Ultrastructural Abnormalities in Induced Pluripotent Stem Cell-Derived Neural Stem Cells and Neurons of Two Cohen Syndrome Patients.

Cohen syndrome is an autosomal recessive disorder caused by VPS13B (COH1) gene mutations. This syndrome is significantly underdiagnosed and is characterized by intellectual disability, microcephaly, autistic symptoms, hypotension, myopia, retinal dystrophy, neutropenia, and obesity. VPS13B regulates intracellular membrane transport and supports the Golgi apparatus structure, which is critical for neuron formation. We generated induced pluripotent stem cells from two patients with pronounced manifestations of Cohen syndrome and differentiated them into neural stem cells and neurons. Using transmission electron microscopy, we documented multiple new ultrastructural changes associated with Cohen syndrome in the neuronal cells. We discovered considerable disturbances in the structure of some organelles: Golgi apparatus fragmentation and swelling, endoplasmic reticulum structural reorganization, mitochondrial defects, and the accumulation of large autophagosomes with undigested contents. These abnormalities underline the ultrastructural similarity of Cohen syndrome to many neurodegenerative diseases. The cell models that we developed based on patient-specific induced pluripotent stem cells can serve to uncover not only neurodegenerative processes, but the causes of intellectual disability in general.

[The differential diagnosis of constitutional delay of puberty and hypogonadotropic hypogonadism in boys].

BACKGROUND: The problem of differential diagnosis of constitutional delay of puberty/CDP and hypogonadotropic hypogonadism/HH in boys is discussed, as boys have similar genetic mechanisms and appearance. AIMS: to determine accuracy of the criteria for the differential diagnosis of CDP and HH. MATERIALS: The study included 56 boys 14.4±0.7 years old with delayed puberty (G1P1-3/testicular volume <3 сm3). We excluded patients with hypergonadotropic hypogonadism, treated with sex steroids or gonadotropins for 12 months, with endocrine/somatic diseases affecting puberty. At the first visit, we evaluated anthropometric data, bone age, testicular volume, hormones and the results of the gonadotropin-releasing hormone test (GnRH) agonist test and the human chorionic gonadotropin test (hCG) test. The HH was defined by a testicular volume <3 сm3 after 2 years follow-up. The patients were divided into two groups: the first group with CDP and testicles ≥3 cm3 (n=50) and the second group with HH and testicles <3 cm3 (n=6). RESULTS: At the first visit in boys with CDP corrected target height was less (Me SDS –1.8 vs –0,4, р=0.02), bone age was less (Ме SDS –2.5 vs –0.2 р=0.03), testicular volume was more (Ме 1.9 vs 0.5, p=0.0003), hormones were significantly higher, such as LH (Ме 1.1 vs 0.1 mIU/ml, p=0.0002), FSH (Ме 1.9 vs 0.2 IU/l, p=0.00007), inhibin B (Ме 142.3 vs 31.3 pg/ml, p=0.00009), max LH (Ме 18.9 vs 0.6 mIU/ml, p=0.00007), max LH/FSH (Ме 2.3 vs 0.4, p=0.0002) on the GnRH agonist test and Δ testosterone (Ме 14.4 vs 1.1 nmol/l, p=0.0001) on the hCG test than in boys with HH. The LH ≥0.3 mIU/ml had 86% sensitivity, 100% specificity; max LH/FSH ≥1 – 92% sensitivity, 100% specificity; Δ testosterone ≥2.7 nmol/l on the hCG test – 98% sensitivity, 100% specificity for differential diagnosis of CDP and HH in boys. However, max LH ≥3.5 mIU/ml on the GnRH agonist test, FSH ≥0.5 IU/l, inhibin B ≥58 pg/ml had 100% sensitivity and specificity for diagnosis of CDP. CONCLUSIONS: The inhibin B ≥58 pg/ml, LH ≥0.3 mIU/ml, FSH ≥0.5 IU/l or max LH ≥3.5 mIU/ml, max LH/FSH ≥1,0 on the GnRH agonist test, Δ testosterone ≥2.7 nmol/l on the hCG test have an excellent accuracy for the differential diagnosis of CDP and HH in prepubertal boys with delayed puberty.

A New Look at Etiological Factors of Idiopathic Scoliosis: Neural Crest Cells.

Idiopathic scoliosis is one of the most common disabling pathologies of children and adolescents. Etiology and pathogenesis of idiopathic scoliosis remain unknown. To study the etiology of this disease we identified the cells' phenotypes in the vertebral body growth plates in patients with idiopathic scoliosis. Materials and methods: The cells were isolated from vertebral body growth plates of the convex and concave sides of the deformity harvested intraoperatively in 50 patients with scoliosis. Cells were cultured and identified by methods of common morphology, neuromorphology, electron microscopy, immunohistochemistry and PCR analysis. Results: Cultured cells of convex side of deformation were identified as chondroblasts. Cells isolated from the growth plates of the concave side of the deformation showed numerous features of neuro- and glioblasts. These cells formed synapses, contain neurofilaments, and expressed neural and glial proteins. Conclusion: For the first time we demonstrated the presence of cells with neural/glial phenotype in the concave side of the vertebral body growth plate in scoliotic deformity. We hypothesized that neural and glial cells observed in the growth plates of the vertebral bodies represent derivatives of neural crest cells deposited in somites due to alterations in their migratory pathway during embryogenesis. We also propose that ectopic localization of cells derived from neural crest in the growth plate of the vertebral bodies is the main etiological factor of the scoliotic disease.

Microporous Materials Based on Norbornadiene-Based Cross-Linked Polymers.

New microporous homopolymers were readily prepared from norbornadiene-2,5, its dimer and trimer by addition (vinyl) polymerization of the corresponding monomers with 60⁻98% yields. As a catalyst Pd-N-heterocyclic carbene complex or Ni(II) 2-ethylhexanoate activated with Na⁺[B(3,5-(CF3)2C6H3)4]- or methylaluminoxane was used. The synthesized polynorbornenes are cross-linked and insoluble. They are glassy and amorphous polymers. Depending on the nature of the catalyst applied, BET surface areas were in the range of 420⁻970 m²/g. The polymers with the highest surface area were obtained in the presence of Pd-catalysts from the trimer of norbornadiene-2,5. The total pore volume of the polymers varies from 0.39 to 0.79 cm³/g, while the true volume of micropores was 0.14⁻0.16 cm³/g according to t-plot. These polymers gave CO2 uptake from 1.2 to 1.9 mmol/g at 273 K and 1 atm. The porous structure of new polymers was also studied by means of wide-angle X-ray diffraction and positron annihilation lifetime spectroscopy.

Combination of cyclophosphamide and double-stranded DNA demonstrates synergistic toxicity against established xenografts.

BACKGROUND: Extracellular double-stranded DNA participates in various processes in an organism. Here we report the suppressive effects of fragmented human double-stranded DNA along or in combination with cyclophosphamide on solid and ascites grafts of mouse Krebs-2 tumor cells and DNA preparation on human breast adenocarcinoma cell line MCF-7. METHODS: Apoptosis and necrosis were assayed by electrophoretic analysis (DNA nucleosomal fragmentation) and by measurements of LDH levels in ascitic fluid, respectively. DNA internalization into MCF-7 was analyzed by flow cytometry and fluorescence microscopy. RESULTS: Direct cytotoxic activity of double-stranded DNA (along or in combination with cyclophosphamide) on a solid transplant was demonstrated. This resulted in delayed solid tumor proliferation and partial tumor lysis due to necrosis of the tumor and adjacent tissues. In the case of ascites form of tumor, extensive apoptosis and secondary necrosis were observed. Similarly, MCF-7 cells showed induction of massive apoptosis (up to 45%) as a result of treatments with double-stranded DNA preparation. CONCLUSIONS: Double-stranded DNA (along or in combination with cyclophosphamide) induces massive apoptosis of Krebs-2 ascite cells and MCF-7 cell line (DNA only). In treated mice it reduces the integrity of gut wall cells and contributes to the development of systemic inflammatory reaction.

Dominance of parental genomes in embryonic stem cell/fibroblast hybrid cells depends on the ploidy of the somatic partner.

Two dozen hybrid clones were produced by fusion of diploid embryonic stem (ES) cells positive for green fluorescent protein (GFP) with tetraploid fibroblasts derived from DD/c and C57BL-I(I)1RK mice. Cytogenetic analysis demonstrated that most cells from these hybrid clones contained near-hexaploid chromosome sets. Additionally, the presence of chromosomes derived from both parental cells was confirmed by polymerase chain reaction (PCR) analysis of polymorphic microsatellites. All hybrid cells were positive for GFP and demonstrated growth characteristics and fibroblast-like morphology. In addition, most hybrid cells were positive for collagen type I, fibronectin, and lamin A/C but were negative for Oct4 and Nanog proteins. Methylation status of the Oct4 and Nanog gene promoters was evaluated by bisulfite genomic sequencing analysis. The methylation sites (CpG-sites) of the Oct4 and Nanog gene promoters were highly methylated in hybrid cells, whereas the CpG-sites were unmethylated in the parental ES cells. Thus, the fibroblast genome dominated the ES genome in the diploid ES cell/tetraploid fibroblast hybrid cells. Immunofluorescent analysis of the pluripotent and fibroblast markers demonstrated that establishment of the fibroblast phenotype occurred shortly after fusion and that the fibroblast phenotype was further maintained in the hybrid cells. Fusion of karyoplasts and cytoplast derived from tetraploid fibroblasts with whole ES cells demonstrated that karyoplasts were able to establish the fibroblast phenotype of the reconstructed cells but not fibroblast cytoplasts. Thus, these data suggest that the dominance of parental genomes in hybrid cells of ES cell/somatic cell type depends on the ploidy of the somatic partner.

Exogenous allogenic fragmented double-stranded DNA is internalized into human dendritic cells and enhances their allostimulatory activity.

Exogenous allogenic DNA as nucleosome-free fragments reaches main cellular compartments (cytoplasm, nucleus) of human dendritic cells and deposits in the nuclear interchromosomal space without visibly changing in linear size. The presence of such allogenic fragmented DNA in medium in which human dendritic cells are cultured produces an enhancement of their allostimulatory activity. This enhancement is comparable to that produced by the standard maturation stimulus lipopolysaccharide Escherichia coli.

Cdk1 and okadaic acid-sensitive phosphatases control assembly of nuclear pore complexes in Drosophila embryos.

Disassembly and reassembly of the nuclear pore complexes (NPCs) is one of the major events during open mitosis in higher eukaryotes. However, how this process is controlled by the mitotic machinery is not clear. To investigate this we developed a novel in vivo model system based on syncytial Drosophila embryos. We microinjected different mitotic effectors into the embryonic cytoplasm and monitored the dynamics of disassembly/reassembly of NPCs in live embryos using fluorescently labeled wheat germ agglutinin (WGA) or in fixed embryos using electron microscopy and immunostaining techniques. We found that in live embryos Cdk1 activity was necessary and sufficient to induce disassembly of NPCs as well as their cytoplasmic mimics: annulate lamellae pore complexes (ALPCs). Cdk1 activity was also required for keeping NPCs and ALPCs disassembled during mitosis. In agreement recombinant Cdk1/cyclin B was able to induce phosphorylation and dissociation of nucleoporins from the NPCs in vitro. Conversely, reassembly of NPCs and ALPCs was dependent on the activity of protein phosphatases, sensitive to okadaic acid (OA). Our findings suggest a model where mitotic disassembly/reassembly of the NPCs is regulated by a dynamic equilibrium of Cdk1 and OA-sensitive phosphatase activities and provide evidence that mitotic phosphorylation mediates disassembly of the NPC.

Annulate lamellae play only a minor role in the storage of excess nucleoporins in Drosophila embryos.

The nuclear pore complexes (NPCs), multiprotein assemblies embedded in the nuclear envelope, conduct nucleo-cytoplasmic traffic of macromolecules. Mimics of NPCs, called annulate lamellae pore complexes (ALPCs), are usually found in cytoplasmic membranous stacks in oocytes and early embryonic cells. They are believed to constitute storage compartments for excess premade nucleoporins. To evaluate the extent to which ALPCs store nucleoporins in early embryonic cells we took advantage of syncytial Drosophila embryos, containing both AL and rapidly proliferating nuclei in the common cytoplasm. Electron microscopic morphometric analysis showed that the number of ALPCs did not decrease to compensate for the growing number of NPCs during syncytial development. We performed Western blot analysis to quantify seven different nucleoporins and analyzed their intraembryonal distribution by confocal microscopy and subcellular fractionation. Syncytial embryos contained a large maternally contributed stockpile of nucleoporins. However, even during interphases, only a small fraction of the excess nucleoporins was assembled into ALPCs, whereas the major fraction was soluble and contained at least one phosphorylated nucleoporin. We conclude that in Drosophila embryos ALPCs play only a minor role in storing the excess maternally contributed nucleoporins. Factors that may prevent nucleoporins from assembly into ALPCs are discussed.