Humans ; Cardiomyopathies/genetics* ; Laminopathies ; Lamin Type A/genetics* ; Mutation

The eukaryotic genome is folded into higher-order conformation accompanied with constrained dynamics for coordinated genome functions. However, the molecular machinery underlying these hierarchically organized three-dimensional (3D) chromatin architecture and dynamics remains poorly understood. Here by combining imaging and sequencing, we studied the role of lamin B1 in chromatin architecture and dynamics. We found that lamin B1 depletion leads to detachment of lamina-associated domains (LADs) from the nuclear periphery accompanied with global chromatin redistribution and decompaction. Consequently, the inter-chromosomal as well as inter-compartment interactions are increased, but the structure of topologically associating domains (TADs) is not affected. Using live-cell genomic loci tracking, we further proved that depletion of lamin B1 leads to increased chromatin dynamics, owing to chromatin decompaction and redistribution toward nucleoplasm. Taken together, our data suggest that lamin B1 and chromatin interactions at the nuclear periphery promote LAD maintenance, chromatin compaction, genomic compartmentalization into chromosome territories and A/B compartments and confine chromatin dynamics, supporting their crucial roles in chromatin higher-order structure and chromatin dynamics.
Chromatin ; Chromosomes ; Genome ; Humans ; Lamin Type B/genetics*

OBJECTIVE: To report on a patient with congenital muscular dystrophy (CMD) due to a missense variant of LMNA gene and explore its pathogenicity. METHODS: The 1-year-and-1-month-old boy has presented with motor development delay and elevation of muscle enzymes for more than half a year. Congenital myopathy was suspected. Following muscle biopsy, HE staining, immunostaining and electron microscopy were conducted to clarify the clinical diagnosis. Meanwhile, DNA was extracted from the child and his parents' peripheral venous blood samples. Trio-whole exome sequencing (trio-WES) was carried out to detect pathogenic variant in the child. Candidate variant was verified by Sanger sequencing and bioinformatic analysis. RESULTS: Both light and electron microscopy showed a large area of necrotic muscle tissues with infiltration of inflammatory cells. Immunohistochemistry revealed a large amount of muscle cells to be diffusely positive for Dysferlin. The patient's motor delays, elevations of muscle enzymes and histopathological results suggested a clinical diagnosis of CMD. A de novo missense c.1072G>A (p.E358K) variant was detected in the LMNA gene by trio-WES. The variant was unreported previously (PS2) and was absent from major allele frequency databases (PM2). It was a loss of function variant and was considered as hotspot variant in the LMNA gene (PM1) as the amino acid (E), located in position 358, was highly conserved, and change of this amino acid was found to cause destruction of the filament domain (AA: 30-386), which may result in serious damage to the intermediate filament protein. Furthermore, c.1072G>A (p. E358K) in LMNA gene was also predicted to be pathogenic based on MutationTaster, PROVEAN and PolyPhen-2 (PP3) analysis. According to the guidelines of the American College of Medical Genetics and Genomics (ACMG), the variant was classified to be likely pathogenic (PS2+PM1+PM2+PP3). CONCLUSION The child's condition may be attributed to the de novo missense c.1072 G>A (p.E358K) variant of the LMNA gene. Above discovery has expanded the variant spectrum of the LMNA gene.
Gene Frequency ; Genomics ; Humans ; Infant ; Lamin Type A/genetics* ; Male ; Muscular Dystrophies/genetics* ; Mutation ; Whole Exome Sequencing

Hutchinson-Gilford progeria syndrome (HGPS) and Werner syndrome (WS) are two of the best characterized human progeroid syndromes. HGPS is caused by a point mutation in lamin A (LMNA) gene, resulting in the production of a truncated protein product-progerin. WS is caused by mutations in WRN gene, encoding a loss-of-function RecQ DNA helicase. Here, by gene editing we created isogenic human embryonic stem cells (ESCs) with heterozygous (G608G/+) or homozygous (G608G/G608G) LMNA mutation and biallelic WRN knockout, for modeling HGPS and WS pathogenesis, respectively. While ESCs and endothelial cells (ECs) did not present any features of premature senescence, HGPS- and WS-mesenchymal stem cells (MSCs) showed aging-associated phenotypes with different kinetics. WS-MSCs had early-onset mild premature aging phenotypes while HGPS-MSCs exhibited late-onset acute premature aging characterisitcs. Taken together, our study compares and contrasts the distinct pathologies underpinning the two premature aging disorders, and provides reliable stem-cell based models to identify new therapeutic strategies for pathological and physiological aging.
Aging ; genetics ; physiology ; DNA Helicases ; genetics ; Human Embryonic Stem Cells ; metabolism ; physiology ; Humans ; Kinetics ; Lamin Type A ; genetics ; Mesenchymal Stem Cells ; metabolism ; physiology ; Mutation ; Progeria ; genetics ; physiopathology ; Werner Syndrome ; genetics ; physiopathology

To investigate the effect ofgene down-regulation on early hematopoietic development of zebrafish.Phosphorodiamidate morpholino oligomer (PMO) technology was used to downregulategene expression in Zebrafish. Zebrafish embryos injected phosphorodiamidate morpholino antisense oligonucleotide ofgene mRNA by microinjection at unicellular stage were taken as the experimental group, and those injected meaningless phosphorodiamidate morpholino antisense oligonucleotide were taken as the control. The embryos were collected at 18, 24, 30 and 36 hpf after the fertilization. The real-time fluorescent quantitative PCR (RT-PCR) and whole embryohybridization methods were used to detect the expression of myeloid hematopoietic transcription factorand erythroid hematopoietic transcription factorin zebrafish.RT-PCR showed that the expressions ofanddecreased in the experimental group compared with the control group (all<0.05). Whole embryohybridization showed that the blue-black positive hybridization signals ofandin experimental group were shallow than those in the control group.Myeloid hematopoietic and erythroid hematopoietic of zebrafish are blocked with the downregulation ofgene.
Animals ; Down-Regulation ; genetics ; Embryo, Nonmammalian ; physiopathology ; GATA1 Transcription Factor ; genetics ; metabolism ; Gene Knockdown Techniques ; Hematopoiesis ; In Situ Hybridization ; Lamin Type A ; genetics ; physiology ; Proto-Oncogene Proteins ; genetics ; metabolism ; Trans-Activators ; genetics ; metabolism ; Zebrafish ; embryology ; genetics

Adolescent ; Adult ; Base Sequence ; Female ; Humans ; Lamin Type A ; genetics ; Molecular Sequence Data ; Muscular Dystrophy, Emery-Dreifuss ; genetics ; Mutation

OBJECTIVETo explore clinical, radiographical and genetic characteristics of classical Hutchinson-Gilford progeria syndrome (HGPS).

METHODData of a case of HGPS diagnosed at Tongji Hospital Affiliated to Tongji Medical College of Huazhong University of Science and Technology was analyzed and related literature was reviewed.

RESULTAt the age of 8 months, the affected-infant presented with characteristic manifestation such as short stature, low weight, frontal bossing, alopecia, prominent scalp veins, micrognathia with a vertical midline groove in the chin, sclerodermatous skin, knee joints contracture with a horse-riding stance, and limited range of movement of ankle joints. Blood test showed blood platelet count (416-490) ×10(9)/L. Lower extremities MRI showed reduced subcutaneous fat. LMNA gene analysis showed that the affected-infant carried typical heterozygous mutation: c. 1824C>T (p. G608G), while his parents were normal. At the age of 13 months, X-rays showed short distal phalanges and clavicles with acro-osteolysis. After following up for 15 months, his appearance of progeria became more apparent. As far as we know, there are only 2 cases of classical HGPS confirmed by gene analysis in China.

CONCLUSIONClassical HGPS should be considered when infants appeared with sclerodermatous skin. Genetic analysis could help to diagnose classical HGPS as early as possible and avoid unnecessary investigations. In addition, affected-infants need to be long term followed-up and provided genetic counseling.

Abnormalities, Multiple ; diagnosis ; pathology ; DNA Mutational Analysis ; Diagnosis, Differential ; Hand ; diagnostic imaging ; pathology ; Humans ; Infant ; Lamin Type A ; genetics ; Lower Extremity ; diagnostic imaging ; pathology ; Male ; Mutation ; genetics ; Osteolysis, Essential ; pathology ; Progeria ; diagnosis ; genetics ; pathology ; Retrospective Studies ; Skin Diseases ; diagnosis ; genetics ; pathology ; Tomography, X-Ray Computed

OBJECTIVE: To analyze the expression of vascular endothelial growth factor (VEGF), miR-205, Ezrinand Lamin A/C in ovarian cancer tissues. METHODS: The expression of VEGF in the serum of epithelial ovarian cancer and that of healthy volunteers were detected by enzyme-linked immunosorbent assay; the expressions of vascular endothelial growth factor receptor 1 (VEGFR-1), VEGFR-2, Ezrin and Lamin A/C were detected by immunohistochemistry and the micro-vessel density (MVD) of CD31 was detected by immunohistochemistry in epithelial ovarian cancer, benign ovarian and normal ovarian specimens; and the expression of miR-205, Ezrin and Lamin A/C were detected by real-time PCR in epithelial ovarian cancer, benign ovarian and normal ovarian specimens. RESULTS: The expression of VEGF in the serum of epithelial ovarian cancer patients (116.10± 11.94) was significantly higher than that of healthy volunteers (40.04±4.97, P<0.05). The positive expression rates of VEGFR-1 and VEGFR-2 in the epithelial ovarian cancer specimens were 75.9% and 91.4% respectively, which were significantly higher than that in the benign ovarian and the normal ovarian specimens (P<0.05). No differences were observed in the positive expression rates of VEGFR-1 and VEGFR-2 between the benign ovarian and the normal ovarian specimens (P>0.05). The average length of MVD in the epithelial ovarian cancer specimens (7.56±0.51), was significantly higher than that in the normal ovarian specimens (1.22±0.56, P<0.05) and in the benign ovarian specimens (0.7±0.39, P<0.05). No differences were observed in the average length of MVD between the benign ovarian and the normal ovarian specimens (P>0.05). The relative expression level of miR-205 was 0.106±0.035 in the epithelial ovarian cancer specimens, which was significantly higher than that in the normal ovarian specimens (0.0007±0.0005, P<0.05); the relative expression level of miR-205 in the benign ovarian specimens was (0.0002±0.0002), higher than that in the normal ovarian specimens, but with no significance (P>0.05). The positive expression rates of Ezrin and Lamin A/C in the epithelial ovarian cancer specimens were 51.7% and 60.3%, respectively, which were significantly lower than those in the benign ovarian and the normal ovarian specimens (P<0.05). No differences were observed in the positive expression rates of Ezrin and Lamin A/C between the benign ovarian and the normal ovarian specimens (P>0.05). The relative expression levels of Ezrin and Lamin A/C mRNA in the epithelial ovarian cancer specimens were (0.026±0.003) and (0.060±0.007), respectively, which were significantly lower than those in the normal ovarian specimens (P<0.05). There was no statistical significance between the relative expression level of Ezrin and Lamin A/C mRNA in the epithelial ovarian cancer specimens and that in the benign ovarian specimens (0.029± 0.011, 0.089 ± 0.019; P>0.05) . CONCLUSION VEGF is significantly expressed in the serum of epithelial ovarian cancer patients; and miR-205 is up-regulated in the epithelial ovarian cancer specimens. Ezrin and Lamin A/C are down-regulated in the epithelial ovarian cancer samples. VEGF, miR-205 and target protein may be associated with the invasion and metastasis of epithelial ovarian cancer.
Carcinoma, Ovarian Epithelial ; Cytoskeletal Proteins ; genetics ; metabolism ; Down-Regulation ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Immunohistochemistry ; Lamin Type A ; genetics ; metabolism ; MicroRNAs ; genetics ; metabolism ; Neoplasms, Glandular and Epithelial ; genetics ; metabolism ; Ovarian Neoplasms ; genetics ; metabolism ; RNA, Messenger ; Real-Time Polymerase Chain Reaction ; Vascular Endothelial Growth Factor A ; blood ; Vascular Endothelial Growth Factor Receptor-1 ; metabolism ; Vascular Endothelial Growth Factor Receptor-2 ; metabolism

Through advances in technology, the genetic basis of cancer has been investigated at the genomic level, and many fundamental questions have begun to be addressed. Among several key unresolved questions in cancer biology, the molecular basis for the link between nuclear deformation and malignancy has not been determined. Another hallmark of human cancer is aneuploidy; however, the causes and consequences of aneuploidy are unanswered and are hotly contested topics. We found that nuclear lamina proteins lamin A/C are absent in a significant fraction (38%) of human breast cancer tissues. Even in lamin A/C-positive breast cancer, lamin A/C expression is heterogeneous or aberrant (such as non-nuclear distribution) in the population of tumor cells, as determined by immunohistology and immunofluorescence microscopy. In most breast cancer cell lines, a significant fraction of the lamin A/C-negative population was observed. To determine the consequences of the loss of lamin A/C, we suppressed their expression by shRNA in non-cancerous primary breast epithelial cells. Down-regulation of lamin A/C in breast epithelial cells led to morphological deformation, resembling that of cancer cells, as observed by immunofluorescence microscopy. The lamin A/C-suppressed breast epithelial cells developed aneuploidy as determined by both flow cytometry and fluorescence in situ hybridization. We conclude that the loss of nuclear envelope structural proteins lamin A/C in breast cancer underlies the two hallmarks of cancer aberrations in nuclear morphology and aneuploidy.
Aneuploidy ; Breast Neoplasms ; genetics ; metabolism ; pathology ; Cell Proliferation ; Down-Regulation ; Epithelial Cells ; metabolism ; Female ; Humans ; Lamin Type A ; genetics ; metabolism ; Mitosis ; Nuclear Envelope ; metabolism ; pathology ; Polyploidy ; RNA, Small Interfering ; genetics

Hutchinson-Gilford progeria syndrome (HGPS) is a rare condition originally described by Hutchinson in 1886. Death result from cardiac complications in the majority of cases and usually occurs at average age of thirteen years. A 4-yr old boy had typical clinical findings such as short stature, craniofacial disproportion, alopecia, prominent scalp veins and sclerodermatous skin. This abnormal appearance began at age of 1 yr. On serological and hormonal evaluation, all values are within normal range. He was neurologically intact with motor and mental development. An echocardiogram showed calcification of aortic and mitral valves. Hypertrophy of internal layer at internal carotid artery suggesting atherosclerosis was found by carotid doppler sonography. He is on low dose aspirin to prevent thromboembolic episodes and on regular follow up. Gene study showed typical G608G (GGC- > GGT) point mutation at exon 11 in LMNA gene. This is a rare case of Hutchinson-Gilford progeria syndrome confirmed by genetic analysis in Korea.
Child, Preschool ; Humans ; Lamin Type A/*genetics ; Male ; Point Mutation ; Progeria/diagnosis/*genetics ; Prognosis ; Republic of Korea