics: Animals; Anti-Inflammatory Agents; Dendrimers; Female; Hydrazones; Mice; Rats; Safety; Tissue Distribution
PubMed: 31514434
DOI: 10.3390/biom9090475 -
Communications Biology May 2023Retinal Müller glia function as injury-induced stem-like cells in zebrafish but not mammals. However, insights gleaned from zebrafish have been applied to stimulate...
Retinal Müller glia function as injury-induced stem-like cells in zebrafish but not mammals. However, insights gleaned from zebrafish have been applied to stimulate nascent regenerative responses in the mammalian retina. For instance, microglia/macrophages regulate Müller glia stem cell activity in the chick, zebrafish, and mouse. We previously showed that post-injury immunosuppression by the glucocorticoid dexamethasone accelerated retinal regeneration kinetics in zebrafish. Similarly, microglia ablation enhances regenerative outcomes in the mouse retina. Targeted immunomodulation of microglia reactivity may therefore enhance the regenerative potential of Müller glia for therapeutic purposes. Here, we investigated potential mechanisms by which post-injury dexamethasone accelerates retinal regeneration kinetics, and the effects of dendrimer-based targeting of dexamethasone to reactive microglia. Intravital time-lapse imaging revealed that post-injury dexamethasone inhibited microglia reactivity. The dendrimer-conjugated formulation: (1) decreased dexamethasone-associated systemic toxicity, (2) targeted dexamethasone to reactive microglia, and (3) improved the regeneration enhancing effects of immunosuppression by increasing stem/progenitor proliferation rates. Lastly, we show that the gene rnf2 is required for the enhanced regeneration effect of D-Dex. These data support the use of dendrimer-based targeting of reactive immune cells to reduce toxicity and enhance the regeneration promoting effects of immunosuppressants in the retina.
Topics: Animals; Mice; Zebrafish; Microglia; Dendrimers; Retina; Immunosuppression Therapy; Dexamethasone; Mammals
PubMed: 37202450
DOI: 10.1038/s42003-023-04898-9 -
Molecular Pharmaceutics Mar 2013Dendrimers are a class of structurally defined macromolecules featured with a central core, a low-density interior formed by repetitive branching units, and a... (Review)
Review
Dendrimers are a class of structurally defined macromolecules featured with a central core, a low-density interior formed by repetitive branching units, and a high-density exterior terminated with surface functional groups. In contrast to their polymeric counterparts, dendrimers are nanosized and symmetrically shaped, which can be reproducibly synthesized on a large scale with monodispersity. These unique features have made dendrimers of increasing interest for drug delivery and other biomedical applications as nanoscaffold systems. Intended to address the potential use of dendrimers for the development of theranostic agents, which combines therapeutics and diagnostics in a single entity for personalized medicine, this review focuses on the reported methodologies of using dendrimer nanoscaffolds for targeted imaging and therapy of prostate cancer. Of particular interest, relevant chemistry strategies are discussed due to their important roles in the design and synthesis of diagnostic and therapeutic dendrimer-based nanoconjugates and potential theranostic agents, targeted or nontargeted. Given the developing status of nanoscaffolded theranostics, major challenges and potential hurdles are discussed along with the examples representing current advances.
Topics: Dendrimers; Drug Delivery Systems; Humans; Male; Prostatic Neoplasms; Radiochemistry
PubMed: 23294202
DOI: 10.1021/mp3005325 -
Journal of Internal Medicine Dec 2014Dendrimers are discrete nanostructures/nanoparticles with 'onion skin-like' branched layers. Beginning with a core, these nanostructures grow in concentric layers to... (Review)
Review
Dendrimers are discrete nanostructures/nanoparticles with 'onion skin-like' branched layers. Beginning with a core, these nanostructures grow in concentric layers to produce stepwise increases in size that are similar to the dimensions of many in vivo globular proteins. These branched tree-like concentric layers are referred to as 'generations'. The outer generation of each dendrimer presents a precise number of functional groups that may act as a monodispersed platform for engineering favourable nanoparticle-drug and nanoparticle-tissue interactions. These features have attracted significant attention in medicine as nanocarriers for traditional small drugs, proteins, DNA/RNA and in some instances as intrinsically active nanoscale drugs. Dendrimer-based drugs, as well as diagnostic and imaging agents, are emerging as promising candidates for many nanomedicine applications. First, we will provide a brief survey of recent nanomedicines that are either approved or in the clinical approval process. This will be followed by an introduction to a new 'nanoperiodic' concept which proposes nanoparticle structure control and the engineering of 'critical nanoscale design parameters' (CNDPs) as a strategy for optimizing pharmocokinetics, pharmocodynamics and site-specific targeting of disease. This paradigm has led to the emergence of CNDP-directed nanoperiodic property patterns relating nanoparticle behaviour to critical in vivo clinical translation issues such as cellular uptake, transport, elimination, biodistribution, accumulation and nanotoxicology. With a focus on dendrimers, these CNDP-directed nanoperiodic patterns are used as a strategy for designing and optimizing nanoparticles for a variety of drug delivery and imaging applications, including a recent dendrimer-based theranostic nanodevice for imaging and treating cancer. Several emerging preclinical dendrimer-based nanotherapy concepts related to inflammation, neuro-inflammatory disorders, oncology and infectious and ocular diseases are reviewed. Finally we will consider challenges and opportunities anticipated for future clinical translation, nanotoxicology and the commercialization of nanomedicine.
Topics: Clinical Trials as Topic; Dendrimers; Drug Approval; Drug Design; Humans; Molecular Structure; Nanomedicine
PubMed: 24995512
DOI: 10.1111/joim.12280 -
Nanomedicine (London, England) Oct 2014Dendrimers are emerging as potential nonviral vectors for the efficient delivery of drugs and nucleic acids to the brain and cancer cells. These polymers are highly... (Review)
Review
Dendrimers are emerging as potential nonviral vectors for the efficient delivery of drugs and nucleic acids to the brain and cancer cells. These polymers are highly branched, 3D macromolecules with modifiable surface functionalities and available internal cavities that make them attractive as delivery systems for drug and gene delivery applications. This article highlights the recent therapeutic advances resulting from the use of dendrimers for brain targeting and cancer treatment.
Topics: Brain; Brain Neoplasms; Dendrimers; Humans
PubMed: 25413857
DOI: 10.2217/nnm.14.130 -
International Journal of Molecular... Mar 2023Cancer is a result of abnormal cell proliferation. This pathology is a serious health problem since it is a leading cause of death worldwide. Current anti-cancer... (Review)
Review
Cancer is a result of abnormal cell proliferation. This pathology is a serious health problem since it is a leading cause of death worldwide. Current anti-cancer therapies rely on surgery, radiation, and chemotherapy. However, these treatments still present major associated problems, namely the absence of specificity. Thus, it is urgent to develop novel therapeutic strategies. Nanoparticles, particularly dendrimers, have been paving their way to the front line of cancer treatment, mostly for drug and gene delivery, diagnosis, and disease monitoring. This is mainly derived from their high versatility, which results from their ability to undergo distinct surface functionalization, leading to improved performance. In recent years, the anticancer and antimetastatic capacities of dendrimers have been discovered, opening new frontiers to dendrimer-based chemotherapeutics. In the present review, we summarize the intrinsic anticancer activity of different dendrimers as well as their use as nanocarriers in cancer diagnostics and treatment.
Topics: Humans; Dendrimers; Precision Medicine; Nanoparticles; Drug Carriers; Neoplasms; Drug Delivery Systems
PubMed: 36982503
DOI: 10.3390/ijms24065430