scholarly journals Quantitative MRI-Based Analysis Identifies Developmental Limbic Abnormalities in PCDH19 Encephalopathy

2020 ◽  
Vol 30 (11) ◽  
pp. 6039-6050 ◽  
Author(s):  
Matteo Lenge ◽  
Carla Marini ◽  
Edoardo Canale ◽  
Antonio Napolitano ◽  
Salvatore De Masi ◽  
...  
Keyword(s):  
White Matter ◽  
Gene Mutations ◽  
Quantitative Mri ◽  
Cortical Folding ◽  
Limbic Structures ◽  
Developmental Abnormalities ◽  
Calcium Dependent ◽  
Dependent Cell ◽  
Gyrification Index ◽  
Circuit Formation

Abstract Protocadherin-19 (PCDH19) is a calcium dependent cell-adhesion molecule involved in neuronal circuit formation with prevalent expression in the limbic structures. PCDH19-gene mutations cause a developmental encephalopathy with prominent infantile onset focal seizures, variably associated with intellectual disability and autistic features. Diagnostic neuroimaging is usually unrevealing. We used quantitative MRI to investigate the cortex and white matter in a group of 20 PCDH19-mutated patients. By a statistical comparison between quantitative features in PCDH19 brains and in a group of age and sex matched controls, we found that patients exhibited bilateral reductions of local gyrification index (lGI) in limbic cortical areas, including the parahippocampal and entorhinal cortex and the fusiform and lingual gyri, and altered diffusivity features in the underlying white matter. In patients with an earlier onset of seizures, worse psychiatric manifestations and cognitive impairment, reductions of lGI and diffusivity abnormalities in the limbic areas were more pronounced. Developmental abnormalities involving the limbic structures likely represent a measurable anatomic counterpart of the reduced contribution of the PCDH19 protein to local cortical folding and white matter organization and are functionally reflected in the phenotypic features involving cognitive and communicative skills as well as local epileptogenesis.

scholarly journals The cGMP Pathway and Inherited Photoreceptor Degeneration: Targets, Compounds, and Biomarkers

Genes ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 453 ◽  
Author(s):  
Arianna Tolone ◽  
Soumaya Belhadj ◽  
Andreas Rentsch ◽  
Frank Schwede ◽  
François Paquet-Durand
Keyword(s):  
Cell Death ◽  
Gene Mutations ◽  
Interdisciplinary Cooperation ◽  
Response To Treatment ◽  
Common Denominator ◽  
Photoreceptor Degeneration ◽  
Diverse Range ◽  
Cell Death Pathway ◽  
Cgmp Signaling ◽  
Dependent Cell

Photoreceptor physiology and pathophysiology is intricately linked to guanosine-3’,5’-cyclic monophosphate (cGMP)-signaling. Here, we discuss the importance of cGMP-signaling for the pathogenesis of hereditary retinal degeneration. Excessive accumulation of cGMP in photoreceptors is a common denominator in cell death caused by a variety of different gene mutations. The cGMP-dependent cell death pathway may be targeted for the treatment of inherited photoreceptor degeneration, using specifically designed and formulated inhibitory cGMP analogues. Moreover, cGMP-signaling and its down-stream targets may be exploited for the development of novel biomarkers that could facilitate monitoring of disease progression and reveal the response to treatment in future clinical trials. We then briefly present the importance of appropriate formulations for delivery to the retina, both for drug and biomarker applications. Finally, the review touches on important aspects of future clinical translation, highlighting the need for interdisciplinary cooperation of researchers from a diverse range of fields.

Structural features and functional domains of amassin-1, a cell-binding olfactomedin protein

2007 ◽  
Vol 85 (5) ◽  
pp. 552-562 ◽  
Author(s):  
Brian J. Hillier ◽  
Victor D. Vacquier
Keyword(s):  
Disulfide Bonds ◽  
Biological Activities ◽  
Structural Features ◽  
Body Cavity ◽  
Binding Activity ◽  
Coiled Coils ◽  
Cell Binding ◽  
Calcium Dependent ◽  
Dependent Cell ◽  
A Cell

Amassin-1 mediates a rapid cell adhesion that tightly adheres sea urchin coelomocytes (body cavity immunocytes) together. Three major structural regions exist in amassin-1: a short β region, 3 coiled coils, and an olfactomedin domain. Amassin-1 contains 8 disulfide-bonded cysteines that, upon reduction, render it inactive. Truncated forms of recombinant amassin-1 were expressed and purified from Pichia pastoris and their disulfide bonding and biological activities investigated. Expressed alone, the olfactomedin domain contained 2 intramolecular disulfide bonds, existed in a monomeric state, and inhibited amassin-1-mediated clotting of coelomocytes by a calcium-dependent cell-binding activity. The N-terminal β region, containing 3 cysteines, was not required for clotting activity. The coiled coils may dimerize amassin-1 in a parallel orientation through a homodimerizing disulfide bond. Neither amassin-1 fragments that were disulfide-linked as dimers or that were engineered to exist as dimers induced coelomocytes clotting. Clotting required higher multimeric states of amassin-1, possibly tetramers, which occurred through the N-terminal β region and (or) the first segment of coiled coils.

scholarly journals Microstructural properties of the vertical occipital fasciculus explain the variability in human stereoacuity

2018 ◽  
Vol 115 (48) ◽  
pp. 12289-12294 ◽  
Author(s):  
Hiroki Oishi ◽  
Hiromasa Takemura ◽  
Shuntaro C. Aoki ◽  
Ichiro Fujita ◽  
Kaoru Amano
Keyword(s):  
White Matter ◽  
Discrimination Performance ◽  
Quantitative Mri ◽  
Psychophysical Experiment ◽  
Microstructural Properties ◽  
White Matter Tracts ◽  
Depth Discrimination ◽  
Visual Areas ◽  
Highly Correlated ◽  
The Right

Stereopsis is a fundamental visual function that has been studied extensively. However, it is not clear why depth discrimination (stereoacuity) varies more significantly among people than other modalities. Previous studies have reported the involvement of both dorsal and ventral visual areas in stereopsis, implying that not only neural computations in cortical areas but also the anatomical properties of white matter tracts connecting those areas can impact stereopsis. Here, we studied how human stereoacuity relates to white matter properties by combining psychophysics, diffusion MRI (dMRI), and quantitative MRI (qMRI). We performed a psychophysical experiment to measure stereoacuity and, in the same participants, we analyzed the microstructural properties of visual white matter tracts on the basis of two independent measurements, dMRI (fractional anisotropy, FA) and qMRI (macromolecular tissue volume; MTV). Microstructural properties along the right vertical occipital fasciculus (VOF), a major tract connecting dorsal and ventral visual areas, were highly correlated with measures of stereoacuity. This result was consistent for both FA and MTV, suggesting that the behavioral–structural relationship reflects differences in neural tissue density, rather than differences in the morphological configuration of fibers. fMRI confirmed that binocular disparity stimuli activated the dorsal and ventral visual regions near VOF endpoints. No other occipital tracts explained the variance in stereoacuity. In addition, the VOF properties were not associated with differences in performance on a different psychophysical task (contrast detection). These series of experiments suggest that stereoscopic depth discrimination performance is, at least in part, constrained by dorso-ventral communication through the VOF.

Stereological estimation of gyrification index and related measures of cortical folding from MR data in schizophrenia

1997 ◽  
Vol 24 (1-2) ◽  
pp. 157 ◽  
Author(s):  
Martin D. Stefan ◽  
Tonmoy Sharma ◽  
Zoe Ellison ◽  
Robin Murray ◽  
Ian Everall
Keyword(s):  
Cortical Folding ◽  
Gyrification Index

scholarly journals CSF1R-related leukoencephalopathy

Neurology ◽  
2018 ◽  
Vol 91 (24) ◽  
pp. 1092-1104 ◽  
Author(s):  
Takuya Konno ◽  
Koji Kasanuki ◽  
Takeshi Ikeuchi ◽  
Dennis W. Dickson ◽  
Zbigniew K. Wszolek
Keyword(s):  
White Matter ◽  
Cultured Cells ◽  
Clinical Symptoms ◽  
Current Knowledge ◽  
Gene Mutations ◽  
Future Research ◽  
Primary Role ◽  
Extrapyramidal Signs ◽  
Underlying Mechanisms

Since the discovery of CSF1R gene mutations in families with hereditary diffuse leukoencephalopathy with spheroids in 2012, more than 70 different mutations have been identified around the world. Through the analyses of mutation carriers, CSF1R-related leukoencephalopathy has been distinctly characterized clinically, radiologically, and pathologically. Typically, patients present with frontotemporal dementia-like phenotype in their 40s–50s, accompanied by motor symptoms, including pyramidal and extrapyramidal signs. Women tend to develop the clinical symptoms at a younger age than men. On brain imaging, in addition to white matter abnormalities, thinning of the corpus callosum, diffusion-restricted lesions in the white matter, and brain calcifications are hallmarks. Primary axonopathy followed by demyelination was suggested by pathology. Haploinsufficiency of colony-stimulating factor-1 receptor (CSF1R) is evident in a patient with a frameshift mutation, facilitating the establishment of Csf1r haploinsufficient mouse model. These mice develop clinical, radiologic, and pathologic phenotypes consistent with those of human patients with CSF1R mutations. In vitro, perturbation of CSF1R signaling is shown in cultured cells expressing mutant CSF1R. However, the underlying mechanisms by which CSF1R mutations selectively lead to white matter degeneration remains to be elucidated. Given that CSF1R mainly expresses in microglia, CSF1R-related leukoencephalopathy is representative of primary microgliopathies, of which microglia have a pivotal and primary role in pathogenesis. In this review, we address the current knowledge of CSF1R-related leukoencephalopathy and discuss the putative pathophysiology, with a focus on microglia, as well as future research directions.

scholarly journals Desmosomal glycoproteins 2 and 3 (desmocollins) show N-terminal similarity to calcium-dependent cell-cell adhesion molecules

1990 ◽  
Vol 97 (2) ◽  
pp. 239-246
Author(s):  
J.L. Holton ◽  
T.P. Kenny ◽  
P.K. Legan ◽  
J.E. Collins ◽  
J.N. Keen ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Cell Adhesion ◽  
Intercellular Space ◽  
Solid Phase ◽  
Rabbit Antiserum ◽  
High Titre ◽  
Polyclonal Antiserum ◽  
Keyhole Limpet Haemocyanin ◽  
Calcium Dependent ◽  
Dependent Cell

The N-terminal sequence of a mixture of desmosomal glycoproteins 2 and 3 (dg2/3, desmocollins) from bovine nasal epidermis, prepared by electro-elution from polyacrylamide gels, was determined by solid-phase Edman degradation. A sequence of 23 amino acids was obtained. This showed 43% identity with that of the N terminus of the calcium-dependent cell adhesion molecule, N-cadherin. A lesser degree of identity with other members of the cadherin-uvomorulin-L-CAM family was also found. In order to confirm that the sequence was derived from the dg2/3 molecules a rabbit antiserum was raised against a synthetic peptide corresponding to the sequence, conjugated to keyhole limpet haemocyanin (KLH). The antiserum obtained showed high (titre) activity against both the peptide and KLH in ELISA. Each activity could be specifically adsorbed with the appropriate ligand. The antiserum reacted specifically with both dg2 and dg3 of bovine nasal epidermis on immunoblots, this binding was blocked by the N-terminal peptide but was unaffected by KLH. The identity of dg2 and -3 in these preparations was confirmed by immunoblotting with two monoclonal antibodies and one polyclonal antiserum raised against the whole molecules. The N-terminal peptide antiserum was shown to bind to the intercellular space of desmosome profiles by immunoelectron microscopy on ultra-thin frozen sections. One of the two monoclonal antibodies (07–4D) also reacted with the desmosomal intercellular space. dg2 and -3 were shown by Staphylococcus aureus V8 protease digestion to have identical one-dimensional peptide maps. Both the N-terminal antiserum and 07–4D reacted with a V8 fragment of 19,000 Mr derived from dg2 and dg3.(ABSTRACT TRUNCATED AT 250 WORDS)

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