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1.
J Cell Biochem ; 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38747370

RESUMO

Lipid droplets are organelles with unique spherical structures. They consist of a hydrophobic neutral lipid core that varies depending on the cell type and tissue. These droplets are surrounded by phospholipid monolayers, along with heterogeneous proteins responsible for neutral lipid synthesis and metabolism. Additionally, there are specialized lipid droplet-associated surface proteins. Recent evidence suggests that proteins from the perilipin family (PLIN) are associated with the surface of lipid droplets and are involved in their formation. These proteins have specific roles in hepatic lipid droplet metabolism, such as protecting the lipid droplets from lipase action and maintaining a balance between lipid storage and utilization in specific cells. Metabolic dysfunction-associated steatotic liver disease (MASLD) is characterized by the accumulation of lipid droplets in more than 5% of the hepatocytes. This accumulation can progress into metabolic dysfunction-associated steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. The accumulation of hepatic lipid droplets in the liver is associated with the progression of MASLD and other diseases such as sarcopenic obesity. Therefore, it is crucial to understand the role of perilipins in this accumulation, as these proteins are key targets for developing novel therapeutic strategies. This comprehensive review aims to summarize the structure and characteristics of PLIN proteins, as well as their pathogenic role in the development of hepatic steatosis and fatty liver diseases.

2.
Int J Mol Sci ; 25(8)2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38673873

RESUMO

The lipocalin proteins are a large family of small extracellular proteins that demonstrate significant heterogeneity in sequence similarity and have highly conserved crystal structures. They have a variety of functions, including acting as carrier proteins, transporting retinol, participating in olfaction, and synthesizing prostaglandins. Importantly, they also play a critical role in human diseases, including cancer. Additionally, they are involved in regulating cellular homeostasis and immune response and dispensing various compounds. This comprehensive review provides information on the lipocalin family, including their structure, functions, and implications in various diseases. It focuses on selective important human lipocalin proteins, such as lipocalin 2 (LCN2), retinol binding protein 4 (RBP4), prostaglandin D2 synthase (PTGDS), and α1-microglobulin (A1M).


Assuntos
Oxirredutases Intramoleculares , Lipocalinas , Humanos , Lipocalinas/metabolismo , Lipocalinas/química , Lipocalinas/genética , Neoplasias/metabolismo , Relação Estrutura-Atividade , Animais
3.
Cells ; 13(7)2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38606998

RESUMO

Nasopharyngeal carcinoma (NPC) is a type of cancer that originates from the mucosal lining of the nasopharynx and can invade and spread. Although contemporary chemoradiotherapy effectively manages the disease locally, there are still challenges with locoregional recurrence and distant failure. Therefore, it is crucial to have a deeper understanding of the molecular basis of NPC cell movement in order to develop a more effective treatment and to improve patient survival rates. Cancer cell line models are invaluable in studying health and disease and it is not surprising that they play a critical role in NPC research. Consequently, scientists have established around 80 immortalized human NPC lines that are commonly used as in vitro models. However, over the years, it has been observed that many cell lines are misidentified or contaminated by other cells. This cross-contamination leads to the creation of false cell lines that no longer match the original donor. In this commentary, we discuss the impact of misidentified NPC cell lines on the scientific literature. We found 1159 articles from 2000 to 2023 that used NPC cell lines contaminated with HeLa cells. Alarmingly, the number of publications and citations using these contaminated cell lines continued to increase, even after information about the contamination was officially published. These articles were most commonly published in the fields of oncology, pharmacology, and experimental medicine research. These findings highlight the importance of science policy and support the need for journals to require authentication testing before publication.


Assuntos
Neoplasias Nasofaríngeas , Humanos , Carcinoma Nasofaríngeo/metabolismo , Células HeLa , Neoplasias Nasofaríngeas/metabolismo , Linhagem Celular Tumoral , Recidiva Local de Neoplasia/metabolismo , Nasofaringe/metabolismo , Nasofaringe/patologia
5.
Front Endocrinol (Lausanne) ; 15: 1365602, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38645429

RESUMO

The 25 kDa-sized protein Lipocalin 2 (LCN2) was originally isolated from human neutrophil granulocytes more than 30 years ago. LCN2 is an emerging player in innate immune defense, as it reduces bacterial growth due to its ability to sequester iron-containing bacterial siderophores. On the other hand, LCN2 also serves as a transporter for various hydrophobic substances due to its ß-barrel shaped structure. Over the years, LCN2 has been detected in many other cell types including epithelial cells, astrocytes, and hepatocytes. Studies have clearly shown that aberrant expression of LCN2 is associated with a variety of disorders and malignancies, including several diseases of the reproductive system. Furthermore, LCN2 was proposed as a non-invasive prognostic and/or diagnostic biomarker in this context. Although several studies have shed light on the role of LCN2 in various disorders of the female and male reproductive systems, including tumorigenesis, a comprehensive understanding of the physiological function of LCN2 in the reproductive tract is still lacking. However, there is evidence that LCN2 is directly related to fertility, as global depletion of Lcn2 in mice has a negative effect on their pregnancy rate. Since LCN2 expression can be regulated by steroid hormones, it is not surprising that its expression fluctuates greatly during remodeling processes in the female reproductive tract, especially in the uterus. Well-founded details about the expression and regulation of LCN2 in a healthy reproductive state and also about possible changes during reproductive aging could contribute to a better understanding of LCN2 as a target in various diseases. Therefore, the present review summarizes current knowledge about LCN2 in the reproductive system, including studies in rodents and humans, and discusses changes in LCN2 expression during pathological events. The limited data suggest that LCN2 is expressed and regulated differently in healthy male and female reproductive organs.


Assuntos
Lipocalina-2 , Humanos , Lipocalina-2/metabolismo , Lipocalina-2/genética , Animais , Feminino , Masculino , Reprodução/fisiologia , Genitália/metabolismo
6.
Bone Rep ; 21: 101759, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38590391

RESUMO

Patients with Crohn's disease are at increased risk for symptomatic nephrolithiasis. Stones in these patients are most commonly composed of calcium oxalate monohydrate or mixed calcium-oxalate and calcium-phosphate. Precipitation of both minerals depends on urinary pH, calcium, phosphate and oxalate excretion. The present manuscript reports on two patients with Crohn's disease and bowel resection, in whom the onset of symptomatic urolithiasis occurred after repeated infusions of ferric carboxymaltose - a drug, which is known to cause hyperphosphaturia. The present study shows that ferric carboxymaltose-induced hyperphosphaturia can be associated with kidney stone formation and symptomatic urolithiasis, especially in patients treated with calcitriol. Calcitriol has been shown to mitigate ferric carboxymaltose-induced secondary hyperparathyroidism and hyperphosphaturia, but is known to increase urinary calcium excretion. Chemical analysis of recovered stones revealed that they were mixed calcium oxalate and phosphate stones. Ring-like deposition of iron detected by spatially resolved elemental analysis using laser ablation-inductively coupled plasma mass spectrometry, showed that the stones also contained iron. Based on our findings, we propose that patients with inflammatory bowel disease requiring intravenous iron therapy should be carefully monitored for the development of hypophosphatemia and urolithiasis. If hypophosphatemia occurs in such patients, calcitriol should be used with caution.

7.
Mol Oncol ; 2024 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-38429970

RESUMO

The effect of grainyhead-like transcription factor 3 (GRHL3) on cancer development depends on the cancer subtypes as shown in tumor entities such as colorectal or oral squamous cell carcinomas. Here, we analyzed the subtype-specific role of GRHL3 in bladder carcinogenesis, comparing common urothelial carcinoma (UC) with squamous bladder cancer (sq-BLCA). We examined GRHL3 mRNA and protein expression in cohorts of patient samples, its prognostic role and its functional impact on tumorigeneses in different molecular and histopathological subtypes of bladder cancer. We showed for GRHL3 a reverse expression in squamous and urothelial bladder cancer subtypes. Stably GRHL3-overexpressing EJ28, J82, and SCaBER in vitro models revealed a tumor-suppressive function in squamous and an oncogenic role in the urothelial cancer cells affecting cell and colony growth, and migratory and invasive capacities. Transcriptomic profiling demonstrated highly subtype-specific GRHL3-regulated expression networks coined by the enrichment of genes involved in integrin-mediated pathways. In SCaBER, loss of ras homolog family member A (RHOA) GTPase activity was demonstrated to be associated with co-regulation of eukaryotic translation initiation factor 4E family member 3 (EIF4E3), a potential tumor suppressor gene. Thus, our data provide for the first time a detailed insight into the role of the transcription factor GRHL3 in different histopathological subtypes of bladder cancer.

8.
Front Endocrinol (Lausanne) ; 15: 1325386, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38464972

RESUMO

Introduction: Estrogens are crucial regulators of ovarian function, mediating their signaling through binding to estrogen receptors. The disruption of the estrogen receptor 1 (Esr1) provokes infertility associated with a hemorrhagic, cystic phenotype similar to that seen in diseased or aged ovaries. Our previous study indicated the possibility of altered iron metabolism in Esr1-deficient ovaries showing massive expression of lipocalin 2, a regulator of iron homeostasis. Methods: Therefore, we examined the consequences of depleting Esr1 in mouse ovaries, focusing on iron metabolism. For that reason, we compared ovaries of adult Esr1-deficient animals and age-matched wild type littermates. Results and discussion: We found increased iron accumulation in Esr1-deficient animals by using laser ablation inductively coupled plasma mass spectrometry. Western blot analysis and RT-qPCR confirmed that iron overload alters iron transport, storage and regulation. In addition, trivalent iron deposits in form of hemosiderin were detected in Esr1-deficient ovarian stroma. The depletion of Esr1 was further associated with an aberrant immune cell landscape characterized by the appearance of macrophage-derived multinucleated giant cells (MNGCs) and increased quantities of macrophages, particularly M2-like macrophages. Similar to reproductively aged animals, MNGCs in Esr1-deficient ovaries were characterized by iron accumulation and strong autofluorescence. Finally, deletion of Esr1 led to a significant increase in ovarian mast cells, involved in iron-mediated foam cell formation. Given that these findings are characteristics of ovarian aging, our data suggest that Esr1 deficiency triggers mechanisms similar to those associated with aging.


Assuntos
Cistos , Sobrecarga de Ferro , Feminino , Camundongos , Animais , Ovário/metabolismo , Receptor alfa de Estrogênio/metabolismo , Camundongos Knockout , Sobrecarga de Ferro/genética , Ferro
9.
Adv Sci (Weinh) ; 11(18): e2307734, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38430535

RESUMO

The hepatic content of amyloid beta (Aß) decreases drastically in human and rodent cirrhosis highlighting the importance of understanding the consequences of Aß deficiency in the liver. This is especially relevant in view of recent advances in anti-Aß therapies for Alzheimer's disease (AD). Here, it is shown that partial hepatic loss of Aß in transgenic AD mice immunized with Aß antibody 3D6 and its absence in amyloid precursor protein (APP) knockout mice (APP-KO), as well as in human liver spheroids with APP knockdown upregulates classical hallmarks of fibrosis, smooth muscle alpha-actin, and collagen type I. Aß absence in APP-KO and deficiency in immunized mice lead to strong activation of transforming growth factor-ß (TGFß), alpha secretases, NOTCH pathway, inflammation, decreased permeability of liver sinusoids, and epithelial-mesenchymal transition. Inversely, increased systemic and intrahepatic levels of Aß42 in transgenic AD mice and neprilysin inhibitor LBQ657-treated wild-type mice protect the liver against carbon tetrachloride (CCl4)-induced injury. Transcriptomic analysis of CCl4-treated transgenic AD mouse livers uncovers the regulatory effects of Aß42 on mitochondrial function, lipid metabolism, and its onco-suppressive effects accompanied by reduced synthesis of extracellular matrix proteins. Combined, these data reveal Aß as an indispensable regulator of cell-cell interactions in healthy liver and a powerful protector against liver fibrosis.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Modelos Animais de Doenças , Fígado , Camundongos Transgênicos , Animais , Camundongos , Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/genética , Fígado/metabolismo , Fígado/patologia , Doença de Alzheimer/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Humanos , Camundongos Knockout , Camundongos Endogâmicos C57BL
10.
Cell Death Discov ; 10(1): 94, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38388533

RESUMO

The molecular mechanisms underlying the transition from nonalcoholic fatty liver disease (NAFLD) to hepatocellular carcinoma (HCC) are incompletely understood. During the development of NAFLD, Perilipin 5 (PLIN5) can regulate lipid metabolism by suppressing lipolysis and preventing lipotoxicity. Other reports suggest that the lack of PLIN5 decreases hepatic injury, indicating a protective role in NAFLD pathology. To better understand the role of PLIN5 in liver disease, we established mouse models of NAFLD and NAFLD-induced HCC, in which wild-type and Plin5 null mice were exposed to a single dose of acetone or 7,12-dimethylbenz[a]anthracene (DMBA) in acetone, followed by a 30-week high-fat diet supplemented with glucose/fructose. In the NAFLD model, RNA-seq revealed significant changes in genes related to lipid metabolism and immune response. At the intermediate level, pathways such as AMP-activated protein kinase (AMPK), signal transducer and activator of transcription 3 (STAT3), c-Jun N-terminal kinase (JNK), and protein kinase B (AKT) were blunted in Plin5-deficient mice (Plin5-/-) compared to wild-type mice (WT). In the NAFLD-HCC model, only WT mice developed liver tumors, while Plin5-/- mice were resistant to tumorigenesis. Furthermore, only 32 differentially expressed genes associated with NALFD progession were identified in Plin5 null mice. The markers of mitochondrial function and immune response, such as the peroxisome proliferator-activated receptor-γ, coactivator 1-α (PGC-1α) and phosphorylated STAT3, were decreased. Lipidomic analysis revealed differential levels of some sphingomyelins between WT and Plin5-/- mice. Interestingly, these changes were not detected in the HCC model, indicating a possible shift in the metabolism of sphingomelins during carcinogenesis.

11.
Int J Mol Sci ; 25(3)2024 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-38339160

RESUMO

Obesity or excessive weight gain is identified as the most important and significant risk factor in the development and progression of type 2 diabetes mellitus (DM) in all age groups. It has reached pandemic dimensions, making the treatment of obesity crucial in the prevention and management of type 2 DM worldwide. Multiple clinical studies have demonstrated that moderate and sustained weight loss can improve blood glucose levels, insulin action and reduce the need for diabetic medications. A combined approach of diet, exercise and lifestyle modifications can successfully reduce obesity and subsequently ameliorate the ill effects and deadly complications of DM. This approach also helps largely in the prevention, control and remission of DM. Obesity and DM are chronic diseases that are increasing globally, requiring new approaches to manage and prevent diabetes in obese individuals. Therefore, it is essential to understand the mechanistic link between the two and design a comprehensive approach to increase life expectancy and improve the quality of life in patients with type 2 DM and obesity. This literature review provides explicit information on the clinical definitions of obesity and type 2 DM, the incidence and prevalence of type 2 DM in obese individuals, the indispensable role of obesity in the pathophysiology of type 2 DM and their mechanistic link. It also discusses clinical studies and outlines the recent management approaches for the treatment of these associated conditions. Additionally, in vivo studies on obesity and type 2 DM are discussed here as they pave the way for more rigorous development of therapeutic approaches.


Assuntos
Diabetes Mellitus Tipo 2 , Humanos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Qualidade de Vida , Obesidade/complicações , Obesidade/epidemiologia , Obesidade/terapia , Fatores de Risco , Redução de Peso
12.
Diagnostics (Basel) ; 14(4)2024 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-38396409

RESUMO

Semaphorin 4D (Sema4D), also known as CD100, is a multifunctional transmembrane protein with immunoregulatory functions. Upon the activation of immune cells, soluble Semaphorin 4D (sSema4D) is proteolytically cleaved from the membrane by metalloproteinases. sSema4D levels are elevated in various (auto-)inflammatory diseases. Our aim was to investigate sSema4D levels in association with sepsis and critical illnesses and to evaluate sSema4D's potential as a prognostic biomarker. We measured sSema4D levels in 192 patients upon admission to our medical intensive care unit. We found similar levels of sSema4D in 125 patients with sepsis compared to 67 non-septic patients. sSema4D levels correlated with leukocytes but not with other markers of systemic inflammation such as C-reactive protein or procalcitonin. Most interestingly, in a subgroup of patients suffering from pre-existing liver cirrhosis, we observed significantly higher levels of sSema4D. Consistently, sSema4D was also positively correlated with markers of hepatic and cholestatic injury. Our study suggests that sSema4D is not regulated in sepsis compared to other causes of critical illness. However, sSema4D seems to be associated with hepatic injury and inflammation.

13.
Int J Mol Sci ; 25(2)2024 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-38256181

RESUMO

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is rapidly increasing worldwide at an alarming pace, due to an increase in obesity, sedentary and unhealthy lifestyles, and unbalanced dietary habits. MASLD is a unique, multi-factorial condition with several phases of progression including steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Sterol element binding protein 1c (SREBP1c) is the main transcription factor involved in regulating hepatic de novo lipogenesis. This transcription factor is synthesized as an inactive precursor, and its proteolytic maturation is initiated in the membrane of the endoplasmic reticulum upon stimulation by insulin. SREBP cleavage activating protein (SCAP) is required as a chaperon protein to escort SREBP from the endoplasmic reticulum and to facilitate the proteolytic release of the N-terminal domain of SREBP into the Golgi. SCAP inhibition prevents activation of SREBP and inhibits the expression of genes involved in triglyceride and fatty acid synthesis, resulting in the inhibition of de novo lipogenesis. In line, previous studies have shown that SCAP inhibition can resolve hepatic steatosis in animal models and intensive research is going on to understand the effects of SCAP in the pathogenesis of human disease. This review focuses on the versatile roles of SCAP/SREBP regulation in de novo lipogenesis and the structure and molecular features of SCAP/SREBP in the progression of hepatic steatosis. In addition, recent studies that attempt to target the SCAP/SREBP axis as a therapeutic option to interfere with MASLD are discussed.


Assuntos
Fígado Gorduroso , Peptídeos e Proteínas de Sinalização Intracelular , Neoplasias Hepáticas , Proteínas de Membrana , Proteína de Ligação a Elemento Regulador de Esterol 1 , Animais , Humanos , Metabolismo dos Lipídeos , Lipogênese , Proteína de Ligação a Elemento Regulador de Esterol 1/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/genética
14.
Commun Biol ; 7(1): 8, 2024 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-38168942

RESUMO

Cholesterol mediates membrane compartmentalization, affecting signaling via differential distribution of receptors and signaling mediators. While excessive cholesterol and aberrant transforming growth factor-ß (TGF-ß) signaling characterize multiple liver diseases, their linkage to canonical vs. non-canonical TGF-ß signaling remained unclear. Here, we subjected murine hepatocytes to cholesterol depletion (CD) or enrichment (CE), followed by biophysical studies on TGF-ß receptor heterocomplex formation, and output to Smad2/3 vs. Akt pathways. Prior to ligand addition, raft-dependent preformed heteromeric receptor complexes were observed. Smad2/3 phosphorylation persisted following CD or CE. CD enhanced phospho-Akt (pAkt) formation by TGF-ß or epidermal growth factor (EGF) at 5 min, while reducing it at later time points. Conversely, pAkt formation by TGF-ß or EGF was inhibited by CE, suggesting a direct effect on the Akt pathway. The modulation of the balance between TGF-ß signaling to Smad2/3 vs. pAkt (by TGF-ß or EGF) has potential implications for hepatic diseases and malignancies.


Assuntos
Hepatopatias , Proteínas Proto-Oncogênicas c-akt , Camundongos , Animais , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fator de Crescimento Epidérmico , Hepatócitos/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Hepatopatias/metabolismo , Colesterol/metabolismo
15.
Pharmacol Ther ; 253: 108563, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38013053

RESUMO

The deposition of extracellular matrix and hyperplasia of connective tissue characterizes chronic liver disease called hepatic fibrosis. Progression of hepatic fibrosis may lead to hepatocellular carcinoma. At this stage, only liver transplantation is a viable option. However, the number of possible liver donors is less than the number of patients needing transplantation. Consequently, alternative cell therapies based on non-stem cells (e.g., fibroblasts, chondrocytes, keratinocytes, and hepatocytes) therapy may be able to postpone hepatic disease, but they are often ineffective. Thus, novel stem cell-based therapeutics might be potentially important cutting-edge approaches for treating liver diseases and reducing patient' suffering. Several signaling pathways provide targets for stem cell interventions. These include pathways such as TGF-ß, STAT3/BCL-2, NADPH oxidase, Raf/MEK/ERK, Notch, and Wnt/ß-catenin. Moreover, mesenchymal stem cells (MSCs) stimulate interleukin (IL)-10, which inhibits T-cells and converts M1 macrophages into M2 macrophages, producing an anti-inflammatory environment. Furthermore, it inhibits the action of CD4+ and CD8+ T cells and reduces the activity of TNF-α and interferon cytokines by enhancing IL-4 synthesis. Consequently, the immunomodulatory and anti-inflammatory capabilities of MSCs make them an attractive therapeutic approach. Importantly, MSCs can inhibit the activation of hepatic stellate cells, causing their apoptosis and subsequent promotion of hepatocyte proliferation, thereby replacing dead hepatocytes and reducing liver fibrosis. This review discusses the multidimensional therapeutic role of stem cells as cell-based therapeutics in liver fibrosis.


Assuntos
Hepatopatias , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais , Humanos , Linfócitos T CD8-Positivos/patologia , Fígado , Hepatopatias/terapia , Cirrose Hepática/patologia , Anti-Inflamatórios
16.
Cell Mol Gastroenterol Hepatol ; 17(4): 567-587, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38154598

RESUMO

BACKGROUND & AIMS: Transforming growth factor-ß1 (TGF-ß1) plays important roles in chronic liver diseases, including metabolic dysfunction-associated steatotic liver disease (MASLD). MASLD involves various biological processes including dysfunctional cholesterol metabolism and contributes to progression to metabolic dysfunction-associated steatohepatitis and hepatocellular carcinoma. However, the reciprocal regulation of TGF-ß1 signaling and cholesterol metabolism in MASLD is yet unknown. METHODS: Changes in transcription of genes associated with cholesterol metabolism were assessed by RNA sequencing of murine hepatocyte cell line (alpha mouse liver 12/AML12) and mouse primary hepatocytes treated with TGF-ß1. Functional assays were performed on AML12 cells (untreated, TGF-ß1 treated, or subjected to cholesterol enrichment [CE] or cholesterol depletion [CD]), and on mice injected with adenovirus-associated virus 8-control/TGF-ß1. RESULTS: TGF-ß1 inhibited messenger RNA expression of several cholesterol metabolism regulatory genes, including rate-limiting enzymes of cholesterol biosynthesis in AML12 cells, mouse primary hepatocytes, and adenovirus-associated virus-TGF-ß1-treated mice. Total cholesterol levels and lipid droplet accumulation in AML12 cells and liver tissue also were reduced upon TGF-ß1 treatment. Smad2/3 phosphorylation after 2 hours of TGF-ß1 treatment persisted after CE or CD and was mildly increased after CD, whereas TGF-ß1-mediated AKT phosphorylation (30 min) was inhibited by CE. Furthermore, CE protected AML12 cells from several effects mediated by 72 hours of incubation with TGF-ß1, including epithelial-mesenchymal transition, actin polymerization, and apoptosis. CD mimicked the outcome of long-term TGF-ß1 administration, an effect that was blocked by an inhibitor of the type I TGF-ß receptor. In addition, the supernatant of CE- or CD-treated AML12 cells inhibited or promoted, respectively, the activation of LX-2 hepatic stellate cells. CONCLUSIONS: TGF-ß1 inhibits cholesterol metabolism whereas cholesterol attenuates TGF-ß1 downstream effects in hepatocytes.


Assuntos
Fígado Gorduroso , Fator de Crescimento Transformador beta1 , Camundongos , Animais , Fator de Crescimento Transformador beta1/metabolismo , Hepatócitos/metabolismo , Células Estreladas do Fígado/patologia , Linhagem Celular , Fígado Gorduroso/metabolismo
18.
Biomedicines ; 11(10)2023 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-37893089

RESUMO

Extracellular vesicles such as exosomes are small-sized, bilayered extracellular biovesicles generated by almost every cell and released into the surrounding body fluids upon the fusion of multivesicular bodies and the plasma membrane. Based on their origin, they are enriched with a variety of biologically active components including proteins, lipids, nucleic acids, cellular metabolites, and many other constituents. They can either attach or fuse with the membrane of a target cell, or alternatively be taking up via endocytosis by a recipient cell. In particular, milk exosomes have been recently shown to be a fundamental factor supporting infant growth, health, and development. In addition, exosomes derived from different cell types have been shown to possess regenerative, immunomodulatory, and anti-inflammatory properties, suggesting that they are a potential therapeutic tool in modulating the pathogenesis of diverse diseases. Therefore, efficient protocols for the isolation of milk exosomes in a high quantity and purity are the basis for establishing clinical applications. Here, we present an easy-to-follow protocol for exosome isolation from bovine and human milk. Electron microscopic analysis and nanoparticle tracking analysis reveal that the protocols allow the isolation of highly enriched fractions of exosomes. The purified exosomes express the typical exosomal protein markers, CD81 and ALIX.

20.
Cell Death Dis ; 14(8): 549, 2023 08 24.
Artigo em Inglês | MEDLINE | ID: mdl-37620309

RESUMO

Hepatocellular carcinoma (HCC) is one of the most severe malignancies with increasing incidence and limited treatment options. Typically, HCC develops during a multistep process involving chronic liver inflammation and liver fibrosis. The latter is characterized by the accumulation of extracellular matrix produced by Hepatic Stellate Cells (HSCs). This process involves cell cycle re-entry and proliferation of normally quiescent HSCs in an ordered sequence that is highly regulated by cyclins and associated cyclin-dependent kinases (CDKs) such as the Cyclin E1 (CCNE1)/CDK2 kinase complex. In the present study, we examined the role of Cyclin E1 (Ccne1) and Cdk2 genes in HSCs for liver fibrogenesis and hepatocarcinogenesis. To this end, we generated conditional knockout mice lacking Ccne1 or Cdk2 specifically in HSCs (Ccne1∆HSC or Cdk2∆HSC). Ccne1∆HSC mice showed significantly reduced liver fibrosis formation and attenuated HSC activation in the carbon tetrachloride (CCl4) model. In a combined model of fibrosis-driven hepatocarcinogenesis, Ccne1∆HSC mice revealed decreased HSC activation even after long-term observation and substantially reduced tumor load in the liver when compared to wild-type controls. Importantly, the deletion of Cdk2 in HSCs also resulted in attenuated liver fibrosis after chronic CCl4 treatment. Single-cell RNA sequencing revealed that only a small fraction of HSCs expressed Ccne1/Cdk2 at a distinct time point after CCl4 treatment. In summary, we provide evidence that Ccne1 expression in a small population of HSCs is sufficient to trigger extensive liver fibrosis and hepatocarcinogenesis in a Cdk2-dependent manner. Thus, HSC-specific targeting of Ccne1 or Cdk2 in patients with liver fibrosis and high risk for HCC development could be therapeutically beneficial.


Assuntos
Carcinoma Hepatocelular , Ciclina E , Cirrose Hepática , Neoplasias Hepáticas , Animais , Camundongos , Carcinogênese/genética , Carcinoma Hepatocelular/genética , Células Estreladas do Fígado , Cirrose Hepática/genética , Neoplasias Hepáticas/genética , Ciclina E/genética
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