Stem cells from human apical papilla decrease neuro-inflammation and stimulate oligodendrocyte progenitor differentiation via activin-A secretion

Secondary damage following spinal cord injury leads to non-reversible lesions and hampering of the reparative process. The local production of pro-inflammatory cytokines such as TNF-α can exacerbate these events. Oligodendrocyte death also occurs, followed by progressive demyelination leading to significant tissue degeneration. Dental stem cells from human apical papilla (SCAP) can be easily obtained at the removal of an adult immature tooth. This offers a minimally invasive approach to re-use this tissue as a source of stem cells, as compared to biopsying neural tissue from a patient with a spinal cord injury. We assessed the potential of SCAP to exert neuroprotective effects by investigating two possible modes of action: modulation of neuro-inflammation and oligodendrocyte progenitor cell (OPC) differentiation. SCAP were co-cultured with LPS-activated microglia, LPS-activated rat spinal cord organotypic sections (SCOS), and LPS-activated co-cultures of SCOS and spinal cord adult OPC. We showed for the first time that SCAP can induce a reduction of TNF-α expression and secretion in inflamed spinal cord tissues and can stimulate OPC differentiation via activin-A secretion. This work underlines the potential therapeutic benefits of SCAP for spinal cord injury repair

Mechanisms of transport of polymeric and lipidic nanoparticles across the intestinal barrier.

Unraveling the mechanisms of nanoparticle transport across the intestinal barrier is essential for designing more efficient nanoparticles for oral administration. The physicochemical parameters of the nanoparticles (e.g., size, surface charge, chemical composition) dictate nanoparticle fate across the intestinal barrier. This review aims to address the most important findings regarding polymeric and lipidic nanoparticle transport across the intestinal barrier, including the evaluation of critical physicochemical parameters of nanoparticles that affect nanocarrier interactions with the intestinal barrier

Fate of polymeric nanocarriers for oral drug delivery

This review will focus on two polymeric nanocarriers: nanoparticles and micelles that have been studied for oral drug delivery at preclinical level. Their potential for oral drug delivery will first be illustrated. Then their mechanisms of uptake and their fate after oral delivery will be discussed. Future directions for oral delivery with nanocarriers will be analyzed with a special emphasis on optimal properties. The recent advances highlight the need to tune and to control their design with a good balance in their physicochemical properties and suggest that more sophisticated nanosystems will be developed for the oral delivery of drugs, biopharmaceuticals and vaccines, thanks to (i) the development of biocompatible polymers with tailored properties for oral drug delivery and formulation of nanocarriers, (ii) the understanding of cellular uptake mechanisms of polymeric nanocarriers, (iii) the novel techniques to study the fate of nanocarriers, polymers and drugs in the body and (iv) the identification of new ligands for targeted oral delivery. Major recent advances Recent advances in the (i) development of biocompatible polymers with tailored properties for oral drug delivery and nanocarrier formulation, (ii) the understanding of cellular uptake mechanisms of polymeric nanocarriers (iii) the new techniques to study fate of nanocarriers, polymers and drugs in the body and (iv) the identification of new ligands for targeted oral delivery have promoted the development of novel polymeric carriers for the oral delivery of drugs, biopharmaceuticals and vaccines

Bioadhesive nanoparticles of fungal chitosan for oral DNA delivery

Chitosan is an ideal candidate for oral DNA delivery due to its mucoadhesive properties. Chitosan (CS) produced under GMP conditions from fungal source was used to encapsulate a plasmid DNA coding for a reporter gene. Nanoparticles made by complex coacervation of CS and DNA had a size around 200nm, a positive zeta potential, a high association of DNA and protected the plasmid against nuclease degradation. Their transfection ability was assessed in differentiated intestinal Caco-2 cells. A N/P ratio of 4 and a DNA concentration of 8mug/ml were the optimal condtions leading to a transfection efficiency similar to the one reached with PEI-DNA complexes without cytotoxicity. M cells in monolayers influenced DNA uptake up to 8mug of DNA/ml when complexed with CS. Fungal trimethylchitosan was also tested but the complexes interactions were too strong to induce transfection in vitro. Confocal microscopy studies showed that CS/DNA and PEI/DNA nanoparticles were found at the apical surface of cell monolayers and DNA was co-localized within the nucleus. Quantification seemed to show that more DNA was associated with the cells when incubated with CS nanoparticles and that the presence of M cells slightly influenced DNA uptake when complexed with CS. In conclusion, we developed a new nanocarrier made of fungal CS promising for oral gene delivery and oral DNA vaccination

Retinoic acid-loaded NFL-lipid nanocapsules promote oligodendrogenesis in focal white matter lesion

Neural stem cells (NSC) are located in restricted areas of the central nervous system where they self-renew or differentiate into neurons, astrocytes or oligodendrocytes. The stimulation of endogenous NSC differentiation is one of the most promising therapeutic approaches to restore neurological function in patients affected by neurodegenerative diseases. Endogenous NSC of the subventricular zone (SVZ) can be selectively targeted by lipid nanocapsules (LNC) coated with the peptide NFLTBS.40-63 (NFL-LNC) after intra-lateral ventricular injection in the brain. NFL-LNC can potentially deliver active compounds to SVZ-NSC and thus promote their differentiation to treat neurodegenerative diseases. The aim of this work was to induce endogenous NSC differentiation by specifically delivering retinoic acid (RA) to SVZ-NSC via NFL-LNC. RA was successfully encapsulated into NFL-LNC and RA-NFL-LNC were incubated with primary rat SVZ-NSC. In vitro, RA-NFL-LNC decreased the number of nestin (NSC marker) cells and neurospheres compared to controls and increased the number of GalC (oligodendrocytic marker) cells. Then, RA-NFL-LNC were injected in the right lateral ventricle of a lysolecithin-induced rat focal white matter lesion model to evaluate their impact on oligodendrocyte repopulation and remyelination. RA-NFL-LNC significantly increased the percentage of mature oligodendrocytes, stimulating oligodendrogenesis, nearly to the pre-lesion levels. Thus, RA-NFL-LNC represent a promising nanomedicine to be further investigated in the treatment of demyelinating diseases

The therapeutic contribution of nanomedicine to treat neurodegenerative diseases via neural stem cell differentiation.

The discovery of adult neurogenesis drastically changed the therapeutic approaches of central nervous system regenerative medicine. The stimulation of this physiologic process can increase memory and motor performances in patients affected by neurodegenerative diseases. Neural stem cells contribute to the neurogenesis process through their differentiation into specialized neuronal cells. In this review, we describe the most important methods developed to restore neurological functions via neural stem cell differentiation. In particular, we focused on the role of nanomedicine. The application of nanostructured scaffolds, nanoparticulate drug delivery systems, and nanotechnology-based real-time imaging has significantly improved the safety and the efficacy of neural stem cell-based treatments. This review provides a comprehensive background on the contribution of nanomedicine to the modulation of neurogenesis via neural stem cell differentiation

NFL-lipid nanocapsules for brain neural stem cell targeting in vitro and in vivo.

The replacement of injured neurons by the selective stimulation of neural stem cells in situ represents a potential therapeutic strategy for the treatment of neurodegenerative diseases. The peptide NFL-TBS.40-63 showed specific interactions towards neural stem cells of the subventricular zone. The aim of our work was to produce a NFL-based drug delivery system able to target neural stem cells through the selective affinity between the peptide and these cells. NFL-TBS.40-63 (NFL) was adsorbed on lipid nanocapsules (LNC) whom targeting efficiency was evaluated on neural stem cells from the subventricular zone (brain) and from the central canal (spinal cord). NFL-LNC were incubated with primary neural stem cells in vitro or injected in vivo in adult rat brain (right lateral ventricle) or spinal cord (T10). NFL-LNC interactions with neural stem cells were different depending on the origin of the cells. NFL-LNC showed a preferential uptake by neural stem cells from the brain, while they did not interact with neural stem cells from the spinal cord. The results obtained in vivo correlate with the results observed in vitro, demonstrating that NFL-LNC represent a promising therapeutic strategy to selectively deliver bioactive molecules to brain neural stem cells

Nanoparticles as potential oral delivery systems of proteins and vaccines: a mechanistic approach.

Peptides and proteins remain poorly bioavailable upon oral administration. One of the most promising strategies to improve their oral delivery relies on their association with colloidal carriers, e.g. polymeric nanoparticles, stable in gastrointestinal tract, protective for encapsulated substances and able to modulate physicochemical characteristics, drug release and biological behavior. The mechanisms of transport of these nanoparticles across intestinal mucosa are reviewed. In particular, the influence of size and surface properties on their non-specific uptake or their targeted uptake by enterocytes and/or M cells is discussed. Enhancement of their uptake by appropriate cells, i.e. M cells by (i) modeling surface properties to optimize access to and transport by M cells (ii) identifying surface markers specific to human M cell allowing targeting to M cells and nanoparticles transcytosis is illustrated. Encouraging results upon in vivo testing are reported but low bioavailability and lack of control on absorbed dose slow down products development. Vaccines are certainly the most promising applications for orally delivered nanoparticles

New drug delivery system to target neural stem cells

in situ differentiation of endogenous neural stem cells (NSC) represents a potential therapeutic strategy to replace injured neuronal cells and to treat neurodegenerative diseases. Nevertheless, no work based on this approach has yet reached the clinical phase. The lack of NSC-targeting molecules primarily promotes the development of non-selective systems with limited effects on NSC differentiation. The aim of our work was to produce a drug delivery system able to selectively target endogenous NSC. The peptide NFL-TBS.40-63 (NFL) shows specific interactions with brain NSC, where it affects their properties and induces their differentiation [1]. Consequently, we produced an NFL-based drug delivery system to target those cells. The peptide was adsorbed on DiD-labeled lipid nanocapsules (LNC, NFL-LNC) and characterized by dynamic light scattering. NFL-LNC targeting efficiency was evaluated on brain and spinal cord NSC. NFL-LNC were incubated with primary NSC cultures, in vitro, and injected either in adult rat\u27s brain or spinal cord, in vivo. The determination of the targeting efficiency was performed by FACS for in vitro experiments, and by immunohistochemistry for in vivo study. Both in vitro and in vivo results show that NFL-LNC targeted brain NSC while they showed no affinity for spinal cord NSC [2]. While we are currently investigating the mechanisms involved in the preferential interactions of NFL-LNC with brain NSC, these data show that NFL-LNC is a promising therapeutic tool to selectively deliver bioactive molecules and to induce in situ NSC differentiation. References [1] Lépinoux-Chambaud, C., Barreau k., & Eyer J. The Neurofilament-Derived Peptide NFLTBS. 40-63 Targets Neural Stem Cells and Affects Their Properties. Stem Cells Transl Med (2016), 5: 901-913. [2] Carradori, D., Saulnier, P., Préat, V., des Rieux, A., & Eyer, J. (2016). NFL-lipid nanocapsules for brain neural stem cell targeting in vitro and in vivo. J. Control. Release, 238: 253-262

Helodermin-loaded nanoparticles: Characterization and transport across an in vitro model of the follicle-associated epithelium

M cells represent a potential portal for oral delivery of peptides and proteins due to their high endocytosis abilities. An in vitro model of human FAE (co-cultures) was used to evaluate the influence of M cells on the transport of free and encapsulated helodermin - a model peptide - across the intestinal epithelium. M cells enhanced transport of intact helodermin (18-fold, Papp 3 X 10(-6) cm s(-1)). As pegylation increased nanoparticle transport by M cells, helodermin was encapsulated in 200 mu nanoparticles containing PEG-b-PLA:PLGA 1:1. Stability of the selected formulation was demonstrated in simulated gastric and intestinal fluids. M cells increased the transport of helodermin encapsulated in these nanoparticles by a factor of 415, as compared to Caco-2 cells. Transport of free and encapsulated helodermin occurred most probably by endocytosis. In conclusion, M cells improved helodermin transport across the intestinal epithelium, confirming their high potential for oral delivery of peptides