Epidemiological studies show that women have a higher prevalence of Alzheimer's disease (AD) than men. Peripheral estrogen reduction during aging in women is proposed to play a key role in this ...sex-associated prevalence, however, the underlying mechanism remains elusive. We previously found that transcription factor early growth response-1 (EGR1) significantly regulates cholinergic function. EGR1 stimulates acetylcholinesterase (AChE) gene expression and is involved in AD pathogenesis. We aimed to investigate whether the triple-transgenic AD (3xTg-AD) mice harboring PS1
, APP
, and Tau
show sex differences in β-amyloid (Aβ) and hyperphosphorylated tau (p-Tau), the two primary AD hallmarks, and how local 17β-estradiol (E2) may regulate the expression of EGR1 and AChE.
We first sacrificed male and female 3xTg-AD mice at 3-4, 7-8, and 11-12 months and measured the levels of Aβ, p-Tau, EGR1, and AChE in the hippocampal complex. Second, we infected SH-SY5Y cells with lentivirus containing the amyloid precursor protein construct C99, cultured with or without E2 administration we measured the levels of extracellular Aβ and intracellular EGR1 and AChE.
Female 3xTg-AD mice had higher levels of Aβ compared to males, while no p-Tau was found in either group. In SH-SY5Y cells infected with lentivirus containing the amyloid precursor protein construct C99, we observed significantly increased extracellular Aβ and decreased expression of intracellular EGR1 and AChE. By adding E2 to the culture medium, extracellular Aβ(l-42) was significantly decreased while intracellular EGR1 and AChE expression were elevated.
This data shows that the 3xTg-AD mouse model can be useful for studying the human sex differences of AD, but only in regards to Ap. Furthermore, in vitro data shows local E2 may be protective for EGR1 and cholinergic functions in AD while suppressing soluble Aβ(1-42) levels. Altogether, this study provides further in vivo and in vitro data supporting the human epidemiological data indicating a higher prevalence of AD in women is related to changes in brain estrogen levels.
Leukodystrophies are often devastating diseases, presented with progressive clinical signs as spasticity, ataxia and cognitive decline, and lack proper treatment options. New therapy strategies for ...leukodystrophies mostly focus on oligodendrocyte replacement to rescue lack of myelin in the brain, even though disease pathology also often involves other glial cells and the spinal cord. In this study we investigated spinal cord pathology in a mouse model for Vanishing White Matter disease (VWM) and show that astrocytes in the white matter are severely affected. Astrocyte pathology starts postnatally in the sensory tracts, followed by changes in the astrocytic populations in the motor tracts. Studies in post‐mortem tissue of two VWM patients, a 13‐year‐old boy and a 6‐year‐old girl, confirmed astrocyte abnormalities in the spinal cord. For proper development of new treatment options for VWM and, possibly, other leukodystrophies, future studies should investigate spinal cord involvement.
Main Points
White matter astrocytes in the Vanishing White Matter spinal cord are severely affected and should also be considered as a therapeutic target.
Introduction
Vanishing white matter (VWM) is a leukodystrophy that leads to neurological dysfunction and early death. Astrocytes are indicated as therapeutic target, because of their central role in ...VWM pathology. Previous cell replacement therapy using primary mouse glial precursors phenotypically improved VWM mice.
Aims
The aim of this study was to determine the translational potential of human stem cell‐derived glial cell replacement therapy for VWM. We generated various glial cell types from human pluripotent stem cells in order to identify a human cell population that successfully ameliorates disease hallmarks of a VWM mouse model. The effects of cell grafts on motor skills and VWM brain pathology were assessed.
Results
Transplantation of human glial precursor populations improved the VWM phenotype. The intrinsic properties of these cells were partially reflected by cell fate post‐transplantation, but were also affected by the host microenvironment. Strikingly, the spread of transplanted cells into the white matter versus the gray matter was different when grafted into the VWM brain as compared to a healthy brain.
Conclusions
Transplantation of human glial cell populations can have therapeutic effects for VWM. For further translation to the clinic, the microenvironment in the VWM patient brain should be considered as an important moderator of cell replacement therapy.
Intracranial transplantation of human stem cell‐derived glial progenitor populations improves the leukodystrophy phenotype of Vanishing white matter (VWM) mice. In the VWM brain, transplanted cells show altered migration and cell fate as compared to cells transplanted into a healthy brain. Translation to the clinic should consider the microenvironment in the VWM brain as an important moderator of cell replacement therapy.
Stem cell therapy has great prospects for brain white matter disorders, including the genetically determined disorders called leukodystrophies. We focus on the devastating leukodystrophy vanishing ...white matter (VWM). Patients with VWM show severe disability and early death, and treatment options are lacking. Previous studies showed successful cell replacement therapy in rodent models for myelin defects. However, proof-of-concept studies of allogeneic cell replacement in models representative of human leukodystrophies are lacking. We tested cell replacement in a mouse model representative of VWM. We transplanted different murine glial progenitor cell populations and showed improved pathological hallmarks and motor function. Improved mice showed a higher percentage of transplanted cells that differentiated into GFAP+ astrocytes, suggesting best therapeutic prospects for replacement of astroglial lineage cells. This is a proof-of-concept study for cell transplantation in VWM and suggests that glial cell replacement therapy is a promising therapeutic strategy for leukodystrophy patients.
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•Cell therapy improved pathology and motor skills in vanishing white matter mice•Astrocyte differentiation of donor cells was associated with recovery of VWM symptoms
Vanishing white matter (VWM) is a severe genetic white matter disorder for which no curative treatment is available. Heine and colleagues show that transplantation with glial progenitor cells can improve pathology and motor skills in VWM mice. Improvement was correlated with increased astrocyte differentiation of donor cells, showing that astrocyte targeting is essential for VWM therapy.
The etiology of hereditary ataxia syndromes is heterogeneous, and the mechanisms underlying these disorders are often unknown. Here, we utilized exome sequencing in two siblings with progressive ...ataxia and muscular weakness and identified a novel homozygous splice mutation (c.3020-1G > A) in neurofascin (
NFASC
). In RNA extracted from fibroblasts, we showed that the mutation resulted in inframe skipping of exon 26, with a deprived expression of the full-length transcript that corresponds to
NFASC
isoform NF186. To further investigate the disease mechanisms, we reprogrammed fibroblasts from one affected sibling to induced pluripotent stem cells, directed them to neuroepithelial stem cells and finally differentiated to neurons. In early neurogenesis, differentiating cells with selective depletion of the NF186 isoform showed significantly reduced neurite outgrowth as well as fewer emerging neurites. Furthermore, whole-cell patch-clamp recordings of patient-derived neuronal cells revealed a lower threshold for openings, indicating altered Na
+
channel kinetics, suggesting a lower threshold for openings as compared to neuronal cells without the
NFASC
mutation. Taken together, our results suggest that loss of the full-length
NFASC
isoform NF186 causes perturbed neurogenesis and impaired neuronal biophysical properties resulting in a novel early-onset autosomal recessive ataxia syndrome.
Abstract
4H leukodystrophy is a rare genetic disorder classically characterized by hypomyelination, hypodontia and hypogonadotropic hypogonadism. With the discovery that 4H is caused by mutations ...that affect RNA polymerase III, mainly involved in the transcription of small non-coding RNAs, patients with atypical presentations with mainly a neuronal phenotype were also identified. Pathomechanisms of 4H brain abnormalities are still unknown and research is hampered by a lack of preclinical models. We aimed to identify cells and pathways that are affected by 4H mutations using induced pluripotent stem cell models.
RNA sequencing analysis on induced pluripotent stem cell-derived cerebellar cells revealed several differentially expressed genes between 4H patients and control samples, including reduced ARX expression. As ARX is involved in early brain and interneuron development, we studied and confirmed interneuron changes in primary tissue of 4H patients. Subsequently, we studied interneuron changes in more depth and analysed induced pluripotent stem cell-derived cortical neuron cultures for changes in neuronal morphology, synaptic balance, network activity and myelination. We showed a decreased percentage of GABAergic synapses in 4H, which correlated to increased neuronal network activity. Treatment of cultures with GABA antagonists led to a significant increase in neuronal network activity in control cells but not in 4H cells, also pointing to lack of inhibitory activity in 4H. Myelination and oligodendrocyte maturation in cultures with 4H neurons was normal, and treatment with sonic hedgehog agonist SAG did not improve 4H related neuronal phenotypes. Quantitative PCR analysis revealed increased expression of parvalbumin interneuron marker ERBB4, suggesting that the development rather than generation of interneurons may be affected in 4H.
Together, these results indicate that interneurons are involved, possibly parvalbumin interneurons, in disease mechanisms of 4H leukodystrophy.
4H leukodystrophy is a rare white matter disorder with unknown pathomechanisms. Using iPSC-derived cultures, Dooves et al. reveal reduced expression of ARX, increased neuronal network activity, and altered development of interneurons—particularly parvalbumin lineage—in patients with this disorder.
Abstract
Leukodystrophies are often devastating diseases, presented with progressive clinical signs as spasticity, ataxia and cognitive decline, and lack proper treatment options. New therapy ...strategies for leukodystrophies mostly focus on oligodendrocyte replacement to rescue lack of myelin in the brain, even though disease pathology also often involves other glial cells and the spinal cord. In this study we investigated spinal cord pathology in a mouse model for Vanishing White Matter disease (VWM) and show that astrocytes in the white matter are severely affected. Astrocyte pathology starts postnatally in the sensory tracts, followed by changes in the astrocytic populations in the motor tracts. Studies in post‐mortem tissue of two VWM patients, a 13‐year‐old boy and a 6‐year‐old girl, confirmed astrocyte abnormalities in the spinal cord. For proper development of new treatment options for VWM and, possibly, other leukodystrophies, future studies should investigate spinal cord involvement.
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