RESUMO
Liver regeneration is an intricate pathophysiological process that has been a subject of great interest to the scientific community for many years. The capacity of liver regeneration is very critical for patients with liver diseases. Therefore, exploring the mechanisms of liver regeneration and finding good ways to improve it are very meaningful. Mesencephalic astrocyte-derived neurotrophic factor (MANF), a member of newly identified neurotrophic factors (NTFs) family, extensively expresses in the liver and has demonstrated cytoprotective effects during ER stress and inflammation. However, the role of MANF in liver regeneration remains unclear. Here, we used hepatocyte-specific MANF knockout (MANFHep-/-) mice to investigate the role of MANF in liver regeneration after 2/3 partial hepatectomy (PH). Our results showed that MANF expression was up-regulated in a time-dependent manner, and the peak level of mRNA and protein appeared at 24 h and 36 h after 2/3 PH, respectively. Notably, MANF knockout delayed hepatocyte proliferation, and the peak proliferation period was delayed by 24 h. Mechanistically, our in vitro results showed that MANF physically interacts with LRP5 and ß-catenin, two essential components of Wnt/ß-catenin pathway. Specifically, as a cofactor, MANF binds to the extracellular segment of LRP5 to activate Wnt/ß-catenin signaling. On the other hand, MANF interacts with ß-catenin to stabilize cytosolic ß-catenin level and promote its nuclear translocation, which further enhance the Wnt/ß-catenin signaling. We also found that MANF knockout does not affect the c-Met/ß-catenin complex after 2/3 PH. In summary, our study confirms that MANF may serve as a novel hepatocyte factor that is closely linked to the activation of the Wnt/ß-catenin pathway via intracellular and extracellular targets.
Assuntos
Proliferação de Células , Hepatectomia , Hepatócitos , Regeneração Hepática , Camundongos Knockout , Fatores de Crescimento Neural , Via de Sinalização Wnt , beta Catenina , Regeneração Hepática/fisiologia , Animais , Fatores de Crescimento Neural/metabolismo , Fatores de Crescimento Neural/genética , Hepatócitos/metabolismo , beta Catenina/metabolismo , Camundongos , Humanos , Camundongos Endogâmicos C57BL , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Masculino , Fígado/metabolismoRESUMO
Steroid-induced osteonecrosis of the femoral head (SONFH) is a prevalent form of osteonecrosis in young individuals. More efficacious clinical strategies must be used to prevent and treat this condition. One of the mechanisms through which SONFH operates is the disruption of normal differentiation in bone marrow adipocytes and osteoblasts due to prolonged and extensive use of glucocorticoids (GCs). In vitro, it was observed that atorvastatin (ATO) effectively suppressed the impact of dexamethasone (DEX) on bone marrow mesenchymal stem cells (BMSCs), specifically by augmenting their lipogenic differentiation while impeding their osteogenic differentiation. To investigate the underlying mechanisms further, we conducted transcriptome sequencing of BMSCs subjected to different treatments, leading to the identification of Wnt5a as a crucial gene regulated by ATO. The analyses showed that ATO exhibited the ability to enhance the expression of Wnt5a and modulate the MAPK pathway while regulating the Wnt canonical signaling pathway via the WNT5A/LRP5 pathway. Our experimental findings provide further evidence that the combined treatment of ATO and DEX effectively mitigates the effects of DEX, resulting in the upregulation of osteogenic genes (Runx2, Alpl, Tnfrsf11b, Ctnnb1, Col1a) and the downregulation of adipogenic genes (Pparg, Cebpb, Lpl), meanwhile leading to the upregulation of Wnt5a expression. So, this study offers valuable insights into the potential mechanism by which ATO can be utilized in the prevention of SONFH, thereby holding significant implications for the prevention and treatment of SONFH in clinical settings.
Assuntos
Atorvastatina , Dexametasona , Necrose da Cabeça do Fêmur , Glucocorticoides , Células-Tronco Mesenquimais , Osteogênese , Proteína Wnt-5a , Proteína Wnt-5a/metabolismo , Proteína Wnt-5a/genética , Atorvastatina/farmacologia , Animais , Necrose da Cabeça do Fêmur/induzido quimicamente , Necrose da Cabeça do Fêmur/prevenção & controle , Dexametasona/farmacologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Glucocorticoides/farmacologia , Osteogênese/efeitos dos fármacos , Masculino , Diferenciação Celular/efeitos dos fármacos , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Via de Sinalização Wnt/efeitos dos fármacos , Ratos Sprague-Dawley , Células Cultivadas , Adipogenia/efeitos dos fármacos , RatosRESUMO
Low-density lipoprotein receptor-related protein 5 (LRP5) is a constitutively expressed receptor with observed roles in bone homeostasis, retinal development, and cardiac metabolism. However, the function of LRP5 in the brain remains unexplored. This study investigates LRP5's role in the central nervous system by conducting an extensive analysis using RNA-seq tools and in silico assessments. Two protein-coding Lrp5 transcripts are expressed in mice: full-length Lrp5-201 and a truncated form encoded by Lrp5-202. Wt mice express Lrp5-201 in the liver and brain and do not express the truncated form. Lrp5-/- mice express Lrp5-202 in the liver and brain and do not express Lrp5-201 in the liver. Interestingly, Lrp5-/- mouse brains show full-length Lrp5-201 expression, suggesting that LRP5 has a role in preserving brain function during development. Functional gene enrichment analysis on RNA-seq unveils dysregulated expression of genes associated with neuronal differentiation and synapse formation in the brains of Lrp5-/- mice compared to Wt mice. Furthermore, Gene Set Enrichment Analysis highlights downregulated expression of genes involved in retinol and linoleic acid metabolism in Lrp5-/- mouse brains. Tissue-specific alternative splicing of Lrp5 in Lrp5-/- mice supports that the expression of LRP5 in the brain is needed for the correct synthesis of vitamins and fatty acids, and it is indispensable for correct brain development.
Assuntos
Processamento Alternativo , Encéfalo , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Animais , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Encéfalo/metabolismo , Encéfalo/crescimento & desenvolvimento , Camundongos , Camundongos Knockout , Fígado/metabolismo , Fígado/crescimento & desenvolvimento , Camundongos Endogâmicos C57BLRESUMO
Gain-of-function mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) can cause high-bone-mass (HBM) phenotype, with 19 identified mutations so far. The A242T mutation in LRP5 has been found in 9 families, making it one of the most prevalent mutations. However, the correlation between the A242T mutation and HBM phenotype remains unverified in animal models. This study aimed to investigate the bone properties in a new transgenic mouse model carrying the LRP5 A241T missense mutation, equivalent to A242T in humans. Heterozygous Lrp5A241T mice were generated using CRISPR/Cas9 genome editing. Body weight increased with age from 4 to 16 weeks, higher in males than females, with no difference between Lrp5A241T mice and wild-type control. Micro-CT showed slightly longer femur and notably elevated trabecular bone mass of the femur and fifth lumbar spine with higher bone mineral density, bone volume fraction, and trabecular thickness in Lrp5A241T mice compared to wild-type mice. Additionally, increased cortical bone thickness and volume of the femur shaft and skull were observed in Lrp5A241T mice. Three-point bending tests of the tibia demonstrated enhanced bone strength properties in Lrp5A241T mice. Histomorphometry confirmed that the A241T mutation increased bone formation without affecting osteoblast number and reduced resorption activities in vivo. In vitro experiments indicated that the LRP5 A241T mutation enhanced osteogenic capacity of osteoblasts with upregulation of the Wnt signaling pathway, with no significant impact on the resorptive activity of osteoclasts. In summary, mice carrying the LRP5 A241T mutation displayed high bone mass and quality due to enhanced bone formation and reduced bone resorption in vivo, potentially mediated by the augmented osteogenic potential of osteoblasts. Continued investigation into the regulatory mechanisms of its bone metabolism and homeostasis may contribute to the advancement of novel therapeutic strategies for bone disorders.
Assuntos
Densidade Óssea , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Camundongos Transgênicos , Fenótipo , Animais , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Feminino , Masculino , Densidade Óssea/genética , Osteoblastos/metabolismo , Mutação/genética , Camundongos , Osso e Ossos/metabolismo , Osso e Ossos/diagnóstico por imagem , Osso e Ossos/patologia , Microtomografia por Raio-X , Tamanho do Órgão , Osteogênese/genética , Peso Corporal/genética , Fêmur/diagnóstico por imagem , Fêmur/patologia , Fêmur/metabolismo , Osteoclastos/metabolismoRESUMO
Hydrolyzed egg yolk peptide (YPEP) was shown to increase bone mineral density in ovariectomized rats. However, the underlying mechanism of YPEP on osteoporosis has not been explored. Recent studies have shown that Wnt/ß-catenin signaling pathway and gut microbiota may be involved in the regulation of bone metabolism and the progression of osteoporosis. The present study aimed to explore the preventive effect of the YPEP supplementation on osteoporosis in ovariectomized (OVX) rats and to verify whether YPEP can improve osteoporosis by regulating Wnt/ß-catenin signaling pathway and gut microbiota. The experiment included five groups: sham surgery group (SHAM), ovariectomy group (OVX), 17-ß estradiol group (E2: 25 µg /kg/d 17ß-estradiol), OVX with low-dose YPEP group (LYPEP: 10 mg /kg/d YPEP) and OVX with high-dose YPEP group (HYPEP: 40 mg /kg/d YPEP). In this study, all the bone samples used were femurs. Micro-CT analysis revealed improvements in both bone mineral density (BMD) and microstructure by YPEP treatment. The three-point mechanical bending test indicated an enhancement in the biomechanical properties of the YPEP groups. The serum levels of bone alkaline phosphatase (BALP), bone gla protein (BGP), calcium (Ca), and phosphorus (P) were markedly higher in the YPEP groups than in the OVX group. The LYPEP group had markedly lower levels of alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (TRAP) and C-terminal telopeptide of type I collagen (CTX-I) than the OVX group. The YPEP groups had significantly higher protein levels of the Wnt3a, ß-catenin, LRP5, RUNX2 and OPG of the Wnt/ß-catenin signaling pathway compared with the OVX group. Compared to the OVX group, the ratio of OPG/RANKL was markedly higher in the LYPEP group. At the genus level, there was a significantly increase in relative abundance of Lachnospiraceae_NK4A136_group and a decrease in Escherichia_Shigella in YPEP groups, compared with the OVX group. However, in the correlation analysis, there was no correlation between these two bacteria and bone metabolism and microstructure indexes. These findings demonstrate that YPEP has the potential to improve osteoporosis, and the mechanism may be associated with its modulating effect on Wnt/ß-catenin signaling pathway.
Assuntos
Densidade Óssea , Osteoporose , Ovariectomia , Via de Sinalização Wnt , Animais , Feminino , Ratos , Fosfatase Alcalina/metabolismo , beta Catenina/metabolismo , Densidade Óssea/efeitos dos fármacos , Proteínas do Ovo/farmacologia , Proteínas do Ovo/metabolismo , Gema de Ovo/química , Gema de Ovo/metabolismo , Fêmur/efeitos dos fármacos , Fêmur/metabolismo , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Osteoporose/prevenção & controle , Osteoporose/metabolismo , Peptídeos/farmacologia , Ratos Sprague-Dawley , Via de Sinalização Wnt/efeitos dos fármacos , Microtomografia por Raio-XRESUMO
BACKGROUND AND PURPOSE: Insulin and exenatide are two hypoglycaemic agents that exhibit different osteogenic effects. This study compared the differences between exenatide and insulin in osseointegration in a rat model of Type 2 diabetes (T2D) and explored the mechanisms promoting osteogenesis in this model of T2D. EXPERIMENTAL APPROACH: In vivo, micro-CT was used to detect differences in the peri-implant bone microstructure in vivo. Histology, dual-fluorescent labelling, immunofluorescence and immunohistochemistry were used to detect differences in tissue, cell and protein expression around the implants. In vitro, RT-PCR and western blotting were used to measure the expression of osteogenesis- and Wnt signalling-related genes and proteins in bone marrow mesenchymal stromal cells (BMSCs) from rats with T2D (TBMSCs) after PBS, insulin and exenatide treatment. RT-PCR was used to detect the expression of Wnt bypass cascade reactions under Wnt inactivation. KEY RESULTS: Micro-CT and section staining showed exenatide extensively promoted peri-implant osseointegration. Both in vivo and in vitro experiments showed exenatide substantially increased the expression of osteogenesis-related and activated the LRP5/6/GSK-3ß/ß-catenin-related Wnt pathway. Furthermore, exenatide suppressed expression of Bmpr1a to inhibit lipogenesis and promoted expression of Btrc to suppress inflammation. CONCLUSION AND IMPLICATIONS: Compared to insulin, exenatide significantly improved osteogenesis in T2D rats and TBMSCs. In addition to its dependence on LRP5/6/GSK-3ß/ß-catenin signalling for osteogenic differentiation, exenatide-mediated osteomodulation also involves inhibition of inflammation and adipogenesis by BMPR1A and ß-TrCP, respectively.
Assuntos
Diabetes Mellitus Tipo 2 , Exenatida , Insulina , Osteogênese , beta Catenina , Animais , Masculino , Ratos , beta Catenina/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/tratamento farmacológico , Exenatida/farmacologia , Exenatida/administração & dosagem , Glicogênio Sintase Quinase 3 beta/metabolismo , Hipoglicemiantes/farmacologia , Insulina/metabolismo , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Osseointegração/efeitos dos fármacos , Osteogênese/efeitos dos fármacos , Ratos Sprague-DawleyRESUMO
Environmental factors and genetic variation individually impact bone. However, it is not clear how these factors interact to influence peak bone mass accrual. Here we tested whether genetically programmed high bone formation driven by missense mutations in the Lrp5 gene (Lrp5A214V) altered the sensitivity of mice to an environment of inadequate dietary calcium (Ca) intake. Weanling male Lrp5A214V mice and wildtype littermates (control) were fed AIN-93G diets with 0.125%, 0.25%, 0.5% (reference, basal), or 1% Ca from weaning until 12 weeks of age (ie, during bone growth). Urinary Ca, serum Ca, Ca regulatory hormones (PTH, 1,25 dihydroxyvitamin D3 (1,25(OH)2D3)), bone parameters (µCT, ash), and renal/intestinal gene expression were analyzed. As expected, low dietary Ca intake negatively impacted bones and Lrp5A214V mice had higher bone mass and ash content. Although bones of Lrp5A214V mice have more matrix to mineralize, their bones were not more susceptible to low dietary Ca intake. In control mice, low dietary Ca intake exerted expected effects on serum Ca (decreased), PTH (increased), and 1,25(OH)2D3 (increased) as well as their downstream actions (ie, reducing urinary Ca, increasing markers of intestinal Ca absorption). In contrast, Lrp5A214V mice had elevated serum Ca with a normal PTH response but a blunted 1,25(OH)2D3 response to low dietary Ca that was reflected in the renal 1,25(OH)2D3 producing/degrading enzymes, Cyp27b1 and Cyp24a1. Despite elevated serum Ca in Lrp5A214V mice, urinary Ca was not elevated. Despite an abnormal serum 1,25(OH)2D3 response to low dietary Ca, intestinal markers of Ca absorption (Trpv6, S100g mRNA) were elevated in Lrp5A214V mice and responded to low Ca intake. Collectively, our data indicate that the Lrp5A214V mutation induces changes in Ca homeostasis that permit mice to retain more Ca and support their high bone mass phenotype.
Optimizing peak bone mass (PBM) is critical for strong bones and osteoporosis prevention. Both genetics and dietary factors like calcium (Ca) contribute to PBM. The goal of this research study was to determine how dietary Ca intake and genetics interact with each other to impact bone mass. Lowering dietary Ca in control mice causes hormonal changes that increase intestinal Ca absorption and reduce urinary Ca loss to protect bone; but this process fails when dietary Ca becomes too low. However, mice with genetically programmed high bone mass could maintain high bone mass even when challenged with Ca deficient diets. This protection is because the high bone mass mice maintain higher serum Ca, have altered production and utilization of Ca-regulating hormones, and have increased molecular indicators of intestinal Ca absorption and kidney Ca retention. Our findings are important because they demonstrate how a genetic program that increases bone formation can drive improved efficiency of Ca utilization to accommodate the increased need for Ca deposition into bone. We believe that our preclinical study provides important proof-of-principle support for the concept of personalized recommendations for bone health management.
Assuntos
Cálcio da Dieta , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Animais , Masculino , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Cálcio da Dieta/farmacologia , Cálcio da Dieta/metabolismo , Camundongos , Vitamina D/metabolismo , Vitamina D/farmacologia , Vitamina D/administração & dosagem , Hormônio Paratireóideo/sangue , Hormônio Paratireóideo/metabolismo , Osso e Ossos/metabolismo , Osso e Ossos/efeitos dos fármacos , Densidade Óssea/efeitos dos fármacos , Cálcio/metabolismo , Cálcio/urina , Calcitriol/sangue , Calcitriol/farmacologia , Calcitriol/metabolismo , Tamanho do Órgão/efeitos dos fármacosRESUMO
The study investigated the potential association of the low-density lipoprotein (LDL) genome with endometrial cancer progression based on the Gene Expression Omnibus data set and The Cancer Genome Atlas data set. Differential and weighted gene coexpression network analysis was performed on endometrial cancer transcriptome datasets GSE9750 and GSE106191. The protein-protein interaction network was built using LDL-receptor proteins and the top 50 tumor-associated genes. Low-density lipoprotein-related receptors 5/6 (LRP5/6) in endometrial cancer tissues were correlated with oncogenes, cell cycle-related genes, and immunological checkpoints using Spearman correlation. MethPrimer predicted the LRP5/6 promoter CpG island. LRP2, LRP6, LRP8, LRP12, low-density lipoprotein receptor-related protein-associated protein, and LRP5 were major LDL-receptor-related genes associated with endometrial cancer. LRP5/6 was enriched in various cancer-related pathways and may be a key LDL-receptor-related gene in cancer progression. LRP5/6 may be involved in the proliferation process of endometrial cancer cells by promoting the expression of cell cycle-related genes. LRP5/6 may be involved in the proliferation of endometrial cancer cells by promoting the expression of cell cycle-related genes. LRP5/6 may promote the immune escape of cancer cells by promoting the expression of immune checkpoints, promoting endometrial cancer progression. The MethPrimer database predicted that the LRP5/6 promoter region contained many CpG islands, suggesting that DNA methylation can occur in the LRP5/6 promoter region. LRP5/6 may aggravate endometrial cancer by activating the phosphoinositide 3-kinase/protein kinase B pathway.
Assuntos
Neoplasias do Endométrio , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Humanos , Feminino , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Fosfatidilinositol 3-Quinases , Receptores de LDL , Neoplasias do Endométrio/genética , Lipoproteínas LDLRESUMO
AIMS: There is little information on the regulation of cholesterol homeostasis in the brain. Whether cholesterol crosses the blood-brain barrier is under investigation, but the present understanding is that cholesterol metabolism in the brain is independent from that in peripheral tissues. Lipoprotein receptors from the LDL receptor family (LRPs) have key roles in lipid particle accumulation in cells involved in vascular and cardiac pathophysiology; however, their function on neural cells is unknown. METHODS AND RESULTS: The expression of LRP5 and the components and targets of its downstream signalling pathway, the canonical Wnt pathway, including ß-catenin, LEF1, VEGF, OPN, MMP7, and ADAM10, is analysed in the brains of Wt and Lrp5-/- mice and in a neuroblastoma cell line. LRP5 expression is increased in a time- and dose-dependent manner after lipid loading in neuronal cells; however, it does not participate in cholesterol homeostasis as shown by intracellular lipid accumulation analyses. Neurons challenged with staurosporin and H2O2 display an anti-apoptotic protective role for LRP5. CONCLUSIONS: For the first time, it has been shown that neurons can accumulate intracellular lipids and lipid uptake is performed mainly by the LDLR, while CD36, LRP1, and LRP5 do not play a major role. In addition, it has been shown that LRP5 triggers the canonical Wnt pathway in neuronal cells to generate pro-survival signals. Finally, Lrp5-/- mice have maintained expression of LRP5 only in the brain supporting the biological plausible concept of the need of brain LRP5 to elicit pro-survival processes and embryonic viability.
Assuntos
Hipercolesterolemia , Via de Sinalização Wnt , Animais , Camundongos , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Peróxido de Hidrogênio , Receptores de LDL , Colesterol , beta Catenina/metabolismo , Homeostase , Neurônios/metabolismoRESUMO
BACKGROUND: Familial exudative vitreoretinopathy (FEVR) is a genetic eye disorder that leads to abnormal development of retinal blood vessels, resulting in vision impairment. This study aims to identify pathogenic variants by targeted exome sequencing in 9 independent pedigrees with FEVR and characterize the novel pathogenic variants by molecular dynamics simulation. METHODS: Clinical data were collected from 9 families with FEVR. The causative genes were screened by targeted next-generation sequencing (TGS) and verified by Sanger sequencing. In silico analyses (SIFT, Polyphen2, Revel, MutationTaster, and GERP + +) were carried out to evaluate the pathogenicity of the variants. Molecular dynamics was simulated to predict protein conformation and flexibility transformation alterations on pathogenesis. Furthermore, molecular docking techniques were employed to explore the interactions and binding properties between LRP5 and DKK1 proteins relevant to the disease. RESULTS: A 44% overall detection rate was achieved with four variants including c.4289delC: p.Pro1431Argfs*8, c.2073G > T: p.Trp691Cys, c.1801G > A: p.Gly601Arg in LRP5 and c.633 T > A: p.Tyr211* in TSPAN12 in 4 unrelated probands. Based on in silico analysis and ACMG standard, two of them, c.4289delC: p.Pro1431Argfs*8 and c.2073G > T: p.Trp691Cys of LRP5 were identified as novel pathogenic variants. Based on computational predictions using molecular dynamics simulations and molecular docking, there are indications that these two variants might lead to alterations in the secondary structure and spatial conformation of the protein, potentially impacting its rigidity and flexibility. Furthermore, these pathogenic variants are speculated to potentially influence hydrogen bonding interactions and could result in an increased binding affinity with the DKK1 protein. CONCLUSIONS: Two novel genetic variants of the LRP5 gene were identified, expanding the range of mutations associated with FEVR. Through molecular dynamics simulations and molecular docking, the potential impact of these variants on protein structure and their interactions with the DKK1 protein has been explored. These findings provide further support for the involvement of these variants in the pathogenesis of the disease.
Assuntos
Oftalmopatias Hereditárias , Doenças Retinianas , Humanos , Vitreorretinopatias Exsudativas Familiares , Doenças Retinianas/genética , Doenças Retinianas/metabolismo , Simulação de Acoplamento Molecular , Oftalmopatias Hereditárias/genética , Tetraspaninas/genética , Análise Mutacional de DNA , Mutação , Linhagem , Fenótipo , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismoRESUMO
Some studies suggest that the trace element selenium protects against colorectal cancer (CRC). However, the contribution of selenoprotein P (SELENOP), a unique selenocysteine-containing protein, to sporadic colorectal carcinogenesis challenges this paradigm. SELENOP is predominately secreted by the liver but is also expressed in various cells of the small intestine and colon in mice and humans. In this issue of the JCI, Pilat et al. demonstrate that increased SELENOP expression promoted the progression of conventional adenomas to carcinoma. SELENOP functioned as a modulator of canonical WNT signaling activity through interactions with WNT3A and its coreceptor LDL receptor-related protein 5/6 (LRP5/6). Secreted SELENOP formed a concentration gradient along the gut crypt axis, which might amplify WNT signaling activity by binding to LRPL5/6. The mechanism for WNT control via SELENOP may affect colorectal tumorigenesis and provide therapeutic targets for CRC.
Assuntos
Neoplasias Colorretais , Selênio , Humanos , Camundongos , Animais , Selenoproteína P/genética , Selenoproteína P/metabolismo , Carcinogênese/genética , Carcinogênese/metabolismo , Fígado/metabolismo , Transformação Celular Neoplásica/metabolismo , Selênio/metabolismo , Neoplasias Colorretais/genética , Neoplasias Colorretais/metabolismo , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteína Wnt3A/genética , Proteína Wnt3A/metabolismoRESUMO
BACKGROUND AND OBJECTIVE: Mutations in low-density lipoprotein receptor-related protein 5 (LRP5) cause various bone diseases. Several mouse models were generated to study the role of LRP5 in bone development. But most of the studies were confined to the appendicular skeleton. The role of LRP5 in the axial skeleton, especially in the craniofacial skeleton, is largely unknown. The aim of this study was to investigate the craniofacial phenotype with the LRP5G171V mutation. METHODS: To understand how LRP5 affects craniofacial bone properties, we analyzed LRP5 high-bone-mass mutant mice carrying the G171V missense mutation (LRP5HBM ). Quantitative microcomputed tomographic imaging and histomorphometric analyses were used to study craniofacial phenotypes and bone density. Histology, immunohistochemistry, and in vivo fluorochrome labeling were used to study molecular mechanisms. RESULTS: LRP5HBM mice showed overall minor changes in the craniofacial bone development but with increased bone mass in the interradicular alveolar bone, edentulous ridge, palatine bone, and premaxillary suture. Elevated osteocyte density was observed in LRP5HBM mice, along with increased Runx2 expression and unmineralized bone surrounding osteocytes. Meanwhile, LRP5HBM mice exhibited increased osteoprogenitors, but no significant changes were observed in osteoclasts. This led to a high-bone-mass phenotype, and an increased osteocyte density in the alveolar bone and edentulous ridge. CONCLUSION: LRP5HBM mice display increased bone mass in the alveolar bone with minor changes in the craniofacial morphology. Collectively, these data elucidated the important role of LRP5 in axial bone development and homeostasis and provided clues into the therapeutical potential of LRP5 signaling in treating alveolar bone loss.
Assuntos
Osso e Ossos , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Camundongos , Animais , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Osso e Ossos/metabolismo , Mutação/genética , Densidade Óssea/genética , Osteoclastos/metabolismoRESUMO
Although selenium deficiency correlates with colorectal cancer (CRC) risk, the roles of the selenium-rich antioxidant selenoprotein P (SELENOP) in CRC remain unclear. In this study, we defined SELENOP's contributions to sporadic CRC. In human single-cell cRNA-Seq (scRNA-Seq) data sets, we discovered that SELENOP expression rose as normal colon stem cells transformed into adenomas that progressed into carcinomas. We next examined the effects of Selenop KO in a mouse adenoma model that involved conditional, intestinal epithelium-specific deletion of the tumor suppressor adenomatous polyposis coli (Apc) and found that Selenop KO decreased colon tumor incidence and size. We mechanistically interrogated SELENOP-driven phenotypes in tumor organoids as well as in CRC and noncancer cell lines. Selenop-KO tumor organoids demonstrated defects in organoid formation and decreases in WNT target gene expression, which could be reversed by SELENOP restoration. Moreover, SELENOP increased canonical WNT signaling activity in noncancer and CRC cell lines. In defining the mechanism of action of SELENOP, we mapped protein-protein interactions between SELENOP and the WNT coreceptors low-density lipoprotein receptor-related proteins 5 and 6 (LRP5/6). Last, we confirmed that SELENOP-LRP5/6 interactions contributed to the effects of SELENOP on WNT activity. Overall, our results position SELENOP as a modulator of the WNT signaling pathway in sporadic CRC.
Assuntos
Adenoma , Neoplasias Colorretais , Selênio , Camundongos , Animais , Humanos , Via de Sinalização Wnt , Selenoproteína P/genética , Selenoproteína P/metabolismo , Neoplasias Colorretais/patologia , Selênio/metabolismo , Carcinogênese/genética , Adenoma/metabolismo , Regulação Neoplásica da Expressão Gênica , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismoRESUMO
INTRODUCTION: The low-density lipoprotein receptor-related protein 5 (LRP5) and its inhibitor sclerostin, are key components of bone metabolism and potential contributors to type 2 diabetes mellitus susceptibility. This study aims at evaluating the expression of placental LRP5 and sclerostin in pregnancies with gestational diabetes mellitus (GDM) and investigate possible associations with umbilical sclerostin concentrations and clinical outcomes in mothers and their neonates. METHODS: Twenty-six GDM-mothers and 34 non-GDM mothers of Caucasian origin and their neonates admitted in a gynecology and obstetrics department of a university hospital were included in this study. Demographic data and maternal fasting glucose concentrations (24-28 weeks of gestation) were retrieved from the patients' medical records. Placental LRP5 was determined by immunohistochemistry (IHC) and Western blotting analysis; placental sclerostin was determined by IHC. Umbilical serum sclerostin concentrations were measured by ELISA. RESULTS: Placental sclerostin IHC intensity values were positively correlated with LRP5 values as detected either by IHC (r = 0.529; P < .001) or Western blotting (r = 0.398; P = .008), with pregestational maternal body mass index values (r = 0.299; P = .043) and with maternal fasting glucose concentrations (r = 0.475; P = .009). Placental sclerostin and LRP5 were significantly greater in GDM compared with non-GDM placentas (histo-score: 65.08 ± 17.09 vs 11.45 ± 2.33, P < .001; 145.53 ± 43.74 vs 202.88 ± 58.65, P < .001; respectively). DISCUSSION: Sclerostin and LRP5 were detected in human placentas. The overexpression of placental sclerostin and LRP5 values in GDM compared with non-GDM pregnancies, as well as the positive association of placental sclerostin values with pregestational maternal body mass index and maternal fasting glucose concentrations may indicate the development of an adaptive mechanism in face of maternal hyperglycemia.
Assuntos
Diabetes Mellitus Tipo 2 , Diabetes Gestacional , Feminino , Humanos , Recém-Nascido , Gravidez , Diabetes Mellitus Tipo 2/metabolismo , Glucose/metabolismo , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Placenta/metabolismoRESUMO
WNT signaling, essential for many aspects of development, is among the most commonly altered pathways associated with human disease. While initially studied in cancer, dysregulation of WNT signaling has been determined to be essential for skeletal development and the maintenance of bone health throughout life. In this review, we discuss the role of Wnt signaling in bone development and disease with a particular focus on two areas. First, we discuss the roles of WNT signaling pathways in skeletal development, with an emphasis on congenital and idiopathic skeletal syndromes and diseases that are associated with genetic variations in WNT signaling components. Next, we cover a topic that has long been an interest of our laboratory, how high and low levels of WNT signaling affects the establishment and maintenance of healthy bone mass. We conclude with a discussion of the status of WNT-based therapeutics in the treatment of skeletal disease.
Assuntos
Densidade Óssea , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade , Humanos , Densidade Óssea/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Osso e Ossos/metabolismo , Via de Sinalização Wnt , Desenvolvimento ÓsseoRESUMO
Diabetes and metabolic perturbation are global health challenges. Sleep insufficiency may trigger metabolic dysregulation leading to diabetes. However, the intergenerational transmission of this environmental information is not clearly understood. The research objective was to determine the possible effect of paternal sleep deprivation on the metabolic phenotype of the offspring and to investigate the underlying mechanism of epigenetic inheritance. Male offspring of sleep-deprived fathers exhibit glucose intolerance, insulin resistance, and impaired insulin secretion. In these SD-F1 offspring, a reduction in beta cell mass and proliferation of beta cells were observed. Mechanistically, in pancreatic islets of SD-F1 offspring, we identified alterations in DNA methylation at the promoter region of the LRP5 (LDL receptor related protein 5) gene, a coreceptor of Wnt signaling, resulting in downregulation of downstream effectors cyclin D1, cyclin D2, and Ctnnb1. Restoration of Lrp5 in the pancreas of SD-F1 male mice could improve impaired glucose tolerance and expression of cyclin D1, cyclin D2, and Ctnnb1. This study might significantly contribute to our understanding of the effects of sleeplessness on health and metabolic disease risk from the perspective of the heritable epigenome.
Assuntos
Diabetes Mellitus , Intolerância à Glucose , Ilhotas Pancreáticas , Melatonina , Masculino , Camundongos , Animais , Humanos , Metilação de DNA , Privação do Sono , Ciclina D1/genética , Ciclina D1/metabolismo , Ciclina D1/farmacologia , Ciclina D2/genética , Ciclina D2/metabolismo , Ciclina D2/farmacologia , Melatonina/farmacologia , Ilhotas Pancreáticas/metabolismo , Pai , Diabetes Mellitus/genética , Diabetes Mellitus/metabolismo , Intolerância à Glucose/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismoRESUMO
BACKGROUND AND STUDY AIMS: Intestinal metaplasia (IM), and Helicobacter pylori (HP) infection can be shown as risk factors in the development of gastric cancer (GC). WNT signaling pathway plays a critical role in carcinogenesis. However, the literature studies are limited on the significance of this pathway for the transition from IM to GC. PATIENTS AND METHODS: We aimed to investigate the importance of the genes of WNT signaling pathways diagnostic and prognostic markers in the presence and absence of HP in conversion from IM to GC. 104 patients, (GC group n = 35, IM group n = 45, control group n = 25) were included in this case-control study. Expression of genes in WNT signalling were searched in study groups with qRT-PCR array and qRT-PCR method. Data were analysed using PCR array data analysis software. RESULTS: Statistically significant overexpression of RHOA, CSNK1A1, DVL2, FZD8 and LRP5 genes was detected in the GC and IM groups compared to the control group (p < 0.05). Statistically significant overexpression of RHOA, CSNK1A1, DVL2, FZD8 and LRP5 genes was observed in patients with metastatic GC compared to patients with GC without metastasis (p < 0.05). It was found that the RHOA, CSNK1A1, DVL2, FZD8 and LRP5 genes were statistically significantly over-expressed in diffuse GC patients compared to non-diffuse GC patients (p < 0.05). Statistically significant overexpression of RHOA, CSNK1A1, DVL2, FZD8 and LRP5 genes was detected in HP positive IM patients compared to HP negative IM patients (p < 0.05). CONCLUSION: Overexpression of RHOA, CSNK1A1, DVL2, FZD8 and LRP5 genes in IM may suggest that these genes are important markers in the development of IM and inflammation with HP. In addition, these genes are linked to tumor burden in the GC group. Consequently, we can conclude that these genes are poor prognosis biomarkers for GC and have the potential to be used as markers for future treatment monitoring.
Assuntos
Infecções por Helicobacter , Helicobacter pylori , Neoplasias Gástricas , Humanos , Neoplasias Gástricas/patologia , Mucosa Gástrica/metabolismo , Estudos de Casos e Controles , Fatores de Risco , Infecções por Helicobacter/complicações , Infecções por Helicobacter/genética , Proteína rhoA de Ligação ao GTP/genética , Proteína rhoA de Ligação ao GTP/metabolismo , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteínas Desgrenhadas/metabolismoRESUMO
Osteoporosis is a highly prevalent disease characterized by bone mass loss and structural deterioration. There are evidences that altered differentiation of human bone marrow mesenchymal stromal/stem cells (hBMSCs) is a major cause for osteoporosis. Recent studies suggest that circular RNAs (circRNAs) are dysregulated in osteoporosis patients and involved in the pathogenesis of osteoporosis. In the present study, we are aimed to analyze the circRNA expression profiles in osteoporosis patients and identify potential circRNAs that involved in the differentiation of hBMSCs during osteoporosis. Transcriptome RNA-sequencing was conducted to search for differentially expressed circRNAs. Transwell assay, ARS and ALP staining, and ectopic bone formation model were performed to evaluate osteogenic differentiation of hBMSCs. RNA pull-down assay, RNA immunoprecipitation, western blot, and in vitro binding assay were conducted to evaluate the interaction of circRNAs and RNA-binding protein HuR. We found that hsa_circ_0008842 (designated as circZNF367) was upregulated in osteoporosis patients and decreased in hBMSCs during osteogenic differentiation. CircZNF367 overexpression suppressed migration, invasion and osteogenic differentiation of hBMSCs in vitro and in vivo. In comparison, knockdown of circZNF367 promoted migration, invasion and osteogenic differentiation of hBMSCs. CircZNF367 could interact with the RNA-binding protein HuR, thus reduced the mRNA stability of LRP5. Furthermore, HuR overexpression or LRP5 restoration abrogated the effects of circZNF367 overexpression on osteogenic differentiation of hBMSCs. Our results indicated that circZNF367 played a role in osteogenic differentiation of hBMSCs via reducing HuR-mediated mRNA stability of LRP5.
Assuntos
Células-Tronco Mesenquimais , MicroRNAs , Osteoporose , Humanos , MicroRNAs/genética , Osteogênese/genética , RNA Circular/genética , RNA Circular/metabolismo , Medula Óssea/metabolismo , Células Cultivadas , Diferenciação Celular/genética , Osteoporose/genética , Osteoporose/patologia , Células da Medula Óssea/metabolismo , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismoRESUMO
Canonical Wnt signaling is involved in skeletal muscle cell biology. The exact way in which this pathway exerts its contribution to myogenesis or neuromuscular junctions (NMJ) is a matter of debate. Next to the common co-receptors of canonical Wnt signaling, Lrp5 and Lrp6, the receptor tyrosine kinase MuSK was reported to bind at NMJs WNT glycoproteins by its extracellular cysteine-rich domain. Previously, we reported canonical Wnt signaling being active in fast muscle fiber types. Here, we used conditional Lrp5 or Lrp6 knockout mice to investigate the role of these receptors in muscle cells. Conditional double knockout mice died around E13 likely due to ectopic expression of the Cre recombinase. Phenotypes of single conditional knockout mice point to a very divergent role for the two receptors. First, muscle fiber type distribution and size were changed. Second, canonical Wnt signaling reporter mice suggested less signaling activity in the absence of Lrps. Third, expression of several myogenic marker genes was changed. Fourth, NMJs were of fragmented phenotype. Fifth, recordings revealed impaired neuromuscular transmission. In sum, our data show fundamental differences in absence of each of the Lrp co-receptors and suggest a differentiated view of canonical Wnt signaling pathway involvement in adult skeletal muscle cells.
Assuntos
Fibras Musculares Esqueléticas , Músculo Esquelético , Junção Neuromuscular , Receptores Wnt , Animais , Camundongos , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-5 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/genética , Proteína-6 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Camundongos Knockout , Músculo Esquelético/metabolismo , Junção Neuromuscular/genética , Junção Neuromuscular/metabolismo , Via de Sinalização Wnt/genética , Via de Sinalização Wnt/fisiologia , Receptores Wnt/genética , Receptores Wnt/metabolismo , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/metabolismoRESUMO
The present study was performed to evaluate the association of WNT signaling pathway genes variants with pulmonary tuberculosis (PTB) risk in Chinese Han population. Our study subjects were composed of 452 PTB patients and 465 normal controls, and seventeen SNPs of seven genes in WNT signaling pathway (SFRP1, WNT3A, CTNNB1, WIF-1, DKK-1, LRP5, LRP6) were genotyped by SNPscan technique. We found no significant relationship of SFRP1 rs10088390, rs4736958, rs3242, WNT3A rs752107, rs3121310, CTNNB1 rs2293303, rs1798802, rs4135385, WIF-1 rs1026024, rs3782499, DKK-1 rs2241529, rs1569198, LRP5 rs3736228, rs556442, LRP6 rs2302685, rs11054697, rs10743980 polymorphisms with PTB susceptibility. While, WIF-1 rs3782499 variant was associated with susceptibility to PTB under recessive model, and haplotype analysis showed that DKK-1 GA haplotype frequency was significantly increased in PTB patients. The WNT3A rs3121310, CTNNB1 rs2293303 polymorphisms were respectively associated with drug-induced liver injury (DILI), sputum smear-positive in PTB patients. The rs3782499 in WIF-1 gene was related to fever, leukopenia, and the rs1569198 in DKK-1 was linked to sputum smear-positive in PTB patients. In LRP5 gene, rs3736228, rs556442 variants respectively affected the occurrence of DILI, fever, and LRP6 gene rs2302685, rs10743980 variants respectively influenced the development of hypoproteinemia, sputum smear-positive in PTB patients. Our results revealed that WNT signaling pathway genes variation were not associated with the susceptibility to PTB, while WNT3A, CTNNB1, WIF-1, DKK-1, LRP5, LRP6 genetic variations might be closely related to the occurrence of several clinical characteristics of PTB patients.