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1.
EMBO J ; 43(18): 3968-3999, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39103492

RESUMO

Senescence of nondividing neurons remains an immature concept, with especially the regulatory molecular mechanisms of senescence-like phenotypes and the role of proteins associated with neurodegenerative diseases in triggering neuronal senescence remaining poorly explored. In this study, we reveal that the nucleolar polyglutamine binding protein 3 (PQBP3; also termed NOL7), which has been linked to polyQ neurodegenerative diseases, regulates senescence as a gatekeeper of cytoplasmic DNA leakage. PQBP3 directly binds PSME3 (proteasome activator complex subunit 3), a subunit of the 11S proteasome regulator complex, decreasing PSME3 interaction with Lamin B1 and thereby preventing Lamin B1 degradation and senescence. Depletion of endogenous PQBP3 causes nuclear membrane instability and release of genomic DNA from the nucleus to the cytosol. Among multiple tested polyQ proteins, ataxin-1 (ATXN1) partially sequesters PQBP3 to inclusion bodies, reducing nucleolar PQBP3 levels. Consistently, knock-in mice expressing mutant Atxn1 exhibit decreased nuclear PQBP3 and a senescence phenotype in Purkinje cells of the cerebellum. Collectively, these results suggest homologous roles of the nucleolar protein PQBP3 in cellular senescence and neurodegeneration.


Assuntos
Senescência Celular , Lamina Tipo B , Complexo de Endopeptidases do Proteassoma , Animais , Humanos , Camundongos , Ataxina-1/metabolismo , Ataxina-1/genética , Células HEK293 , Lamina Tipo B/metabolismo , Lamina Tipo B/genética , Proteínas Nucleares/metabolismo , Proteínas Nucleares/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , Células de Purkinje/metabolismo
2.
Comput Biol Med ; 180: 108970, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39096606

RESUMO

Huntington's disease (HD) is a complex neurodegenerative disorder with considerable heterogeneity in clinical manifestations. While CAG repeat length is a known predictor of disease severity, this heterogeneity suggests the involvement of additional genetic and environmental factors. Previously we revealed that HD primary fibroblasts exhibit unique features, including distinct nuclear morphology and perturbed actin cap, resembling characteristics seen in Hutchinson-Gilford Progeria Syndrome (HGPS). This study establishes a link between actin cap deficiency and cell motility in HD, which correlates with the HD patient disease severity. Here, we examined single-cell motility imaging features in HD primary fibroblasts to explore in depth the relationship between cell migration patterns and their respective HD patients' clinical severity status (premanifest, mild and severe). The single-cell analysis revealed a decline in overall cell motility in correlation with HD severity, being most prominent in severe HD subgroup and HGPS. Moreover, we identified seven distinct spatial clusters of cell migration in all groups, which their proportion varies within each group becoming a significant HD severity classifier between HD subgroups. Next, we investigated the relationship between Lamin B1 expression, serving as nuclear envelope morphology marker, and cell motility finding that changes in Lamin B1 levels are associated with specific motility patterns within HD subgroups. Based on these data we present an accurate machine learning classifier offering comprehensive exploration of cellular migration patterns and disease severity markers for future accurate drug evaluation opening new opportunities for personalized treatment approaches in this challenging disorder.


Assuntos
Movimento Celular , Fibroblastos , Doença de Huntington , Aprendizado de Máquina , Humanos , Fibroblastos/metabolismo , Fibroblastos/patologia , Doença de Huntington/diagnóstico por imagem , Doença de Huntington/metabolismo , Doença de Huntington/patologia , Doença de Huntington/genética , Masculino , Feminino , Pele/diagnóstico por imagem , Pele/patologia , Pele/metabolismo , Progressão da Doença , Lamina Tipo B/metabolismo , Lamina Tipo B/genética , Células Cultivadas , Adulto , Pessoa de Meia-Idade
3.
Proc Natl Acad Sci U S A ; 121(27): e2406946121, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38917015

RESUMO

Progerin, the protein that causes Hutchinson-Gilford progeria syndrome, triggers nuclear membrane (NM) ruptures and blebs, but the mechanisms are unclear. We suspected that the expression of progerin changes the overall structure of the nuclear lamina. High-resolution microscopy of smooth muscle cells (SMCs) revealed that lamin A and lamin B1 form independent meshworks with uniformly spaced openings (~0.085 µm2). The expression of progerin in SMCs resulted in the formation of an irregular meshwork with clusters of large openings (up to 1.4 µm2). The expression of progerin acted in a dominant-negative fashion to disrupt the morphology of the endogenous lamin B1 meshwork, triggering irregularities and large openings that closely resembled the irregularities and openings in the progerin meshwork. These abnormal meshworks were strongly associated with NM ruptures and blebs. Of note, the progerin meshwork was markedly abnormal in nuclear blebs that were deficient in lamin B1 (~50% of all blebs). That observation suggested that higher levels of lamin B1 expression might normalize the progerin meshwork and prevent NM ruptures and blebs. Indeed, increased lamin B1 expression reversed the morphological abnormalities in the progerin meshwork and markedly reduced the frequency of NM ruptures and blebs. Thus, progerin expression disrupts the overall structure of the nuclear lamina, but that effect-along with NM ruptures and blebs-can be abrogated by increased lamin B1 expression.


Assuntos
Lamina Tipo A , Lamina Tipo B , Lâmina Nuclear , Lâmina Nuclear/metabolismo , Lamina Tipo A/metabolismo , Lamina Tipo A/genética , Lamina Tipo B/metabolismo , Lamina Tipo B/genética , Humanos , Progéria/metabolismo , Progéria/genética , Progéria/patologia , Animais , Precursores de Proteínas/metabolismo , Precursores de Proteínas/genética , Miócitos de Músculo Liso/metabolismo , Miócitos de Músculo Liso/patologia , Camundongos
4.
Mol Hum Reprod ; 30(7)2024 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-38870534

RESUMO

Acephalic spermatozoa syndrome (ASS) is a severe teratospermia with decaudated, decapitated, and malformed sperm, resulting in male infertility. Nuclear envelope protein SUN5 localizes to the junction between the sperm head and tail. Mutations in the SUN5 gene have been identified most frequently (33-47%) in ASS cases, and its molecular mechanism of action is yet to be explored. In the present study, we generated Sun5 knockout mice, which presented the phenotype of ASS. Nuclear membrane protein LaminB1 and cytoskeletal GTPases Septin12 and Septin2 were identified as potential partners for interacting with SUN5 by immunoprecipitation-mass spectrometry in mouse testis. Further studies demonstrated that SUN5 connected the nucleus by interacting with LaminB1 and connected the proximal centriole by interacting with Septin12. The binding between SUN5 and Septin12 promoted their aggregation together in the sperm neck. The disruption of the LaminB1/SUN5/Septin12 complex by Sun5 deficiency caused separation of the Septin12-proximal centriole from the nucleus, leading to the breakage of the head-to-tail junction. Collectively, these data provide new insights into the pathogenesis of ASS caused by SUN5 deficiency.


Assuntos
Proteínas de Membrana , Camundongos Knockout , Membrana Nuclear , Septinas , Cabeça do Espermatozoide , Cauda do Espermatozoide , Animais , Humanos , Masculino , Camundongos , Infertilidade Masculina/metabolismo , Infertilidade Masculina/genética , Lamina Tipo B/metabolismo , Lamina Tipo B/genética , Proteínas de Membrana/metabolismo , Proteínas de Membrana/genética , Membrana Nuclear/metabolismo , Septinas/metabolismo , Septinas/genética , Cabeça do Espermatozoide/metabolismo , Cabeça do Espermatozoide/patologia , Cauda do Espermatozoide/metabolismo , Espermatozoides/metabolismo , Teratozoospermia/metabolismo , Teratozoospermia/genética
5.
FEBS J ; 291(10): 2155-2171, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38462947

RESUMO

Mammalian somatic cells undergo terminal proliferation arrest after a limited number of cell divisions, a phenomenon termed cellular senescence. However, cells acquire the ability to proliferate infinitely (cellular immortalization) through multiple genetic alterations. Inactivation of tumor suppressor genes such as p53, RB and p16 is important for cellular immortalization, although additional molecular alterations are required for cellular immortalization to occur. Here, we aimed to gain insights into these molecular alterations. Given that cellular immortalization is the escape of cells from cellular senescence, genes that regulate cellular senescence are likely to be involved in cellular immortalization. Because senescent cells show altered heterochromatin organization, we investigated the implications of lamin A/C, lamin B1 and lamin B receptor (LBR), which regulate heterochromatin organization, in cellular immortalization. We employed human immortalized cell lines, KMST-6 and SUSM-1, and found that expression of LBR was upregulated upon cellular immortalization and downregulated upon cellular senescence. In addition, knockdown of LBR induced cellular senescence with altered chromatin configuration. Additionally, enforced expression of LBR increased cell proliferation likely through suppression of genome instability in human primary fibroblasts that expressed the simian virus 40 large T antigen (TAg), which inactivates p53 and RB. Furthermore, expression of TAg or knockdown of p53 led to upregulated LBR expression. These observations suggested that expression of LBR might be upregulated to suppress genome instability in TAg-expressing cells, and, consequently, its upregulated expression assisted the proliferation of TAg-expressing cells (i.e. p53/RB-defective cells). Our findings suggest a crucial role for LBR in the process of cellular immortalization.


Assuntos
Proliferação de Células , Senescência Celular , Instabilidade Genômica , Receptor de Lamina B , Receptores Citoplasmáticos e Nucleares , Humanos , Antígenos Transformantes de Poliomavirus/genética , Antígenos Transformantes de Poliomavirus/metabolismo , Proliferação de Células/genética , Senescência Celular/genética , Fibroblastos/metabolismo , Instabilidade Genômica/genética , Heterocromatina/genética , Heterocromatina/metabolismo , Lamina Tipo A/genética , Lamina Tipo A/metabolismo , Lamina Tipo B/genética , Lamina Tipo B/metabolismo , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Regulação para Cima
6.
Genome Biol ; 25(1): 77, 2024 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-38519987

RESUMO

BACKGROUND: B-type lamins are critical nuclear envelope proteins that interact with the three-dimensional genomic architecture. However, identifying the direct roles of B-lamins on dynamic genome organization has been challenging as their joint depletion severely impacts cell viability. To overcome this, we engineered mammalian cells to rapidly and completely degrade endogenous B-type lamins using Auxin-inducible degron technology. RESULTS: Using live-cell Dual Partial Wave Spectroscopic (Dual-PWS) microscopy, Stochastic Optical Reconstruction Microscopy (STORM), in situ Hi-C, CRISPR-Sirius, and fluorescence in situ hybridization (FISH), we demonstrate that lamin B1 and lamin B2 are critical structural components of the nuclear periphery that create a repressive compartment for peripheral-associated genes. Lamin B1 and lamin B2 depletion minimally alters higher-order chromatin folding but disrupts cell morphology, significantly increases chromatin mobility, redistributes both constitutive and facultative heterochromatin, and induces differential gene expression both within and near lamin-associated domain (LAD) boundaries. Critically, we demonstrate that chromatin territories expand as upregulated genes within LADs radially shift inwards. Our results indicate that the mechanism of action of B-type lamins comes from their role in constraining chromatin motion and spatial positioning of gene-specific loci, heterochromatin, and chromatin domains. CONCLUSIONS: Our findings suggest that, while B-type lamin degradation does not significantly change genome topology, it has major implications for three-dimensional chromatin conformation at the single-cell level both at the lamina-associated periphery and the non-LAD-associated nuclear interior with concomitant genome-wide transcriptional changes. This raises intriguing questions about the individual and overlapping roles of lamin B1 and lamin B2 in cellular function and disease.


Assuntos
Cromatina , Lamina Tipo B , Animais , Lamina Tipo B/genética , Heterocromatina , Hibridização in Situ Fluorescente , Lamina Tipo A/genética , Lamina Tipo A/metabolismo , Laminas , Expressão Gênica , Mamíferos/genética
7.
Cell Mol Life Sci ; 81(1): 141, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38485766

RESUMO

Human papillomavirus (HPV) infection is a primary cause of cervical and head-and-neck cancers. The HPV genome enters the nucleus during mitosis when the nuclear envelope disassembles. Given that lamins maintain nuclear integrity during interphase, we asked to what extent their loss would affect early HPV infection. To address this question, we infected human cervical cancer cells and keratinocytes lacking the major lamins with a HPV16 pseudovirus (HP-PsV) encoding an EGFP reporter. We found that a sustained reduction or complete loss of lamin B1 significantly increased HP-PsV infection rate. A corresponding greater nuclear HP-PsV load in LMNB1 knockout cells was directly related to their prolonged mitotic window and extensive nuclear rupture propensity. Despite the increased HP-PsV presence, EGFP transcript levels remained virtually unchanged, indicating an additional defect in protein turnover. Further investigation revealed that LMNB1 knockout led to a substantial decrease in autophagic capacity, possibly linked to the persistent activation of cGAS by cytoplasmic chromatin exposure. Thus, the attrition of lamin B1 increases nuclear perviousness and attenuates autophagic capacity, creating an environment conducive to unrestrained accumulation of HPV capsids. Our identification of lower lamin B1 levels and nuclear BAF foci in the basal epithelial layer of several human cervix samples suggests that this pathway may contribute to an increased individual susceptibility to HPV infection.


Assuntos
Lamina Tipo B , Infecções por Papillomavirus , Feminino , Humanos , Lamina Tipo B/genética , Lamina Tipo B/metabolismo , Infecções por Papillomavirus/genética , Membrana Nuclear/metabolismo , Mitose , Cromossomos/metabolismo , Lamina Tipo A/genética , Lamina Tipo A/metabolismo
8.
J Cell Physiol ; 239(5): e31213, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38308641

RESUMO

Recent studies have shown that nucleophagy can mitigate DNA damage by selectively degrading nuclear components protruding from the nucleus. However, little is known about the role of nucleophagy in neurons after spinal cord injury (SCI). Western blot analysis and immunofluorescence were performed to evaluate the nucleophagy after nuclear DNA damage and leakage in SCI neurons in vivo and NSC34 expression in primary neurons cultured with oxygen-glucose deprivation (OGD) in vitro, as well as the interaction and colocalization of autophagy protein LC3 with nuclear lamina protein Lamin B1. The effect of UBC9, a Small ubiquitin-related modifier (SUMO) E2 ligase, on Lamin B1 SUMOylation and nucleophagy was examined by siRNA transfection or 2-D08 (a small-molecule inhibitor of UBC9), immunoprecipitation, and immunofluorescence. In SCI and OGD injured NSC34 or primary cultured neurons, neuronal nuclear DNA damage induced the SUMOylation of Lamin B1, which was required by the nuclear Lamina accumulation of UBC9. Furthermore, LC3/Atg8, an autophagy-related protein, directly bound to SUMOylated Lamin B1, and delivered Lamin B1 to the lysosome. Knockdown or suppression of UBC9 with siRNA or 2-D08 inhibited SUMOylation of Lamin B1 and subsequent nucleophagy and protected against neuronal death. Upon neuronal DNA damage and leakage after SCI, SUMOylation of Lamin B1 is induced by nuclear Lamina accumulation of UBC9. Furthermore, it promotes LC3-Lamin B1 interaction to trigger nucleophagy that protects against neuronal DNA damage.


Assuntos
Autofagia , Dano ao DNA , Lamina Tipo B , Neurônios , Traumatismos da Medula Espinal , Sumoilação , Enzimas de Conjugação de Ubiquitina , Animais , Camundongos , Núcleo Celular/metabolismo , Lamina Tipo B/metabolismo , Lamina Tipo B/genética , Neurônios/metabolismo , Neurônios/patologia , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/genética , Traumatismos da Medula Espinal/patologia , Enzimas de Conjugação de Ubiquitina/metabolismo , Enzimas de Conjugação de Ubiquitina/genética , Camundongos Endogâmicos C57BL , Linhagem Celular Tumoral
9.
Curr Opin Cell Biol ; 86: 102313, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38262116

RESUMO

The nuclear lamina (NL) is a crucial component of the inner nuclear membrane (INM) and consists of lamin filaments and associated proteins. Lamins are type V intermediate filament proteins essential for maintaining the integrity and mechanical properties of the nucleus. In human cells, 'B-type' lamins (lamin B1 and lamin B2) are ubiquitously expressed, while 'A-type' lamins (lamin A, lamin C, and minor isoforms) are expressed in a tissue- and development-specific manner. Lamins homopolymerize to form filaments that localize primarily near the INM, but A-type lamins also localize to and function in the nucleoplasm. Lamins play central roles in the assembly, structure, positioning, and mechanics of the nucleus, modulating cell signaling and influencing development, differentiation, and other activities. This review highlights recent findings on the structure and regulation of lamin filaments, providing insights into their multifaceted functions, including their role as "mechanosensors", delving into the emerging significance of lamin filaments as vital links between cytoskeletal and nuclear structures, chromatin organization, and the genome.


Assuntos
Lamina Tipo B , Lâmina Nuclear , Humanos , Laminas/metabolismo , Lamina Tipo B/genética , Lamina Tipo B/metabolismo , Lâmina Nuclear/metabolismo , Membrana Nuclear/metabolismo , Núcleo Celular/metabolismo , Filamentos Intermediários/metabolismo , Diferenciação Celular
10.
J Cell Biol ; 223(2)2024 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-38261271

RESUMO

The nuclear lamina (NL) plays various roles and participates in nuclear integrity, chromatin organization, and transcriptional regulation. Lamin proteins, the main components of the NL, form a homogeneous meshwork structure under the nuclear envelope. Lamins are essential, but it is unknown whether their homogeneous distribution is important for nuclear function. Here, we found that PIGB, an enzyme involved in glycosylphosphatidylinositol (GPI) synthesis, is responsible for the homogeneous lamin meshwork in Drosophila. Loss of PIGB resulted in heterogeneous distributions of B-type lamin and lamin-binding proteins in larval muscles. These phenotypes were rescued by expression of PIGB lacking GPI synthesis activity. The PIGB mutant exhibited changes in lamina-associated domains that are large heterochromatic genomic regions in the NL, reduction of nuclear stiffness, and deformation of muscle fibers. These results suggest that PIGB maintains the homogeneous meshwork of the NL, which may be essential for chromatin distribution and nuclear mechanical properties.


Assuntos
Proteínas de Drosophila , Drosophila , Músculo Esquelético , Lâmina Nuclear , Animais , Lamina Tipo B/genética , Fibras Musculares Esqueléticas/fisiologia , Músculo Esquelético/fisiologia , Lâmina Nuclear/fisiologia , Proteínas de Drosophila/genética , Proteínas de Drosophila/fisiologia , Glicosilfosfatidilinositóis/metabolismo
11.
Arch Virol ; 169(2): 36, 2024 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-38265511

RESUMO

Current therapies for hepatitis B virus (HBV) infection can slow disease progression but cannot cure the infection, as it is difficult to eliminate or permanently silence HBV covalently closed circular DNA (cccDNA). The interaction between host factors and cccDNA is essential for their formation, stability, and transcriptional activity. Here, we focused on the regulatory role of the host factor ENPP1 and its interacting transcription factor LMNB1 in HBV replication and transcription to better understand the network of host factors that regulate HBV, which may facilitate the development of new antiviral drugs. Overexpression of ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) in Huh7 cells decreased HBV pregenomic RNA (pgRNA) and hepatitis B core antigen (HBcAg) expression levels, whereas knockdown of ENPP1 increased them. A series of HBV promoter and mutant plasmids were constructed, and a luciferase reporter assay showed that overexpression of ENPP1 caused inhibition of the HBV promoter and its mutants. A DNA pull-down assay showed that lamin B1 (LMNB1), but not ENPP1, interacts directly with the HBV enhancer II/ basic core promoter (EnhII/BCP). ZDOCK and PyMOL software were used to predict the interaction of ENPP1 with LMNB1. Overexpression of LMNB1 inhibited the activity of the HBV promoter and its mutant. The acetylation levels at the amino acids 111K, 261K, and 483K of LMNB1 were reduced compared to the control, and an LMNB1 acetylation mutant containing 111R, 261Q, 261R, 483Q, and 483R showed increased promoter activity. In summary, ENPP1 together with LMNB1 increased the acetylation level at 111K and 261K, and LMNB1 inhibited the activity of HBV promoter and downregulated the expression of pregenomic RNA and HBcAg. Our follow-up studies will investigate the expression, clinical significance, and relevance of ENPP1 and LMNB1 in HBV patient tissues, explore the effect of LMNB1 on post-transcriptional progression, and examine whether ENPP1 can reduce cccDNA levels in the nucleus.


Assuntos
Vírus da Hepatite B , Lamina Tipo B , Diester Fosfórico Hidrolases , Pirofosfatases , Humanos , Acetilação , Hepatite B , Antígenos do Núcleo do Vírus da Hepatite B , Vírus da Hepatite B/genética , Lamina Tipo B/genética , Diester Fosfórico Hidrolases/genética , Pirofosfatases/genética , RNA
12.
Endocr Relat Cancer ; 31(3)2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38224097

RESUMO

Adrenocortical carcinoma (ACC) is a malignancy with a poor prognosis and high mortality rate. A high tumor mutational burden (TMB) has been found to be associated with poor prognosis in ACC. Thus, exploring ACC biomarkers based on TMB holds significant importance for patient risk stratification. In our research, we utilized weighted gene coexpression network analysis and an assay for transposase-accessible chromatin with high-throughput sequencing to identify genes associated with TMB. Through the comprehensive analysis of various public datasets, Lamin B1 (LMNB1) was identified as a biomarker associated with a high TMB and low chromatin accessibility. Immunohistochemical staining demonstrated high expression of LMNB1 in ACC compared to noncancerous tissues. Functional enrichment analyses revealed that the function of LMNB1 is associated with cell proliferation and division. Furthermore, cell assays suggested that LMNB1 promotes tumor proliferation and invasion. In addition, mutation analysis suggested that the high expression of LMNB1 is associated with TP53 mutations. Additionally, LMNB1 was highly expressed in the vast majority of solid tumors across cancers. In our immune analysis, we discovered that the high expression of LMNB1 might suppress the infiltration of CD8+ T cells in the ACC microenvironment. In summary, LMNB1 is a predictive factor for the poor prognosis of adult and pediatric ACC. Its high expression in ACC is positively associated with high TMB and lower chromatin accessibility, and it promotes ACC cell proliferation and invasion. Therefore, LMNB1 holds promise as a novel biomarker and potential therapeutic target for ACC.


Assuntos
Carcinoma Adrenocortical , Lamina Tipo B , Adulto , Criança , Humanos , Carcinoma Adrenocortical/genética , Biomarcadores , Biomarcadores Tumorais/genética , Cromatina , Lamina Tipo B/genética , Lamina Tipo B/metabolismo , Prognóstico , Microambiente Tumoral
13.
Acta Myol ; 42(2-3): 43-52, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38090549

RESUMO

Lamins A/C (encoded by LMNA gene) can lead to dilated cardiomyopathy (DCM). This pilot study sought to explore the postgenomic phenotype of end-stage lamin heart disease. Consecutive patients with end-stage lamin heart disease (LMNA-group, n = 7) and ischaemic DCM (ICM-group, n = 7) undergoing heart transplantation were prospectively enrolled. Samples were obtained from left atrium (LA), left ventricle (LV), right atrium (RA), right ventricle (RV) and interventricular septum (IVS), avoiding the infarcted myocardial segments in the ICM-group. Samples were analysed using a discovery 'shotgun' proteomics approach. We found that 990 proteins were differentially abundant between LMNA and ICM samples with the LA being most perturbed (16-fold more than the LV). Abundance of lamin A/C protein was reduced, but lamin B increased in LMNA LA/RA tissue compared to ICM, but not in LV/RV. Carbonic anhydrase 3 (CA3) was over-abundant across all LMNA tissue samples (LA, LV, RA, RV, and IVS) when compared to ICM. Transthyretin was more abundant in the LV/RV of LMNA compared to ICM, while sarcomeric proteins such as titin and cardiac alpha-cardiac myosin heavy chain were generally less abundant in RA/LA of LMNA. Protein expression profiling and enrichment analysis pointed towards sarcopenia, extracellular matrix remodeling, deficient myocardial energetics, redox imbalances, and abnormal calcium handling in LMNA samples. Compared to ICM, end-stage lamin heart disease is a biventricular but especially a biatrial disease appearing to have an abundance of lamin B, CA3 and transthyretin, potentially hinting to compensatory responses.


Assuntos
Cardiomiopatia Dilatada , Ventrículos do Coração , Humanos , Proteoma/genética , Pré-Albumina/genética , Lamina Tipo B/genética , Projetos Piloto , Cardiomiopatia Dilatada/genética , Lamina Tipo A/genética , Átrios do Coração/metabolismo , Mutação
14.
Curr Opin Cell Biol ; 85: 102257, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37806292

RESUMO

The role of lamin B1 in human health and aging has attracted increasing attention as mounting evidence reveals its significance in diverse cellular processes. Both upregulation and downregulation of lamin B1 have been implicated in age-associated organ dysfunctions and various human diseases, including central nervous system disorders. Additionally, lamin B1 levels undergo alterations in cancer cells, and a tumor-specific association exists between lamin B1 abundance and cancer aggressiveness. Investigating the connectivity between lamin B1 abundance and human health is of utmost importance for further research. This review presents recent advancements in understanding lamin B1's role in nuclear lamina function and its implications for human health.


Assuntos
Envelhecimento , Lâmina Nuclear , Humanos , Envelhecimento/patologia , Lamina Tipo B/genética , Neoplasias/patologia , Lâmina Nuclear/patologia
15.
J Cell Biol ; 222(11)2023 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-37695420

RESUMO

Cells migrate collectively through confined environments during development and cancer metastasis. The nucleus, a stiff organelle, impedes single cells from squeezing into narrow channels within artificial environments. However, how nuclei affect collective migration into compact tissues is unknown. Here, we use border cells in the fly ovary to study nuclear dynamics in collective, confined in vivo migration. Border cells delaminate from the follicular epithelium and squeeze into tiny spaces between cells called nurse cells. The lead cell nucleus transiently deforms within the lead cell protrusion, which then widens. The nuclei of follower cells deform less. Depletion of the Drosophila B-type lamin, Lam, compromises nuclear integrity, hinders expansion of leading protrusions, and impedes border cell movement. In wildtype, cortical myosin II accumulates behind the nucleus and pushes it into the protrusion, whereas in Lam-depleted cells, myosin accumulates but does not move the nucleus. These data suggest that the nucleus stabilizes lead cell protrusions, helping to wedge open spaces between nurse cells.


Assuntos
Movimento Celular , Lâmina Nuclear , Ovário , Animais , Feminino , Núcleo Celular , Drosophila , Filamentos Intermediários , Lamina Tipo B/genética , Ovário/citologia
16.
PLoS Genet ; 19(6): e1010805, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37347778

RESUMO

Pelger-Huët anomaly (PHA) in humans is an autosomal dominant hematological phenotype without major clinical consequences. PHA involves a characteristic hyposegmentation of granulocytes (HG). Human PHA is caused by heterozygous loss of function variants in the LBR gene encoding lamin receptor B. Bi-allelic variants and complete deficiency of LBR cause the much more severe Greenberg skeletal dysplasia which is lethal in utero and characterized by massive skeletal malformation and gross fetal hydrops. HG phenotypes have also been described in domestic animals and homology to human PHA has been claimed in the literature. We studied a litter of Australian Shepherd Dogs with four stillborn puppies in which both parents had an HG phenotype. Linkage analysis excluded LBR as responsible gene for the stillborn puppies. We then investigated the HG phenotype in Australian Shepherd Dogs independently of the prenatal lethality. Genome-wide association mapped the HG locus to chromosome 27 and established an autosomal recessive mode of inheritance. Whole genome sequencing identified a splice site variant in LMBR1L, c.191+1G>A, as most likely causal variant for the HG phenotype. The mutant allele abrogates the expression of the longer X2 isoform but does not affect transcripts encoding the shorter X1 isoform of the LMBR1L protein. The homozygous mutant LMBR1L genotype associated with HG is common in Australian Shepherd Dogs and was found in 39 of 300 genotyped dogs (13%). Our results point to a previously unsuspected function of LMBR1L in the myeloid lineage of leukocytes.


Assuntos
Estudo de Associação Genômica Ampla , Anomalia de Pelger-Huët , Feminino , Gravidez , Cães , Humanos , Animais , Receptores Citoplasmáticos e Nucleares/genética , Austrália , Granulócitos , Genótipo , Anomalia de Pelger-Huët/genética , Lamina Tipo B/genética , Receptores de Superfície Celular/genética
17.
Exp Cell Res ; 426(2): 113573, 2023 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-37003558

RESUMO

Ovarian cancer (OC) is a common malignant tumor in gynecology. LMNB1 is an important component of the nuclear skeleton. The expression of LMNB1 in ovarian cancer is significantly higher than that in normal tissues, but its role in tumor still needs comprehensive investigation. In this study, we overexpressed and knocked down LMNB1 in ovarian cancer cells and explore the effect of LMNB1 on the cell proliferation, migration and the underlying mechanism. We analyzed the expression levels of LMNB1 in ovarian cancer and their clinical relevance by using bioinformatics methods, qRT-PCR, Western blot and immunohistochemistry. To state the effect and mechanism of LMNB1 on OC in vitro and in vivo, we performed mouse xenograft studies, CCK8, cloning formation, Edu incorporation, wound healing, transwell and flow cytometry assay in stable LMNB1 knockdown OC cells, following by RNA-seq. Overexpression of LMNB1 indicates the progression of OC. LMNB1 knockdown inhibited the proliferation and migration of OC cells by suppressing the FGF1-mediated PI3K-Akt signaling pathway. Our study shows LMNB1 as a novel prognostic factor and therapeutic target in OC.


Assuntos
Lamina Tipo B , Neoplasias Ovarianas , Proteínas Proto-Oncogênicas c-akt , Animais , Feminino , Humanos , Camundongos , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Neoplasias Ovarianas/patologia , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Lamina Tipo B/genética , Deleção de Genes
18.
Nucleus ; 14(1): 2202548, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37071033

RESUMO

Peripheral heterochromatin positioning depends on nuclear envelope associated proteins and repressive histone modifications. Here we show that overexpression (OE) of Lamin B1 (LmnB1) leads to the redistribution of peripheral heterochromatin into heterochromatic foci within the nucleoplasm. These changes represent a perturbation of heterochromatin binding at the nuclear periphery (NP) through a mechanism independent from altering other heterochromatin anchors or histone post-translational modifications. We further show that LmnB1 OE alters gene expression. These changes do not correlate with different levels of H3K9me3, but a significant number of the misregulated genes were likely mislocalized away from the NP upon LmnB1 OE. We also observed an enrichment of developmental processes amongst the upregulated genes. ~74% of these genes were normally repressed in our cell type, suggesting that LmnB1 OE promotes gene de-repression. This demonstrates a broader consequence of LmnB1 OE on cell fate, and highlights the importance of maintaining proper levels of LmnB1.


Assuntos
Heterocromatina , Lamina Tipo B , Heterocromatina/genética , Heterocromatina/metabolismo , Lamina Tipo B/genética , Lamina Tipo B/metabolismo , Núcleo Celular/metabolismo , Expressão Gênica
19.
Gene ; 870: 147423, 2023 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-37044185

RESUMO

Lamin B2 (LMNB2), on the inner side of the nuclear envelope, constitutes the nuclear skeleton by connecting with other nuclear proteins. LMNB2 is involved in a wide range of nuclear functions, including DNA replication and stability, regulation of chromatin, and nuclear stiffness. Moreover, LMNB2 regulates several cellular processes, such as tissue development, cell cycle, cellular proliferation and apoptosis, chromatin localization and stability, and DNA methylation. Besides, the influence of abnormal expression and mutations of LMNB2 has been gradually discovered in cancers and laminopathies. Therefore, this review summarizes the recent advances of LMNB2-associated biological roles in physiological or pathological conditions, with a particular emphasis on cancers and laminopathies, as well as the potential mechanism of LMNB2 in related cancers.


Assuntos
Lamina Tipo B , Laminopatias , Neoplasias , Proteínas Nucleares , Humanos , Núcleo Celular/metabolismo , Cromatina/genética , Cromatina/metabolismo , Lamina Tipo A/genética , Lamina Tipo A/metabolismo , Lamina Tipo B/genética , Lamina Tipo B/metabolismo , Membrana Nuclear/genética , Membrana Nuclear/metabolismo , Proteínas Nucleares/genética , Laminopatias/metabolismo , Neoplasias/metabolismo
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