Elsevier

Experimental Neurology

Volume 271, September 2015, Pages 423-431
Experimental Neurology

Research Paper
Cellular and molecular mechanisms of the restoration of human APP transgenic mouse cognitive dysfunction after transplant of human iPS cell-derived neural cells

https://doi.org/10.1016/j.expneurol.2015.07.008Get rights and content

Highlights

  • hiPS cell derived neurons expressed choline acetyltransferase and GABA transporter (82).

  • The neuron transplantation improved cognitive dysfunction of dementia model mice (81).

  • Human Cholinergic neurons located in the cortex with the receptor positive cells (82)

  • Human GABAergic neurons remained in the hippocampus and partly located in the cortex (85).

  • The human grafts may reduce both cholinergic and GABAergic dysfunction of the model (84).

Abstract

Cholinergic neuronal loss is a common finding in patients with Alzheimer's disease (AD) and AD model mice. We previously transplanted neurons derived from human induced pluripotent stem (iPS) cells into the hippocampus of human amyloid precursor protein transgenic AD model mice. In the present study, we examined the cellular and molecular mechanisms involved in the alleviation of cognitive dysfunction in transplanted mice.

After transplant, mice showed improvement in cognitive function, confirming our previous findings. Human choline acetyltransferase (ChAT)-positive cholinergic neurons were distributed throughout the cortex of the grafted mice. Human and mouse ChAT-positive neurons and alpha7 nicotinic acetylcholine receptor (α7nAChR)-positive neurons were significantly increased in the cortex and hippocampus of the grafted mice compared with the vehicle-injected mice. In addition, human and mouse vesicular GABA transporter (VGAT)-positive neurons were located mainly in the hippocampus and, though the number was small, human VGAT-positive neurons were observed in the cortex. In the grafted mouse cortex, the number of GABA receptor (GABAR)-positive neurons of both human origin and mouse origin were significantly increased compared with those in the vehicle-injected mouse cortex. The α7nAChR-positive and GABAR-positive neurons expressed phosphorylated Akt and c-fos in the cortex, suggesting that these receptor-expressing neurons were possibly activated by the neurotransmitters secreted from the grafted neurons.

Collectively, the grafted and host neurons may form positive feedback loops via neurotransmitter secretion in both the cerebral cortex and hippocampus, leading to alleviation of cognitive dysfunction in dementia model mice.

Introduction

Cholinergic neurons and acetylcholine play important roles in learning and memory functions. Cholinergic neuron activity and acetylcholine production are downregulated in patients with Alzheimer's disease (AD) (Davis et al., 1999), and downregulation of alpha7 nicotinic acetylcholine receptors (α7nAChRs) has been reported as one of the hallmarks of AD (Court et al., 2001). Immunohistochemical studies demonstrated that GABAergic neuronal deficits were more severe in AD patients than previously estimated (Schwab et al., 2013). Furthermore, the expressions of several subunits of GABAA receptor (GABAR) were shown to be frequently altered in AD (Rissman and Mobley, 2011).

It has been shown that cell transplantation improved learning and memory function in AD models (Babaei et al., 2012, Bissonnette et al., 2011, Blurton-Jones et al., 2009, Ma et al., 2013, Wang et al., 2006). We have previously reported that transplantation of human induced pluripotent stem (hiPS) cell-derived neurons improved cognitive deficits of PDGF promoter-driven amyloid precursor protein (PDAPP) transgenic dementia model mice (Fujiwara et al., 2013). Choline acetyltransferase (ChAT)-positive cholinergic neurons derived from hiPS cells were shown to be able to survive in the PDAPP mouse hippocampus (Fujiwara et al., 2013).

Here, we transplanted hiPS cell-derived neurons into the hippocampus of PDAPP mice. Cognitive function of the mouse improved significantly by transplantation, confirming our previous finding. After transplantation, we investigated the localization of ChAT, vesicular GABA transporter (VGAT), α7nAChR, and GABAR-expressing cells as well as the activation status of their associated pathways in the brain of dementia model mice.

Section snippets

Cell culture and neural differentiation

The hiPS cell lines, 201B7 and 253G1 (Nakagawa et al., 2008), were provided by RIKEN BRC through the National Bio-Resource Project of the MEXT, Japan, and were used in this study. Because both cell lines demonstrated essentially the same results in this study, only the results obtained using 253G1 (reprogrammed by Oct3/4, Sox2, and Klf4) were presented. The hiPS cell lines were maintained according to the RIKEN cell preparation manual. Cells were cultured in differentiation medium consisting of

Induction of hiPS cell differentiation into cholinergic and GABAergic neurons

Neural cells derived from hiPS cells and control hiPS cells at day 5 (before the addition of RA, NOG and SHH) were stained simultaneously (Fig. 1A). Cells at days 8 (1 day after the second addition of RA, NOG, and SHH) expressed several neural markers, such as nestin (a neural stem/progenitor cell marker), βIII-tubulin (panneuron marker), ChAT (cholinergic neurons), and VGAT (GABAergic neurons). The cells expressed nestin by day 8 (93.6 ± 1.0%: mean ± s.e.m. from three independent experiments, Fig.

Discussion

In the present study we observed that human iPS cell-derived neural cells grafted to dementia model mice differentiated into both ChAT-positive cholinergic neurons and VGAT-positive GABAergic neurons in the cortex and hippocampus. The recipient neurons expressing receptors for the neurotransmitters emerged after transplantation. It is possible that both acetyl choline/α7nAChR interaction and GABA/GABAR interaction in both the cortex and hippocampus may have led to the alleviation of cognitive

Conclusion

The grafted human cells differentiated into both ChAT-positive cholinergic neurons and VGAT-positive GABAergic neurons in the cortex and hippocampus. Recipient neurons expressing receptors for the neurotransmitters emerged after transplantation. The restoration of both acetyl choline/α7nAChR interaction and GABA/GABAR interaction in both the cortex and hippocampus may have led to the alleviation of cognitive dysfunction in the dementia model mice.

Acknowledgments

This study was supported in part by a SRF grant and JSPS KAKENHI Grant Number 25505006. The authors declare no competing financial interest.

References (35)

  • P. Babaei et al.

    Transplanted bone marrow mesenchymal stem cells improve memory in rat models of Alzheimer's disease

    Stem Cells Int.

    (2012)
  • K.R. Bales et al.

    Cholinergic dysfunction in a mouse model of Alzheimer disease is reversed by an anti-A beta antibody

    J. Clin. Invest.

    (2006)
  • C.J. Bissonnette et al.

    The controlled generation of functional basal forebrain cholinergic neurons from human embryonic stem cells

    Stem Cells

    (2011)
  • M. Blurton-Jones et al.

    Neural stem cells improve cognition via BDNF in a transgenic model of Alzheimer disease

    Proc. Natl. Acad. Sci. U. S. A.

    (2009)
  • G. Chen et al.

    A learning deficit related to age and beta-amyloid plaques in a mouse model of Alzheimer's disease

    Nature

    (2000)
  • F. Crestani et al.

    Trace fear conditioning involves hippocampal alpha5 GABA(A) receptors

    Proc. Natl. Acad. Sci. U. S. A.

    (2002)
  • K.L. Davis et al.

    Cholinergic markers in elderly patients with early signs of Alzheimer disease

    JAMA

    (1999)
  • Cited by (19)

    • Defective Reelin/Dab1 signaling pathways associated with disturbed hippocampus development of homozygous yotari mice

      2021, Molecular and Cellular Neuroscience
      Citation Excerpt :

      The cryostat sections were stored at 4 °C until hematoxylin and eosin (HE) and immunofluorescence staining were performed. Immunofluorescence staining was performed as previously described (Arimitsu et al., 2019; Fujiwara et al., 2015). To be brief, sections in 24-well plates were washed and then blocked with 5% goat serum-containing PBS 0.3% Tween/PBS (Jackson Immuno Research, PA).

    • Stem cell therapy in Alzheimer’s disease

      2021, Recent Advances in iPSCs for Therapy, Volume 3: A Volume in Advances in Stem Cell Biology
    • Immunomodulatory effects of stem cells: Therapeutic option for neurodegenerative disorders

      2017, Biomedicine and Pharmacotherapy
      Citation Excerpt :

      Induced PSCs could erase the epigenetic memories [94], which could be useful in diseases that are influenced by environmental factors in an epigenetic way. Neurons derived from human iPSCs restored cognitive dysfunctions once transplanted into the hippocampus of a transgenic AD mouse model [95]. iPSCs derived precursor cells can modulate the autoimmune response in the central nervous system and promote endogenous remyelination and repair process in animal models [6,96,97].

    • The potential of induced pluripotent stem cell derived hepatocytes

      2016, Journal of Hepatology
      Citation Excerpt :

      An added benefit would be the capacity of the cells to respond to potential therapeutic agents. To date a number of diseases have been successfully modelled, including Alzheimer’s disease and amyotrophic lateral sclerosis [74–78]. More specifically regarding liver diseases, models for α1-Antitrypsin (A1AT) deficiency, Wilson’s disease (WD), familial hypercholesterolemia (FH), glycogen storage disease type 1a (GSD1a) familial transthyretin amyloidosis (FTA) and Niemann-Pick type C (NPC) disease have been generated.

    View all citing articles on Scopus
    View full text