Polybutylcyanoacrylate nanoparticle-mediated neurotrophin-3 gene delivery for differentiating iPS cells into neurons

Electroconductive Collagen-Carbon Nanodots Nanocomposite Elicits Neurite Outgrowth, Supports Neurogenic Differentiation and Accelerates Electrophysiological Maturation of Neural Progenitor Spheroids

Neuronal disorders are characterized by the loss of functional neurons and disrupted neuroanatomical connectivity, severely impacting the quality of life of patients. This study investigates a novel electroconductive nanocomposite consisting of glycine-derived carbon nanodots (GlyCNDs) incorporated into a collagen matrix and validates its beneficial physicochemical and electro-active cueing to relevant cells. To this end, this work employs mouse induced pluripotent stem cell (iPSC)-derived neural progenitor (NP) spheroids. The findings reveal that the nanocomposite markedly augmented neuronal differentiation in NP spheroids and stimulate neuritogenesis. In addition, this work demonstrates that the biomaterial-driven enhancements of the cellular response ultimately contribute to the development of highly integrated and functional neural networks. Lastly, acute dizocilpine (MK-801) treatment provides new evidence for a direct interaction between collagen-bound GlyCNDs and postsynaptic N-methyl-D-aspartate (NMDA) receptors, thereby suggesting a potential mechanism underlying the observed cellular events. In summary, the findings establish a foundation for the development of a new nanocomposite resulting from the integration of carbon nanomaterials within a clinically approved hydrogel, toward an effective biomaterial-based strategy for addressing neuronal disorders by restoring damaged/lost neurons and supporting the reestablishment of neuroanatomical connectivity.

Induced pluripotent stem cells can improve thrombolytic effect of low-dose rt-PA after acute carotid thrombosis in rat

Background

Intravenous thrombolysis using recombinant tissue plasminogen activator (rt-PA) is the standard treatment for acute ischemic stroke. Standard-dose rt-PA (0.9 mg/kg) is known to achieve good recanalization but carries a high bleeding risk. Lower dose of rt-PA has less bleeding risk but carries a high re-occlusion rate. We investigate if induced pluripotent stem cells (iPSCs) can improve the thrombolytic effect of low-dose rt-PA (0.45 mg/kg).

Methods

Single irradiation with 6 mW/cm² light-emitting diode (LED) for 4 h at rat common carotid artery was used as thrombosis model according to our previous report. Endothelin-1 (ET-1), intercellular adhesion molecule-1 (ICAM-1), and interleukin 1 beta (IL-1 beta) were used as the inflammatory markers for artery endothelial injury. Angiopoietin-2 (AP-2), brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) were examined in artery wall and iPSCs culture. Animal ultrasound was used to evaluate the stenosis degree of common carotid artery before and at 2 h, 24 h, 4 days and 7 days after LED irradiation.

Results

After LED irradiation alone, there was a persistent occlusion from 2 h to 7 days. Standard-dose rt-PA alone could recanalize the occluded artery from 24 h to 7 days to stenotic degree ≤ 50%. Low-dose rt-PA or 1 × 10⁶ mouse iPSCs alone could not recanalize the occluded arteries from 2 h to 7 days. Combination use of low-dose rt-PA plus 1 × 10⁶ mouse iPSCs caused better recanalization from 24 h to 7 days. ET-1, ICAM-1 and IL-1 beta were strongly expressed after LED irradiation but reduced after iPSCs treatment. AP-2, BDNF and VEGF were rarely induced after LED irradiation but strongly expressed after iPSCs treatment. In vitro study showed iPSCs could express AP-2, BDNF and VEGF.

Conclusion

The adjuvant use of iPSCs may help improving the thrombolytic effect of low-dose rt-PA by suppressing inflammatory factors and inducing angiogenic trophic factors. Stem cells could be a potential regimen in acute thrombolytic therapy to improve recanalization and reduce complications.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02615-z.

Gene therapy with caspase-3 small interfering RNA-nanoparticles is neuroprotective after optic nerve damage

Apoptosis, a key mechanism of programmed cell death, is triggered by caspase-3 protein and lowering its levels with gene therapy may rescue cell death after central nervous system damage. We developed a novel, non-viral gene therapy to block caspase-3 gene expression using small interfering RNA (siRNA) delivered by polybutylcyanoacrylate nanoparticles (CaspNPs). In vitro CaspNPs significantly blocked caspase-3 protein expression in C6 cells, and when injected intraocularly in vivo, CaspNPs lowered retinal capsase-3 immunofluorescence by 57.9% in rats with optic nerve crush. Longitudinal, repeated retinal ganglion cell counts using confocal neuroimaging showed that post-traumatic cell loss after intraocular CaspNPs injection was only 36.1% versus 63.4% in lesioned controls. Because non-viral gene therapy with siRNA-nanoparticles can selectively silence caspace-3 gene expression and block apoptosis in post-mitotic neurons, siRNA delivery with nanoparticles may be promising for neuroprotection or restoration of central visual system damage and other neurological disorders. The animal study procedures were approved by the German National Act on the use of experimental animals (Ethic Committee Referat Verbraucherschutz, Veterinärangelegenheiten; Landesverwaltungsamt Sachsen-Anhalt, Halle, Germany, # IMP/G/01-1150/12 and # IMP/G/01-1469/17).

Nanomaterial-Based Approaches for Neural Regeneration

Mechanical, thermal, chemical, or ischemic injury of the central or peripheral nervous system results in neuron loss, neurite damage, and/or neuronal dysfunction, almost always accompanied by sensorimotor impairment which alters the patient's life quality. The regenerative strategies for the injured nervous system are currently limited and mainly allow partial functional recovery, so it is necessary to develop new and effective approaches for nervous tissue regenerative therapy. Nanomaterials based on inorganic or organic and composite or hybrid compounds with tunable physicochemical properties and functionality proved beneficial for the transport and delivery/release of various neuroregenerative-relevant biomolecules or cells. Within the following paragraphs, we will emphasize that nanomaterial-based strategies (including nanosized and nanostructured biomaterials) represent a promising alternative towards repairing and regenerating the injured nervous system.

Promoting Immune Efficacy of the Oral Helicobacter pylori Vaccine by HP55/PBCA Nanoparticles against the Gastrointestinal Environment

The immunogenicity of oral subunit vaccines is poor partly as a result of the harsh milieu of the gastrointestinal (GI) tract. For some pathogens that restrictedly inhabit the GI tract, a vaccine that works in situ may provide more potent protection than vaccines that operate parenterally. Yet, no appropriate delivery system is available for oral subunit vaccines. In this study, we designed HP55/poly( n-butylcyanoacrylate) (PBCA) nanoparticles (NPs) to carry Helicobacter pylori ( H. pylori) subunit vaccine CCF for oral administration in a prophylactic mice model. These NPs, which are synthesized using an interfacial polymerization method, protected the CCF antigen not only from the acidic pH in simulated gastric fluid (SGF, pH 1.2) but also from the proteolysis in simulated intestinal fluid (SIF, pH 7.4). Oral vaccination of mice with HP55/PBCA-CCF NPs promoted the production of serum antigen-specific antibodies, mucosal secretory IgA, and proinflammatory cytokines. Moreover, a Th1/Th17 response and augmented lymphocytes were found in the gastric tissue of HP55/PBCA-CCF NP-immunized mice, which might eventually limit H. pylori colonization. Collectively, these results indicate that HP55/PBCA NPs are promising carriers against the severe situation of the GI tract and thereby may be further utilized for other orally administrated vaccines or drugs.

Brain-Derived Neurotrophic Factor Loaded PS80 PBCA Nanocarrier for In Vitro Neural Differentiation of Mouse Induced Pluripotent Stem Cells

Brain derived neurotrophic factor (BDNF) can induce neural differentiation in stem cells and has the potential for repair of the nervous system. In this study, a polysorbate 80-coated polybutylcyanoacrylate nanocarrier (PS80 PBCA NC) was constructed to deliver plasmid DNAs (pDNAs) containing BDNF gene attached to a hypoxia-responsive element (HRE-cmvBDNF). The hypoxia-sensing mechanism of BDNF expression and inductiveness of the nano-formulation on mouse induced pluripotent stem cells (iPSCs) to differentiate into neurons following hypoxia was tested in vitro with immunofluorescent staining and Western blotting. The HRE-cmvBDNF appeared to adsorb onto the surface of PS80 PBCA NC, with a resultant mean diameter of 92.6 ± 1.0 nm and zeta potential of −14.1 ± 1.1 mV. HIF-1α level in iPSCs was significantly higher in hypoxia, which resulted in a 51% greater BDNF expression when transfected with PS80 PBCA NC/HRE-cmvBDNF than those without hypoxia. TrkB and phospho-Akt were also elevated which correlated with neural differentiation. The findings suggest that PS80 PBCA NC too can be endocytosed to serve as an efficient vector for genes coupled to the HRE in hypoxia-sensitive cells, and activation of the PI3/Akt pathway in iPSCs by BDNF is capable of neural lineage specification.

Dual delivery of siRNA and plasmid DNA using mesoporous silica nanoparticles to differentiate induced pluripotent stem cells into dopaminergic neurons

Nurr1 plasmid and Rex1 siRNA were complexed with positively charged FITC-conjugated mesoporous silica nanoparticles. The pNurr1–siRex1–FMSN(+) was delivered to induced pluripotent stem cells to enhance their differentiation into dopaminergic neurons.

Application of biomaterials to advance induced pluripotent stem cell research and therapy

Derived from any somatic cell type and possessing unlimited self-renewal and differentiation potential, induced pluripotent stem cells (iPSCs) are poised to revolutionize stem cell biology and regenerative medicine research, bringing unprecedented opportunities for treating debilitating human diseases. To overcome the limitations associated with safety, efficiency, and scalability of traditional iPSC derivation, expansion, and differentiation protocols, biomaterials have recently been considered. Beyond addressing these limitations, the integration of biomaterials with existing iPSC culture platforms could offer additional opportunities to better probe the biology and control the behavior of iPSCs or their progeny in vitro and in vivo. Herein, we discuss the impact of biomaterials on the iPSC field, from derivation to tissue regeneration and modeling. Although still exploratory, we envision the emerging combination of biomaterials and iPSCs will be critical in the successful application of iPSCs and their progeny for research and clinical translation.

Targeting delivery of liposomes with conjugated p-aminophenyl-α-d-manno-pyranoside and apolipoprotein E for inhibiting neuronal degeneration insulted with β-amyloid peptide

Liposomes with conjugated p-aminophenyl-α-d-manno-pyranoside (APMP) and apolipoprotein E (ApoE) (APMP-ApoE-liposomes) were employed to carry neuron growth factor (NGF) across the blood-brain barrier (BBB) and enhance the survival of degenerated neurons. APMP-ApoE-liposomes were used to deliver NGF across a monolayer of human brain-microvascular endothelial cells (HBMECs) regulated by human astrocytes (HAs) for rescuing SK-N-MC cells from an insult of β-amyloid peptide 1-42 (Aβ1-42). An increase in the APMP concentration enhanced the particle size, HBMEC and HA viability, permeability for propidium iodide (PI), and permeability for NGF, however, reduced the absolute value of zeta potential, APMP conjugation efficiency and transendothelial electrical resistance (TEER). In addition, an increase in the ApoE concentration increased the particle size, absolute value of zeta potential, HBMEC and HA viability, permeability for PI, permeability for NGF and SK-N-MC cell viability, however, decreased the ApoE conjugation efficiency and TEER. APMP and ApoE on liposomes can be promising surface moieties to carry NGF across the BBB, target degenerated neurons and inhibit Aβ1-42-induced neurotoxicity in Alzheimer's disease.