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2.
Gene Ther ; 31(9-10): 445-454, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-39069561

RESUMO

Lipodystrophy is a rare disorder which can be life-threatening. Here individuals fail to develop or maintain appropriate adipose tissue stores. This typically causes severe metabolic complications, including hepatic steatosis and lipoatrophic diabetes. There is no cure for lipodystrophy, and treatment options remain very limited. Here we evaluate whether tissue-selective adeno-associated virus (AAV) vectors can provide a targeted form of gene therapy for lipodystrophy, using a preclinical lipodystrophic mouse model of Bscl2 deficiency. We designed AAV vectors containing the mini/aP2 or thyroxine-binding globulin promoter to selectively target adipose or liver respectively. The AAV-aP2 vectors also contained the liver-specific microRNA-122 target sequence, restricting hepatic transgene expression. Systemic delivery of AAV-aP2 vectors overexpressing human BSCL2 restored adipose tissue development and metabolic health in lipodystrophic mice without detectable expression in the liver. High doses (1 × 1012 GCs) of liver-selective vectors led to off target expression and adipose tissue development, whilst low doses (1 × 1010 GCs) expressed selectively and robustly in the liver but did not improve metabolic health. This reveals that adipose tissue-selective, but not liver directed, AAV-mediated gene therapy is sufficient to substantially recover metabolic health in generalised lipodystrophy. This provides an exciting potential new avenue for an effective, targeted, and thereby safer therapeutic intervention.


Assuntos
Tecido Adiposo , Dependovirus , Terapia Genética , Vetores Genéticos , Lipodistrofia Generalizada Congênita , Fígado , Animais , Terapia Genética/métodos , Camundongos , Dependovirus/genética , Vetores Genéticos/genética , Vetores Genéticos/administração & dosagem , Fígado/metabolismo , Humanos , Lipodistrofia Generalizada Congênita/terapia , Lipodistrofia Generalizada Congênita/genética , Lipodistrofia Generalizada Congênita/metabolismo , Tecido Adiposo/metabolismo , Modelos Animais de Doenças , Subunidades gama da Proteína de Ligação ao GTP/genética , Subunidades gama da Proteína de Ligação ao GTP/metabolismo
3.
Nature ; 539(7629): 390-395, 2016 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-27799657

RESUMO

Intermediary metabolism generates substrates for chromatin modification, enabling the potential coupling of metabolic and epigenetic states. Here we identify a network linking metabolic and epigenetic alterations that is central to oncogenic transformation downstream of the liver kinase B1 (LKB1, also known as STK11) tumour suppressor, an integrator of nutrient availability, metabolism and growth. By developing genetically engineered mouse models and primary pancreatic epithelial cells, and employing transcriptional, proteomics, and metabolic analyses, we find that oncogenic cooperation between LKB1 loss and KRAS activation is fuelled by pronounced mTOR-dependent induction of the serine-glycine-one-carbon pathway coupled to S-adenosylmethionine generation. At the same time, DNA methyltransferases are upregulated, leading to elevation in DNA methylation with particular enrichment at retrotransposon elements associated with their transcriptional silencing. Correspondingly, LKB1 deficiency sensitizes cells and tumours to inhibition of serine biosynthesis and DNA methylation. Thus, we define a hypermetabolic state that incites changes in the epigenetic landscape to support tumorigenic growth of LKB1-mutant cells, while resulting in potential therapeutic vulnerabilities.


Assuntos
Transformação Celular Neoplásica , Metilação de DNA , Proteínas Serina-Treonina Quinases/deficiência , Proteínas Serina-Treonina Quinases/metabolismo , Serina/metabolismo , Quinases Proteína-Quinases Ativadas por AMP , Proteínas Quinases Ativadas por AMP , Animais , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Cromatina/genética , Cromatina/metabolismo , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA/efeitos dos fármacos , Inibidores Enzimáticos/farmacologia , Células Epiteliais/metabolismo , Inativação Gênica , Genes Supressores de Tumor , Glicina/metabolismo , Glicólise , Humanos , Camundongos , Ductos Pancreáticos/citologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Retroelementos/genética , S-Adenosilmetionina/metabolismo , Serina/biossíntese , Serina-Treonina Quinases TOR/metabolismo , Transaminases/metabolismo
4.
BMC Cell Biol ; 19(1): 11, 2018 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-29973136

RESUMO

BACKGROUND: Apoptosis, the most well-known type of programmed cell death, can induce in a paracrine manner a proliferative response in neighboring surviving cells called apoptosis-induced proliferation (AiP). While having obvious benefits when triggered in developmental processes, AiP is a serious obstacle in cancer therapy, where apoptosis is frequently induced by chemotherapy. Therefore, in this study, we evaluated the capacity of an alternative type of cell death, called caspase-independent cell death, to promote proliferation. RESULTS: Using a novel in vitro isogenic cellular model to trigger either apoptosis or caspase-independent cell death, we found that the later has no obvious compensatory proliferation effects on neighboring cells. CONCLUSIONS: This study enforces the idea that alternative types of cell death such as caspase-independent cell death could be considered to replace apoptosis in the context of cancer treatment.


Assuntos
Apoptose , Caspases/metabolismo , Melanoma/enzimologia , Melanoma/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Humanos , Modelos Biológicos
5.
Front Endocrinol (Lausanne) ; 15: 1379228, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38745956

RESUMO

Aims: Individuals with lipodystrophies typically suffer from metabolic disease linked to adipose tissue dysfunction including lipoatrophic diabetes. In the most severe forms of lipodystrophy, congenital generalised lipodystrophy, adipose tissue may be almost entirely absent. Better therapies for affected individuals are urgently needed. Here we performed the first detailed investigation of the effects of a glucagon like peptide-1 receptor (GLP-1R) agonist in lipoatrophic diabetes, using mice with generalised lipodystrophy. Methods: Lipodystrophic insulin resistant and glucose intolerant seipin knockout mice were treated with the GLP-1R agonist liraglutide either acutely preceding analyses of insulin and glucose tolerance or chronically prior to metabolic phenotyping and ex vivo studies. Results: Acute liraglutide treatment significantly improved insulin, glucose and pyruvate tolerance. Once daily injection of seipin knockout mice with liraglutide for 14 days led to significant improvements in hepatomegaly associated with steatosis and reduced markers of liver fibrosis. Moreover, liraglutide enhanced insulin secretion in response to glucose challenge with concomitantly improved glucose control. Conclusions: GLP-1R agonist liraglutide significantly improved lipoatrophic diabetes and hepatic steatosis in mice with generalised lipodystrophy. This provides important insights regarding the benefits of GLP-1R agonists for treating lipodystrophy, informing more widespread use to improve the health of individuals with this condition.


Assuntos
Receptor do Peptídeo Semelhante ao Glucagon 1 , Lipodistrofia , Liraglutida , Animais , Masculino , Camundongos , Glicemia/metabolismo , Modelos Animais de Doenças , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Hipoglicemiantes/farmacologia , Hipoglicemiantes/uso terapêutico , Insulina/metabolismo , Resistência à Insulina , Lipodistrofia/tratamento farmacológico , Lipodistrofia/metabolismo , Liraglutida/farmacologia , Liraglutida/uso terapêutico , Doenças Metabólicas/tratamento farmacológico , Doenças Metabólicas/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout
6.
Mol Ther Methods Clin Dev ; 27: 206-216, 2022 Dec 08.
Artigo em Inglês | MEDLINE | ID: mdl-36320417

RESUMO

Congenital generalized lipodystrophy type 2 is a serious multisystem disorder with limited treatment options. It is caused by mutations affecting the BSCL2 gene, which encodes the protein seipin. Patients with congenital generalized lipodystrophy type 2 lack both metabolic and mechanical adipose tissue and develop severe metabolic complications including hepatic steatosis, lipoatrophic diabetes, and cardiovascular disease. Gene therapies are becoming viable treatments, helping to alleviate inherited and acquired human disorders. We aimed to determine whether gene therapy could offer an effective form of medical intervention for lipodystrophy. We examined whether systemic adeno-associated virus delivery of human BSCL2 could reverse metabolic disease in seipin knockout mice, where white adipose tissue is absent. We reveal that adeno-associated virus gene therapy targets adipose progenitor cells in vivo and substantially restores white adipose tissue development in adult seipin knockout mice. This resulted in both rapid and prolonged beneficial effects to metabolic health in this pre-clinical mouse model of congenital generalized lipodystrophy type 2. Hyperglycemia was normalized within 2 weeks post-treatment together with normalization of severe insulin resistance. We propose that gene therapy offers great potential as a therapeutic strategy to correct multiple metabolic complications in patients with congenital lipodystrophy.

7.
J Clin Med ; 10(3)2021 Jan 23.
Artigo em Inglês | MEDLINE | ID: mdl-33498782

RESUMO

Congenital Generalized Lipodystrophy type 2 (CGL2) is the most severe form of lipodystrophy and is caused by mutations in the BSCL2 gene. Affected patients exhibit a near complete lack of adipose tissue and suffer severe metabolic disease. A recent study identified infection as a major cause of death in CGL2 patients, leading us to examine whether Bscl2 loss could directly affect the innate immune response. We generated a novel mouse model selectively lacking Bscl2 in the myeloid lineage (LysM-B2KO) and also examined the function of bone-marrow-derived macrophages (BMDM) isolated from global Bscl2 knockout (SKO) mice. LysM-B2KO mice failed to develop lipodystrophy and metabolic disease, providing a model to study the direct role of Bscl2 in myeloid lineage cells. Lipopolysaccharide-mediated stimulation of inflammatory cytokines was not impaired in LysM-B2KO mice or in BMDM isolated from either LysM-B2KO or SKO mice. Additionally, intracellular fate and clearance of bacteria in SKO BMDM challenged with Staphylococcus aureus was indistinguishable from that in BMDM isolated from littermate controls. Overall, our findings reveal that selective Bscl2 deficiency in macrophages does not critically impact the innate immune response to infection. Instead, an increased susceptibility to infection in CGL2 patients is likely to result from severe metabolic disease.

8.
Sci Rep ; 10(1): 3259, 2020 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-32094408

RESUMO

Seipin deficiency causes severe congenital generalized lipodystrophy (CGL) and metabolic disease. However, how seipin regulates adipocyte development and function remains incompletely understood. We previously showed that seipin acts as a scaffold protein for AGPAT2, whose disruption also causes CGL. More recently, seipin has been reported to promote adipogenesis by directly inhibiting GPAT3, leading to the suggestion that GPAT inhibitors could offer novel treatments for CGL. Here we investigated the interactions between seipin, GPAT3 and AGPAT2. We reveal that seipin and GPAT3 associate via direct interaction and that seipin can simultaneously bind GPAT3 and AGPAT2. Inhibiting the expression of seipin, AGPAT2 or GPAT3 led to impaired induction of early markers of adipocyte differentiation in cultured cells. However, consistent with normal adipose mass in GPAT3-null mice, GPAT3 inhibition did not prevent the formation of mature adipocytes. Nonetheless, loss of GPAT3 in seipin-deficient preadipocytes exacerbated the failure of adipogenesis in these cells. Thus, our data indicate that GPAT3 plays a modest positive role in adipogenesis and argue against the potential of GPAT inhibitors to rescue white adipose tissue mass in CGL2. Overall, our study reveals novel mechanistic insights regarding the molecular pathogenesis of severe lipodystrophy caused by mutations in either seipin or AGPAT2.


Assuntos
1-Acilglicerol-3-Fosfato O-Aciltransferase/metabolismo , Aciltransferases/metabolismo , Adipócitos/citologia , Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Células 3T3-L1 , Adipogenia , Tecido Adiposo/patologia , Animais , Diferenciação Celular , Diabetes Mellitus Tipo 2/metabolismo , Regulação da Expressão Gênica , Células HEK293 , Humanos , Metabolismo dos Lipídeos , Camundongos , Camundongos Endogâmicos C3H , Microscopia de Força Atômica , Mutação
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