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1.
Commun Biol ; 7(1): 458, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38622242

RESUMO

Differentiation of adipose progenitor cells into mature adipocytes entails a dramatic reorganization of the cellular architecture to accommodate lipid storage into cytoplasmic lipid droplets. Lipid droplets occupy most of the adipocyte volume, compressing the nucleus beneath the plasma membrane. How this cellular remodeling affects sub-nuclear structure, including size and number of nucleoli, remains unclear. We describe the morphological remodeling of the nucleus and the nucleolus during in vitro adipogenic differentiation of primary human adipose stem cells. We find that cell cycle arrest elicits a remodeling of nucleolar structure which correlates with a decrease in protein synthesis. Strikingly, triggering cytoskeletal rearrangements mimics the nucleolar remodeling observed during adipogenesis. Our results point to nucleolar remodeling as an active, mechano-regulated mechanism during adipogenic differentiation and demonstrate a key role of the actin cytoskeleton in defining nuclear and nucleolar architecture in differentiating human adipose stem cells.


Assuntos
Adipogenia , Citoesqueleto , Humanos , Células Cultivadas , Citoesqueleto/metabolismo , Adipócitos/metabolismo , Gotículas Lipídicas/metabolismo
2.
Cell Death Dis ; 15(4): 240, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38561354

RESUMO

Abnormal lipid metabolism and lipid accumulation are characteristic hallmarks of renal cell carcinoma (RCC). While there is prior evidence closely linking such lipid accumulation within RCC cells and consequent tumorigenesis, the mechanisms underlying this process remain incompletely understood. In this study, a series of bioinformatics analyses were initially performed by screening RCC databases and gene sets, ultimately leading to the identification of TRIB3 as an oncogene that functions as a central regulator of lipid metabolism. TRIB3 overexpression was observed in both RCC patient tumor tissues and cell lines, and this upregulation was correlated with a worse RCC patient prognosis. When TRIB3 was knocked down, this resulted in a reduction in lipid accumulation and the consequent induction of endoplasmic reticulum (ER) stress-related apoptotic cell death. At the molecular level, interactions between TRIB3 and PLIN2 were found to abrogate TEB4-mediated PLIN2 ubiquitination and consequent degradation, thus maintaining higher PLIN2 expression levels. This simultaneously helps facilitate the accumulation of lipids while preserving ER homeostasis, thus driving accelerated RCC tumor progression. This TRIB3-PLIN2 axis thus represents a promising new target for efforts to treat RCC.


Assuntos
Carcinoma de Células Renais , Neoplasias Renais , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Humanos , Carcinoma de Células Renais/metabolismo , Gotículas Lipídicas/metabolismo , Estresse do Retículo Endoplasmático/genética , Neoplasias Renais/metabolismo , Lipídeos , Proteínas Repressoras/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas de Ciclo Celular/metabolismo , Perilipina-2/genética , Perilipina-2/metabolismo
3.
Nat Commun ; 15(1): 3213, 2024 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-38615060

RESUMO

Oxidative stress-induced lipid accumulation is mediated by lipid droplets (LDs) homeostasis, which sequester vulnerable unsaturated triglycerides into LDs to prevent further peroxidation. Here we identify the upregulation of lipopolysaccharide-binding protein (LBP) and its trafficking through LDs as a mechanism for modulating LD homeostasis in response to oxidative stress. Our results suggest that LBP induces lipid accumulation by controlling lipid-redox homeostasis through its lipid-capture activity, sorting unsaturated triglycerides into LDs. N-acetyl-L-cysteine treatment reduces LBP-mediated triglycerides accumulation by phospholipid/triglycerides competition and Peroxiredoxin 4, a redox state sensor of LBP that regulates the shuttle of LBP from LDs. Furthermore, chronic stress upregulates LBP expression, leading to insulin resistance and obesity. Our findings contribute to the understanding of the role of LBP in regulating LD homeostasis and against cellular peroxidative injury. These insights could inform the development of redox-based therapies for alleviating oxidative stress-induced metabolic dysfunction.


Assuntos
Proteínas de Fase Aguda , Gotículas Lipídicas , Glicoproteínas de Membrana , Proteínas de Fase Aguda/metabolismo , Proteínas de Transporte/metabolismo , Homeostase , Gotículas Lipídicas/metabolismo , Lipopolissacarídeos/metabolismo , Glicoproteínas de Membrana/metabolismo , Estresse Oxidativo/genética , Estresse Oxidativo/fisiologia , Triglicerídeos
4.
J Mater Chem B ; 12(12): 3022-3030, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38426244

RESUMO

Lipid droplets (LDs) are cytoplasmic lipid-rich organelles with important roles in lipid storage and metabolism, cell signaling and membrane biosynthesis. Additionally, multiple diseases, such as obesity, fatty liver, cardiovascular diseases and cancer, are related to the metabolic disorders of LDs. In various cancer cells, LD accumulation is associated with resistance to cell death, reduced effectiveness of chemotherapeutic drugs, and increased proliferation and aggressiveness. In this work, we present a new viscosity-sensitive, green-emitting BODIPY probe capable of distinguishing between ordered and disordered lipid phases and selectively internalising into LDs of live cells. Through the use of fluorescence lifetime imaging microscopy (FLIM), we demonstrate that LDs in live cancer (A549) and non-cancer (HEK 293T) cells have vastly different microviscosities. Additionally, we quantify the microviscosity changes in LDs under the influence of DNA-damaging chemotherapy drugs doxorubicin and etoposide. Finally, we show that doxorubicin and etoposide have different effects on the microviscosities of LDs in chemotherapy-resistant A549 cancer cells.


Assuntos
Compostos de Boro , Gotículas Lipídicas , Neoplasias , Gotículas Lipídicas/metabolismo , Corantes Fluorescentes/farmacologia , Corantes Fluorescentes/metabolismo , Etoposídeo/metabolismo , Lipídeos , Doxorrubicina/farmacologia , Doxorrubicina/metabolismo , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo
5.
Nat Cell Biol ; 26(3): 331-345, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38454048

RESUMO

Lipid droplets are dynamic organelles that store neutral lipids, serve the metabolic needs of cells, and sequester lipids to prevent lipotoxicity and membrane damage. Here we review the current understanding of the mechanisms of lipid droplet biogenesis and turnover, the transfer of lipids and metabolites at membrane contact sites, and the role of lipid droplets in regulating fatty acid flux in lipotoxicity and cell death.


Assuntos
Gotículas Lipídicas , Metabolismo dos Lipídeos , Gotículas Lipídicas/metabolismo , Homeostase , Ácidos Graxos/metabolismo
6.
J Virol ; 98(4): e0017124, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38488361

RESUMO

The global impact of emerging viral infections emphasizes the urgent need for effective broad-spectrum antivirals. The cellular organelle, lipid droplet (LD), is utilized by many types of viruses for replication, but its reduction does not affect cell survival. Therefore, LD is a potential target for developing broad-spectrum antivirals. In this study, we found that 2-bromopalmitate (2 BP), a previously defined palmitoylation inhibitor, depletes LD across all studied cell lines and exerts remarkable antiviral effects on different coronaviruses. We comprehensively utilized 2 BP, alongside other palmitoylation inhibitors such as cerulenin and 2-fluoro palmitic acid (2-FPA), as well as the enhancer palmostatin B and evaluated their impact on LD and the replication of human coronaviruses (hCoV-229E, hCoV-Oc43) and murine hepatitis virus (MHV-A59) at non-cytotoxic concentrations. While cerulenin and 2-FPA exhibited moderate inhibition of viral replication, 2 BP exhibited a much stronger suppressive effect on MHV-A59 replication, although they share similar inhibitory effects on palmitoylation. As expected, palmostatin B significantly enhanced viral replication, it failed to rescue the inhibitory effects of 2 BP, whereas it effectively counteracted the effects of cerulenin and 2-FPA. This suggests that the mechanism that 2 BP used to inhibit viral replication is beyond palmitoylation inhibition. Further investigations unveil that 2 BP uniquely depletes LDs, a phenomenon not exhibited by 2-FPA and cerulenin. Importantly, the depletion of LDs was closely associated with the inhibition of viral replication because the addition of oleic acid to 2 BP significantly rescued LD depletion and its inhibitory effects on MHV-A59. Our findings indicate that the inhibitory effects of 2 BP on viral replication primarily stem from LD disruption rather than palmitoylation inhibition. Intriguingly, fatty acid (FA) assays demonstrated that 2 BP reduces the FA level in mitochondria while concurrently increasing FA levels in the cytoplasm. These results highlight the crucial role of LDs in viral replication and uncover a novel biological activity of 2 BP. These insights contribute to the development of broad-spectrum antiviral strategies. IMPORTANCE: In our study, we conducted a comparative investigation into the antiviral effects of palmitoylation inhibitors including 2-bromopalmitate (2-BP), 2-fluoro palmitic acid (2-FPA), and cerulenin. Surprisingly, we discovered that 2-BP has superior inhibitory effects on viral replication compared to 2-FPA and cerulenin. However, their inhibitory effects on palmitoylation were the same. Intrigued by this finding, we delved deeper into the underlying mechanism of 2-BP's potent antiviral activity, and we unveiled a novel biological activity of 2-BP: depletion of lipid droplets (LDs). Importantly, we also highlighted the crucial role of LDs in viral replication. Our insights shed new light on the antiviral mechanism of LD depletion paving the way for the development of broad-spectrum antiviral strategies by targeting LDs.


Assuntos
Coronavirus , Gotículas Lipídicas , Palmitatos , Propiolactona/análogos & derivados , Camundongos , Animais , Humanos , Gotículas Lipídicas/metabolismo , Ácido Palmítico/farmacologia , Ácido Palmítico/metabolismo , Cerulenina/metabolismo , Cerulenina/farmacologia , Replicação Viral , Antivirais/farmacologia , Antivirais/metabolismo
7.
Int J Mol Sci ; 25(6)2024 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-38542220

RESUMO

The accumulation of lipid droplets (LDs) and ceramides (Cer) is linked to non-alcoholic fatty liver disease (NAFLD), regularly co-existing with type 2 diabetes and decreased immune function. Chronic inflammation and increased disease severity in viral infections are the hallmarks of the obesity-related immunopathology. The upregulation of neutral sphingomyelinase-2 (NSM2) has shown to be associated with the pathology of obesity in tissues. Nevertheless, the role of sphingolipids and specifically of NSM2 in the regulation of immune cell response to a fatty acid (FA) rich environment is poorly studied. Here, we identified the presence of the LD marker protein perilipin 3 (PLIN3) in the intracellular nano-environment of NSM2 using the ascorbate peroxidase APEX2-catalyzed proximity-dependent biotin labeling method. In line with this, super-resolution structured illumination microscopy (SIM) shows NSM2 and PLIN3 co-localization in LD organelles in the presence of increased extracellular concentrations of oleic acid (OA). Furthermore, the association of enzymatically active NSM2 with isolated LDs correlates with increased Cer levels in these lipid storage organelles. NSM2 enzymatic activity is not required for NSM2 association with LDs, but negatively affects the LD numbers and cellular accumulation of long-chain unsaturated triacylglycerol (TAG) species. Concurrently, NSM2 expression promotes mitochondrial respiration and fatty acid oxidation (FAO) in response to increased OA levels, thereby shifting cells to a high energetic state. Importantly, endogenous NSM2 activity is crucial for primary human CD4+ T cell survival and proliferation in a FA rich environment. To conclude, our study shows a novel NSM2 intracellular localization to LDs and the role of enzymatically active NSM2 in metabolic response to enhanced FA concentrations in T cells.


Assuntos
Diabetes Mellitus Tipo 2 , Esfingomielina Fosfodiesterase , Humanos , Diabetes Mellitus Tipo 2/metabolismo , Ácidos Graxos/metabolismo , Gotículas Lipídicas/metabolismo , Metabolismo dos Lipídeos , Obesidade/metabolismo , Ácido Oleico/metabolismo , Esfingomielina Fosfodiesterase/metabolismo , Linfócitos T/metabolismo , Triglicerídeos/metabolismo
8.
J Cell Biol ; 223(6)2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38551495

RESUMO

Lipid droplets (LDs) are composed of a core of neutral lipids wrapped by a phospholipid (PL) monolayer containing several hundred proteins that vary between different cells or organisms. How LD proteins target to LDs is still largely unknown. Here, we show that RNAi knockdown or gene mutation of let-767, encoding a member of hydroxysteroid dehydrogenase (HSD), displaced the LD localization of three well-known LD proteins: DHS-3 (dehydrogenase/reductase), PLIN-1 (perilipin), and DGAT-2 (diacylglycerol O-acyltransferase 2), and also prevented LD growth in Caenorhabditis elegans. LET-767 interacts with ARF-1 (ADP-ribosylation factor 1) to prevent ARF-1 LD translocation for appropriate LD protein targeting and lipid homeostasis. Deficiency of LET-767 leads to the release of ARF-1, which further recruits and promotes translocation of ATGL-1 (adipose triglyceride lipase) to LDs for lipolysis. The displacement of LD proteins caused by LET-767 deficiency could be reversed by inhibition of either ARF-1 or ATGL-1. Our work uncovers a unique LET-767 for determining LD protein targeting and maintaining lipid homeostasis.


Assuntos
Oxirredutases do Álcool , Proteínas de Caenorhabditis elegans , Gotículas Lipídicas , Homeostase , Lipase/genética , Proteínas Associadas a Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/metabolismo , Metabolismo dos Lipídeos/genética , Lipídeos , Lipólise/fisiologia , Proteínas/metabolismo , Caenorhabditis elegans , Animais , Oxirredutases do Álcool/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo
9.
Lipids Health Dis ; 23(1): 91, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38539242

RESUMO

BACKGROUND: ß-Propeller protein-associated neurodegeneration (BPAN) is a genetic neurodegenerative disease caused by mutations in WDR45. The impairment of autophagy caused by WDR45 deficiency contributes to the pathogenesis of BPAN; however, the pathomechanism of this disease is largely unknown. Lipid dyshomeostasis is involved in neurogenerative diseases, but whether lipid metabolism is affected by Wdr45 deficiency and whether lipid dyshomeostasis contributes to the progression of BPAN are unclear. METHODS: We generated Wdr45 knockout SN4741 cell lines using CRISPR‒Cas9-mediated genome editing, then lipid droplets (LDs) were stained using BODIPY 493/503. Chaperone-mediated autophagy was determined by RT-qPCR and western blotting. The expression of fatty acid synthase (Fasn) was detected by western blot in the presence or absence of the lysosomal inhibitor NH4Cl and the CMA activator AR7. The interaction between Fasn and HSC70 was analyzed using coimmunoprecipitation (Co-IP) assay. Cell viability was measured by a CCK-8 kit after treatment with the Fasn inhibitor C75 or the CMA activator AR7. RESULTS: Deletion of Wdr45 impaired chaperone-mediated autophagy (CMA), thus leading to lipid droplet (LD) accumulation. Moreover, Fasn can be degraded via CMA, and that defective CMA leads to elevated Fasn, which promotes LD formation. LD accumulation is toxic to cells; however, cell viability was not rescued by Fasn inhibition or CMA activation. Inhibition of Fasn with a low concentration of C75 did not affect cell viability but decreases LD density. CONCLUSIONS: These results suggested that Fasn is essential for cell survival but that excessive Fasn leads to LD accumulation in Wdr45 knockout cells.


Assuntos
Autofagia Mediada por Chaperonas , Doenças Neurodegenerativas , Humanos , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Gotículas Lipídicas/metabolismo , Doenças Neurodegenerativas/genética , Doenças Neurodegenerativas/metabolismo , Autofagia/genética , Ácido Graxo Sintases/metabolismo , Lipídeos
10.
Int J Mol Sci ; 25(6)2024 Mar 09.
Artigo em Inglês | MEDLINE | ID: mdl-38542126

RESUMO

Lipophagy is a cellular pathway targeting the lysosomal degradation of lipid droplets, playing a role in promoting lipid turnover and renewal. Abnormal lipophagy processes can lead to the occurrence and development of non-alcoholic fatty liver disease (NAFLD), characterized by the deposition of lipid droplets (LDs) in the liver. The importance of exercise training in preventing and improving NAFLD has been well-established, but the exact mechanisms remain unclear. Recent research findings suggest that lipophagy may serve as a crucial hub for liver lipid turnover under exercise conditions. Exercise may alleviate hepatic lipid accumulation and mitigate inflammatory responses and fibrosis through lipophagy, thereby improving the onset and progression of NAFLD.


Assuntos
Hepatopatia Gordurosa não Alcoólica , Humanos , Hepatopatia Gordurosa não Alcoólica/terapia , Hepatopatia Gordurosa não Alcoólica/metabolismo , Metabolismo dos Lipídeos/fisiologia , Fígado/metabolismo , Autofagia/fisiologia , Gotículas Lipídicas/metabolismo , Terapia por Exercício , Lipídeos
11.
Cancer Immunol Immunother ; 73(5): 78, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38554152

RESUMO

BACKGROUND: Lipid droplets (LDs) as major lipid storage organelles are recently reported to be innate immune hubs. Perilipin-3 (PLIN3) is indispensable for the formation and accumulation of LDs. Since cancer patients show dysregulated lipid metabolism, we aimed to elaborate the role of LDs-related PLIN3 in oral squamous cell carcinoma (OSCC). METHODS: PLIN3 expression patterns (n = 87), its immune-related landscape (n = 74) and association with B7-H2 (n = 51) were assessed by immunohistochemistry and flow cytometry. Real-time PCR, Western blot, Oil Red O assay, immunofluorescence, migration assay, spheroid-forming assay and flow cytometry were performed for function analysis. RESULTS: Spotted LDs-like PLIN3 staining was dominantly enriched in tumor cells than other cell types. PLIN3high tumor showed high proliferation index with metastasis potential, accompanied with less CD3+CD8+ T cells in peripheral blood and in situ tissue, conferring immunosuppressive microenvironment and shorter postoperative survival. Consistently, PLIN3 knockdown in tumor cells not only reduced LD deposits and tumor migration, but benefited for CD8+ T cells activation in co-culture system with decreased B7-H2. An OSCC subpopulation harbored PLIN3highB7-H2high tumor showed more T cells exhaustion, rendering higher risk of cancer-related death (95% CI 1.285-6.851). CONCLUSIONS: LDs marker PLIN3 may be a novel immunotherapeutic target in OSCC.


Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Bucais , Humanos , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Linfócitos T CD8-Positivos/metabolismo , Neoplasias de Cabeça e Pescoço/metabolismo , Gotículas Lipídicas/metabolismo , Neoplasias Bucais/genética , Neoplasias Bucais/metabolismo , Oncogenes , Perilipina-3/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço/metabolismo , Microambiente Tumoral
12.
Nature ; 628(8006): 154-161, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38480892

RESUMO

Several genetic risk factors for Alzheimer's disease implicate genes involved in lipid metabolism and many of these lipid genes are highly expressed in glial cells1. However, the relationship between lipid metabolism in glia and Alzheimer's disease pathology remains poorly understood. Through single-nucleus RNA sequencing of brain tissue in Alzheimer's disease, we have identified a microglial state defined by the expression of the lipid droplet-associated enzyme ACSL1 with ACSL1-positive microglia being most abundant in patients with Alzheimer's disease having the APOE4/4 genotype. In human induced pluripotent stem cell-derived microglia, fibrillar Aß induces ACSL1 expression, triglyceride synthesis and lipid droplet accumulation in an APOE-dependent manner. Additionally, conditioned media from lipid droplet-containing microglia lead to Tau phosphorylation and neurotoxicity in an APOE-dependent manner. Our findings suggest a link between genetic risk factors for Alzheimer's disease with microglial lipid droplet accumulation and neurotoxic microglia-derived factors, potentially providing therapeutic strategies for Alzheimer's disease.


Assuntos
Doença de Alzheimer , Apolipoproteína E4 , Gotículas Lipídicas , Microglia , Animais , Feminino , Humanos , Masculino , Camundongos , Doença de Alzheimer/genética , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Apolipoproteína E4/genética , Apolipoproteína E4/metabolismo , Células-Tronco Pluripotentes Induzidas/citologia , Gotículas Lipídicas/metabolismo , Gotículas Lipídicas/patologia , Microglia/citologia , Microglia/metabolismo , Microglia/patologia , Triglicerídeos , Proteínas tau , Meios de Cultivo Condicionados , Fosforilação , Predisposição Genética para Doença
13.
J Physiol ; 602(5): 891-912, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38429930

RESUMO

Skeletal muscle cellular development requires the integrated assembly of mitochondria and other organelles adjacent to the sarcomere in support of muscle contractile performance. However, it remains unclear how interactions among organelles and with the sarcomere relates to the development of muscle cell function. Here, we combine 3D volume electron microscopy, proteomic analyses, and live cell functional imaging to investigate the postnatal reorganization of mitochondria-organelle interactions in skeletal muscle. We show that while mitochondrial networks are disorganized and loosely associated with the contractile apparatus at birth, contact sites among mitochondria, lipid droplets and the sarcoplasmic reticulum are highly abundant in neonatal muscles. The maturation process is characterized by a transition to highly organized mitochondrial networks wrapped tightly around the muscle sarcomere but also to less frequent interactions with both lipid droplets and the sarcoplasmic reticulum. Concomitantly, expression of proteins involved in mitochondria-organelle membrane contact sites decreases during postnatal development in tandem with a decrease in abundance of proteins associated with sarcomere assembly despite an overall increase in contractile protein abundance. Functionally, parallel measures of mitochondrial membrane potential, NADH redox status, and NADH flux within intact cells revealed that mitochondria in adult skeletal muscle fibres maintain a more activated electron transport chain compared with neonatal muscle mitochondria. These data demonstrate a developmental redesign reflecting a shift from muscle cell assembly and frequent inter-organelle communication toward a muscle fibre with mitochondrial structure, interactions, composition and function specialized to support contractile function. KEY POINTS: Mitochondrial network organization is remodelled during skeletal muscle postnatal development. The mitochondrial outer membrane is in frequent contact with other organelles at birth and transitions to more close associations with the contractile apparatus in mature muscles. Mitochondrial energy metabolism becomes more activated during postnatal development. Understanding the developmental redesign process within skeletal muscle cells may help pinpoint specific areas of deficit in muscles with developmental disorders.


Assuntos
NAD , Proteômica , Humanos , Adulto , Recém-Nascido , NAD/metabolismo , Mitocôndrias/metabolismo , Músculo Esquelético/metabolismo , Mitocôndrias Musculares/metabolismo , Gotículas Lipídicas/metabolismo
14.
J Cell Biol ; 223(4)2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38466168

RESUMO

The secreted ApoE protein is a major regulator of lipid transport between brain cells. In this issue, Windham et al. (https://doi.org/10.1083/jcb.202305003) uncover a novel intracellular role for ApoE at the lipid droplet surface, where it regulates lipid droplet size and composition.


Assuntos
Apolipoproteínas E , Gotículas Lipídicas , Apolipoproteínas E/metabolismo , Transporte Biológico , Gotículas Lipídicas/metabolismo , Humanos , Animais
15.
Genomics ; 116(2): 110817, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38431031

RESUMO

Perilipin-2 (PLIN2) can anchor to lipid droplets (LDs) and play a crucial role in regulating nascent LDs formation. Bimolecular fluorescence complementation (BiFC) and flow cytometry were examined to verify the PLIN2-CGI-58 interaction efficiency in bovine adipocytes. GST-Pulldown assay was used to detect the key site arginine315 function in PLIN2-CGI-58 interaction. Experiments were also examined to research these mutations function of PLIN2 in LDs formation during adipocytes differentiation, LDs were measured after staining by BODIPY, lipogenesis-related genes were also detected. Results showed that Leucine (L371A, L311A) and glycine (G369A, G376A) mutations reduced interaction efficiencies. Serine (S367A) mutations enhanced the interaction efficiency. Arginine (R315A) mutations resulted in loss of fluorescence in the cytoplasm and disrupted the interaction with CGI-58, as verified by pulldown assay. R315W mutations resulted in a significant increase in the number of LDs compared with wild-type (WT) PLIN2 or the R315A mutations. Lipogenesis-related genes were either up- or downregulated when mutated PLIN2 interacted with CGI-58. Arginine315 in PLIN2 is required for the PLIN2-CGI-58 interface and could regulate nascent LD formation and lipogenesis. This study is the first to study amino acids on the PLIN2 interface during interaction with CGI-58 in bovine and highlight the role played by PLIN2 in the regulation of bovine adipocyte lipogenesis.


Assuntos
Arginina , Gotículas Lipídicas , Animais , Bovinos , Perilipina-2/genética , Perilipina-2/química , Perilipina-2/metabolismo , Arginina/genética , Arginina/metabolismo , Gotículas Lipídicas/metabolismo , Mutação , Adipócitos/metabolismo , Metabolismo dos Lipídeos
16.
J Agric Food Chem ; 72(11): 6040-6052, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38454851

RESUMO

One type of large and intricate post-translational modification of milk proteins that has significant biological implications is phosphorylation. The characterization of phosphoproteins found in the bovine milk fat globule membrane (MFGM) is still mostly unknown. Here, label-free phosphoproteomics was used to identify 94 phosphorylation sites from 54 MFGM phosphoproteins in bovine colostrum (BC) and 136 phosphorylation sites from 91 MFGM phosphoproteins in bovine mature milk (BM). αs1-Casein and ß-casein were the most phosphorylated proteins in bovine colostrum. In bovine mature milk, perilipin-2 was the protein with the greatest number of phosphorylation sites. The results show that bovine colostrum MFGM phosphoproteins were mainly involved in immune function, whereas bovine mature MFGM phosphoproteins were mainly involved in metabolic function. Plasminogen and osteopontin were the most strongly interacting proteins in colostrum, whereas perilipin-2 was the most strongly interacting protein in bovine mature milk. This work demonstrates the unique alterations in the phosphorylation manner of the bovine MFGM protein during lactation and further expands our knowledge of the site characteristics of bovine MFGM phosphoproteins. This result confirms the value of MFGM as a reference ingredient for infant formula during different stages.


Assuntos
Colostro , Glicoproteínas , Leite , Feminino , Gravidez , Lactente , Humanos , Animais , Colostro/metabolismo , Perilipina-2/metabolismo , Leite/metabolismo , Glicolipídeos/metabolismo , Gotículas Lipídicas/metabolismo , Proteínas do Leite/metabolismo , Caseínas/metabolismo
17.
Anal Chem ; 96(11): 4709-4715, 2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38457637

RESUMO

The varied functions of lipid droplets, which encompass the regulation of lipid and energy homeostasis, as well as their association with the occurrence of various metabolic diseases, are intricately linked to their dynamic properties. Super-resolution imaging techniques have emerged to decipher physiological processes and molecular mechanisms on the nanoscale. However, achieving long-term dynamic super-resolution imaging faces challenges due to the need for fluorescent probes with high photostability. This paper introduces LD-CF, a "buffering probe" for imaging lipid droplet dynamics using structured illumination microscopy (SIM). The polarity-sensitive LD-CF eliminates background fluorescence with a "cyan filter" strategy, enabling wash-free imaging of lipid droplets. In the fluorescent "off" state outside droplets, the probes act as a "buffering pool", replacing photobleached probes inside droplets and enabling photostable long-term SIM imaging. With this probe, three modes of lipid droplet fusion were observed, including the discovery of fusion from large to small lipid droplets. Fluorescence intensity tracking also revealed the direction of lipid transport during the lipid droplet fusion.


Assuntos
Corantes Fluorescentes , Gotículas Lipídicas , Corantes Fluorescentes/metabolismo , Gotículas Lipídicas/metabolismo , Microscopia de Fluorescência/métodos , Transporte Biológico , Lipídeos
18.
Curr Opin Cell Biol ; 87: 102342, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38428224

RESUMO

Lipid droplets (LDs), once considered mere storage depots for lipids, have gained recognition for their intricate roles in cellular processes, including metabolism, membrane trafficking, and disease states like obesity and cancer. This review explores label-free imaging techniques' applications in LD research. We discuss holotomography and vibrational spectroscopic microscopy, emphasizing their potential for studying LDs without molecular labels, and we highlight the growing integration of artificial intelligence. Clinical applications in disease diagnosis and therapy are also considered.


Assuntos
Inteligência Artificial , Gotículas Lipídicas , Gotículas Lipídicas/metabolismo , Microscopia , Metabolismo dos Lipídeos
19.
Anal Chem ; 96(14): 5615-5624, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38544396

RESUMO

Abnormal lipid droplets (LDs) are known to be intimately bound with the occurrence and development of cancer, allowing LDs to be critical biomarkers for cancers. Aggregation-induced emission luminogens (AIEgens), with efficient reactive oxygen species (ROS) production performance, are prime photosensitizers (PSs) for photodynamic therapy (PDT) with imaging. Therefore, the development of dual-functional fluorescent probes with aggregation-induced emission (AIE) characteristics that enable both simultaneous LD monitoring and imaging-guided PDT is essential for concurrent cancer diagnosis and treatment. Herein, we reported the development of a novel LD-targeting fluorescent probe (TDTI) with AIE performance, which was expected to realize the integration of cancer diagnosis through LD visualization and cancer treatment via PDT. We demonstrated that TDTI, with typical AIE characteristics and excellent photostability, could target LDs with high specificity, which enables the dynamic tracking of LDs in living cells, specific imaging of LDs in zebrafish, and the differentiation of cancer cells from normal cells for cancer diagnosis. Meanwhile, TDTI exhibited fast ROS generation ability (achieving equilibrium within 60 s) under white light irradiation (10 mW/cm2). The cell apoptosis assay revealed that TDTI effectively induced growth inhibition and apoptosis of HeLa cells. Further, the results of PDT in vivo indicated that TDTI had a good antitumor effect on the tumor-bearing mice model. Collectively, these results highlight the potential utility of the dual-functional fluorescent probe TDTI in the integrated diagnosis and treatment of cancer.


Assuntos
Neoplasias , Fotoquimioterapia , Humanos , Animais , Camundongos , Células HeLa , Corantes Fluorescentes , Gotículas Lipídicas/metabolismo , Fotoquimioterapia/métodos , Espécies Reativas de Oxigênio/metabolismo , Peixe-Zebra/metabolismo , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Neoplasias/diagnóstico por imagem , Neoplasias/tratamento farmacológico
20.
Curr Opin Clin Nutr Metab Care ; 27(2): 91-97, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38320158

RESUMO

PURPOSE OF REVIEW: This review aims to discuss the most recent evidence exploring the role of lipid droplets in steatotic liver disease (SLD). We highlight the breadth of mechanisms by which lipid droplets may contribute to the progression of SLD with a particular focus on the role of lipid droplets as inducers of mechanical stress within hepatocytes and genetic mutations in lipid droplet associated proteins. Finally, this review provides an update on clinical trials exploring the therapeutic potential and strategies targeting lipid droplets. RECENT FINDINGS: The size, composition and location of hepatic lipid droplets strongly influence the pathological role of these organelles in SLD. Emerging studies are beginning to elucidate the importance of lipid droplet induced hepatocyte mechanical stress. Novel strategies targeting lipid droplets, including the effects of lipid droplet associated protein mutations, show promising therapeutic potential. SUMMARY: Much more than a histological feature, lipid droplets are complex heterogenous organelles crucial to cellular metabolism with important causative roles in the development and progression of SLD. Lipid droplet induced mechanical stress may exacerbate hepatic inflammation and fibrogenesis and potentially contribute to the development of a pro-carcinogenic hepatic environment. The integration of advancements in genetics and molecular biology in upcoming treatments aspires to transcend symptomatic alleviation and address the fundamental causes and pathological development of SLD.


Assuntos
Fígado Gorduroso , Gotículas Lipídicas , Humanos , Gotículas Lipídicas/metabolismo , Metabolismo dos Lipídeos , Fígado Gorduroso/metabolismo , Fígado/metabolismo , Proteínas/metabolismo
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