Progressive Volume Loss and White Matter Degeneration in Cstb-Deficient Mice: A Diffusion Tensor and Longitudinal Volumetry MRI Study

Manninen, Otto; Laitinen, Tomi; Lehtimäki, Kimmo; Tegelberg, Saara; Lehesjoki, Anna‐Elina; Gröhn, Olli; Kopra, Outi

doi:10.1371/journal.pone.0090709

Cited by 20 publications

(26 citation statements)

References 37 publications

(59 reference statements)

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“…Here we show similar effects in the hippocampus, as young early symptomatic (P30) Cstb KO mice contained fewer hippocampal granule cells and a tendency to atrophy of the septal hippocampus, with no changes at the hippocampal temporal region. In agreement, an age-dependent hippocampal volume 0 loss was reported in Cstb KO mice using in vivo magnetic resonance imaging (MRI) volumetry starting at 2 months of age and peaking at 6 46 . The differences observed in the initiation of hippocampal atrophy may be explained by the higher sensitivity of stereology based cell quantification methods when compared to MRI structural change assessment 47 .…”

Section: Early Symptomatic Cstb Ko Mice Exhibit Slight Atrophy Of Thesupporting

confidence: 69%

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Microglial phagocytosis dysfunction is related to local neuronal activity in a genetic model of epilepsy

Sierra-Torre

Plaza-Zabala

Bonifazi

et al. 2020

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Microglial phagocytosis of apoptotic cells is an essential component of the brain regenerative response in neurodegenerative diseases. Phagocytosis is very efficient in physiological conditions, as well as during apoptotic challenge induced by excitotoxicity or inflammation, but is impaired in mouse and human mesial temporal lobe epilepsy (MTLE). Here we extend our studies to a genetic model of progressive myoclonus epilepsy type 1 (EPM1) in mice lacking cystatin B (CSTB), an inhibitor of cysteine proteases involved in lysosomal proteolysis. We first demonstrated that microglial phagocytosis was impaired in the hippocampus in Cstb knock-out (KO) mice when seizures arise and hippocampal atrophy begins, at 1 month of age. To test if this blockage was related to the lack of Cstb in microglia, we used an in vitro model of phagocytosis and siRNAs to acutely reduce Cstb expression but we found no significant effect in the phagocytosis of apoptotic cells. We then tested whether seizures were involved in the phagocytosis impairment, similar to MTLE, and analyzed Cstb KO mice before seizures begin, at postnatal day 14. Here, phagocytosis impairment was restricted to the granule neuron layer but not to the subgranular zone, where there are no active neurons. Furthermore, we observed apoptotic cells (both phagocytosed and not phagocytosed) in Cstb deficient mice at close proximity to active, cFos + neurons and used mathematical modeling to demonstrate that the physical relationship between apoptotic cells and cFos+ neurons was specific for Cstb KO mice. These results suggest a complex crosstalk between apoptosis, phagocytosis and neuronal activity, hinting that local neuronal activity could be related to phagocytosis dysfunction in Cstb KO mice. Overall, this data suggest that phagocytosis impairment is an early feature of hippocampal damage in epilepsy and opens novel therapeutic approaches for epileptic patients based on targeting microglial phagocytosis. METHODS Mice. Tissues ofCstb KO mice 7 (129S2/SvHsd5-Cstb tm1Rm ; Jackson Laboratory stock no. #003486) were obtained from the Lehesjoki´s lab at Folkhälsan Research Center and University of Helsinki. Wild-type litter mates with the same genetic background were used as controls. For the FACS experiments, fms-EGFP mice (B6.Cg-Tg(Csf1r-EGFP)1Hume/J; Jackson Laboratory stock #018549), where microglia constitutively express the GFP protein 25,26 were used. All procedures followed the European Directive 2010/63/EU and NIH guidelines, and were approved by the Animal Ethics Committee of the State Provincial Office of Southern Finland (decisions ) and Ethics Committees of the University of the Basque Country EHU/ UPV (Leioa, Spain; CEBA/205/2011, CEBA/206/2011, CEIAB/82/2011, CEIAB/105/2012). BV2 cell line. BV2 cells (Interlab Cell Line Collection San Martino-Instituto ScientificoTumori-Instituto Nazionale per la Ricerca sul Cancro), a cell line derived from raf/mycimmortalized rat neonatal microglia was used to perform the in vitro knock-down model of Cstb. BV2 cells were grown...

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Section: Early Symptomatic Cstb Ko Mice Exhibit Slight Atrophy Of Thesupporting

confidence: 69%

“…Progressive loss of brain volume that affects different structures has been reported in patients with CSTB mutations 5,6,44,45 as well as in Cstb KO mice 3,10,11,46 . At early disease stages in Cstb KO mice, apoptosis of granule neurons 7 and atrophy 11 are most prevalent in the cerebellum.…”

Section: Early Symptomatic Cstb Ko Mice Exhibit Slight Atrophy Of Thementioning

confidence: 96%

Microglial phagocytosis dysfunction is related to local neuronal activity in a genetic model of epilepsy

Sierra-Torre

Plaza-Zabala

Bonifazi

et al. 2020

Preprint

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“…In one study, higher VBA sensitivity over TBSS was demonstrated following improved registration. 14 In rodents, the use of TBSS to analyze DTI data [15][16][17][18][19][20][21][22] has been generally inconsistent and suboptimal with regard to the parametrization: the FA threshold, separating WM from gray matter, varies between the studies and the normalization strategy is often limited to the most representative subject (MRS). Moreover, no study has assessed the impact of the projection.…”

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confidence: 99%

User‐independent diffusion tensor imaging analysis pipelines in a rat model presenting ventriculomegalia: A comparison study

et al. 2017

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Automated analysis of diffusion tensor imaging (DTI) data is an appealing way to process large datasets in an unbiased manner. However, automation can sometimes be linked to a lack of interpretability. Two whole-brain, automated and voxelwise methods exist: voxel-based analysis (VBA) and tract-based spatial statistics (TBSS). In VBA, the amount of smoothing has been shown to influence the results. TBSS is free of this step, but a projection procedure is introduced to correct for residual misalignments. This projection assigns the local highest fractional anisotropy (FA) value to the mean FA skeleton, which represents white matter tract centers. For both methods, the normalization procedure has a major impact. These issues are well documented in humans but, to our knowledge, not in rodents. In this study, we assessed the quality of three different registration algorithms (ANTs SyN, DTI-TK and FNIRT) using study-specific templates and their impact on automated analysis methods (VBA and TBSS) in a rat pup model of diffuse white matter injury presenting large unilateral deformations. VBA and TBSS results were stable and anatomically coherent across the three pipelines. For VBA, in regions around the large deformations, interpretability was limited because of the increased partial volume effect. With TBSS, two of the three pipelines found a significant decrease in axial diffusivity (AD) at the known injury site. These results demonstrate that automated voxelwise analyses can be used in an animal model with large deformations.

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“…The mouse model recapitulates the principal symptoms of EPM1, myoclonic seizures and progressive ataxia (Pennacchio et al, 1998). Pathological findings in Cstb −/− mice match those in the patients: the mice exhibit progressive loss in brain volume due to neuronal death and consequent white matter atrophy in the cerebrum and cerebellum (Tegelberg et al, 2012, Manninen et al, 2013, Manninen et al, 2014). The earliest pathological finding in Cstb −/− mice is striking microglial activation present at postnatal day 14 and preceding the onset of myoclonus and progressive neuronal degeneration from 1 month of age onwards (Tegelberg et al, 2012).…”

Section: Introductionmentioning

confidence: 57%

Impaired osteoclast homeostasis in the cystatin B-deficient mouse model of progressive myoclonus epilepsy

et al. 2015

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Progressive myoclonus epilepsy of Unverricht–Lundborg type (EPM1) is an autosomal recessively inherited disorder characterized by incapacitating stimulus-sensitive myoclonus and tonic-clonic epileptic seizures with onset at the age of 6 to 16 years. EPM1 patients also exhibit a range of skeletal changes, e.g., thickened frontal cranial bone, arachnodactyly and scoliosis. Mutations in the gene encoding cystatin B (CSTB) underlie EPM1. CSTB is an inhibitor of cysteine cathepsins, including cathepsin K, a key enzyme in bone resorption by osteoclasts. CSTB has previously been shown to protect osteoclasts from experimentally induced apoptosis and to modulate bone resorption in vitro. Nevertheless, its physiological function in bone and the cause of the bone changes in patients remain unknown. Here we used the CSTB-deficient mouse (Cstb−/−) model of EPM1 to evaluate the contribution of defective CSTB protein function on bone pathology and osteoclast differentiation and function. Micro-computed tomography of hind limbs revealed thicker trabeculae and elevated bone mineral density in the trabecular bone of Cstb−/− mice. Histology from Cstb−/− mouse bones showed lower osteoclast count and thinner growth plates in long bones. Bone marrow-derived osteoclast cultures revealed lower osteoclast number and size in the Cstb−/− group. Cstb−/− osteoclasts formed less and smaller resorption pits in an in vitro assay. This impaired resorptive capacity was likely due to a decrease in osteoclast numbers and size. These data imply that the skeletal changes in Cstb−/− mice and in EPM1 patients are a result of CSTB deficiency leading to impaired osteoclast formation and consequently compromised resorptive capacity. These results suggest that the role of CSTB in osteoclast homeostasis and modulation of bone metabolism extends beyond cathepsin K regulation.

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Progressive Volume Loss and White Matter Degeneration in Cstb-Deficient Mice: A Diffusion Tensor and Longitudinal Volumetry MRI Study

Cited by 20 publications

References 37 publications

Microglial phagocytosis dysfunction is related to local neuronal activity in a genetic model of epilepsy

Microglial phagocytosis dysfunction is related to local neuronal activity in a genetic model of epilepsy

User‐independent diffusion tensor imaging analysis pipelines in a rat model presenting ventriculomegalia: A comparison study

Impaired osteoclast homeostasis in the cystatin B-deficient mouse model of progressive myoclonus epilepsy

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