Gene delivery in mouse auditory brainstem and hindbrain using in utero electroporation

Protocol for analysis of senescent neuronal stem cells in genetic-modified embryonic mice using in utero electroporation technique

Here, we present a detailed protocol for identification and analysis of senescent neuronal stem cells (NSCs) in the developing mouse embryonic neocortex using in utero electroporation. We describe the procedures of in utero electroporation and brain slide preparation. We then detail the procedures of senescence-associated β-galactosidase (SA-β-Gal) staining and immunofluorescence staining, followed by microscope imaging analysis. This combined approach can be used to study the in situ senescence of in utero electroporated embryonic brains.

For complete details on the use and execution of this protocol, please refer to Zhu et al. (2021).

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Identification of senescent cells in the developing brain by SA-β-Gal staining

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In utero electroporation of pCAG-Cre-GFP plasmid into NSCs in loxP embryonic brains

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SA-β-Gal and anti-GFP co-staining to identify the senescent NSCs in embryonic brain

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A modified protocol for imaging and quantification of in situ labeled senescent NSCs

Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.

Identification and prevention of heterotopias in mouse neocortical neural cell migration incurred by surgical damages during utero electroporation procedures

In utero electroporation (IUE) is a useful technique for gene delivery in embryonic mouse brain. IUE technique is used to investigate the mammalian brain development in vivo. However, according to recent studies, IUE methodology has some limitations like the formation of artificial ectopias and heterotopias at the micro-injection site. Thus far, the artificial heterotopias generated by physical trauma during IUE are rarely reported. Here, we reported the artificial heterotopias and ectopias generated from surgical damages of micropipette in detail, and moreover, we described the protocol to avoid these phenotypes. For the experimental purpose, we transferred empty plasmids (pCAGIG-GFP) with green fluorescent-labelled protein into the cortical cortex by IUE and then compared the structure of the cortex region between the injected and un-injected cerebral hemispheres. The coronary section showed that ectopias and heterotopias were appeared on imperfect-injected brains, and layer maker staining, which including Ctip2 and TBR1 and laminin, can differentiate the physical damage, revealing the neurons in artificial ectopic and heterotopic area were not properly arranged. Moreover, premature differentiation of neurons in ectopias and heterotopias were observed. To avoid heterotopias and ectopias, we carefully manipulated the method of IUE application. Thus, this study might be helpful for the in utero electroporator to distinguish the artificial ectopias and heterotopias that caused by the physical injury by microneedle and the ways to avoid those undesirable circumstances.

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.

Functional Analysis of MicroRNAs in Neurogenesis During Mouse Cortical Development

The advantage of using in utero electroporation is that it can study the gene function during neurodevelopment in vivo. Using functional analysis of a microRNA (miRNA) gene as an example, this protocol describes a set of techniques that are crucial for the success of neurogenesis studies, including mice time mating, plasmid preparation, utero electroporation following miRNA injection into mice embryonic brain ventricle, labeling of proliferating cells with EDU (ethynyldeoxyuridine), cryosectioning, immunofluorescence staining, and confocal microscopic analysis. This chapter also provides detailed technical tips regarding experimental planning, mouse surgery, multi-embryo injection with different plasmids, electroporation, and maintenance of pregnant mother with post-electroporated embryo.