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1.
Mol Cell ; 83(16): 2991-3009.e13, 2023 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-37567175

RESUMO

The PIP3/PI3K network is a central regulator of metabolism and is frequently activated in cancer, commonly by loss of the PIP3/PI(3,4)P2 phosphatase, PTEN. Despite huge research investment, the drivers of the PI3K network in normal tissues and how they adapt to overactivation are unclear. We find that in healthy mouse prostate PI3K activity is driven by RTK/IRS signaling and constrained by pathway feedback. In the absence of PTEN, the network is dramatically remodeled. A poorly understood YXXM- and PIP3/PI(3,4)P2-binding PH domain-containing adaptor, PLEKHS1, became the dominant activator and was required to sustain PIP3, AKT phosphorylation, and growth in PTEN-null prostate. This was because PLEKHS1 evaded pathway-feedback and experienced enhanced PI3K- and Src-family kinase-dependent phosphorylation of Y258XXM, eliciting PI3K activation. hPLEKHS1 mRNA and activating Y419 phosphorylation of hSrc correlated with PI3K pathway activity in human prostate cancers. We propose that in PTEN-null cells receptor-independent, Src-dependent tyrosine phosphorylation of PLEKHS1 creates positive feedback that escapes homeostasis, drives PIP3 signaling, and supports tumor progression.


Assuntos
PTEN Fosfo-Hidrolase , Neoplasias da Próstata , Animais , Humanos , Masculino , Camundongos , Homeostase , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Próstata/patologia , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo
2.
Proc Natl Acad Sci U S A ; 121(13): e2319856121, 2024 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-38513098

RESUMO

The use of lipid nanoparticles (LNP) to encapsulate and deliver mRNA has become an important therapeutic advance. In addition to vaccines, LNP-mRNA can be used in many other applications. For example, targeting the LNP with anti-CD5 antibodies (CD5/tLNP) can allow for efficient delivery of mRNA payloads to T cells to express protein. As the percentage of protein expressing T cells induced by an intravenous injection of CD5/tLNP is relatively low (4-20%), our goal was to find ways to increase mRNA-induced translation efficiency. We showed that T cell activation using an anti-CD3 antibody improved protein expression after CD5/tLNP transfection in vitro but not in vivo. T cell health and activation can be increased with cytokines, therefore, using mCherry mRNA as a reporter, we found that culturing either mouse or human T cells with the cytokine IL7 significantly improved protein expression of delivered mRNA in both CD4+ and CD8+ T cells in vitro. By pre-treating mice with systemic IL7 followed by tLNP administration, we observed significantly increased mCherry protein expression by T cells in vivo. Transcriptomic analysis of mouse T cells treated with IL7 in vitro revealed enhanced genomic pathways associated with protein translation. Improved translational ability was demonstrated by showing increased levels of protein expression after electroporation with mCherry mRNA in T cells cultured in the presence of IL7, but not with IL2 or IL15. These data show that IL7 selectively increases protein translation in T cells, and this property can be used to improve expression of tLNP-delivered mRNA in vivo.


Assuntos
Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , Interleucina-7 , Lipossomos , Nanopartículas , Biossíntese de Proteínas , RNA Mensageiro , Animais , Humanos , Camundongos , Linfócitos T CD8-Positivos/efeitos dos fármacos , Linfócitos T CD8-Positivos/metabolismo , Interleucina-7/farmacologia , Biossíntese de Proteínas/efeitos dos fármacos , RNA Mensageiro/metabolismo , Camundongos Endogâmicos C57BL , Células Cultivadas , Linfócitos T CD4-Positivos/efeitos dos fármacos , Linfócitos T CD4-Positivos/imunologia
3.
EClinicalMedicine ; 76: 102844, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39391015

RESUMO

Background: Obesity drives metabolic disease development. Preventing weight gain during early adulthood could mitigate later-life chronic disease risk. Increased dietary fibre intake, leading to enhanced colonic microbial fermentation and short-chain fatty acid (SCFA) production, is associated with lower body weight. Despite national food policy recommendations to consume 30 g of dietary fibre daily, only 9% of adults achieve this target. Inulin-propionate ester (IPE) selectively increases the production of the SCFA propionate in the colon. In previous studies, IPE has prevented weight gain in middle-aged adults over 6 months, compared with the inulin control. IPE is a novel food ingredient that can be added to various commonly consumed foods with a potential health benefit. This 12-month study aimed to determine whether using IPE to increase colonic propionate prevents further weight gain in overweight younger adults. Methods: This multi-centre randomised-controlled, double-blind trial was conducted in London and Glasgow, UK. Recruited participants were individuals at risk of weight gain, aged between 20 and 40 years and had an overweight body mass index. Sealed Envelope Software was used to randomise participants to consume 10 g of IPE or inulin (control), once per day for 12 months. The primary outcome was the weight gained from baseline to 12 months, analysed by an 'Intention to Treat' strategy. The safety profile and tolerability of IPE were monitored through adverse events and compliance. This study is registered with the International Standard Randomised Controlled Trials (ISRCT) Database (ISRCT number: 16299902). Findings: Participants (n = 135 per study arm) were recruited from July 2019 to October 2021. At 12 months, there was no significant difference in baseline-adjusted mean weight gain for IPE compared with control (1.02 kg, 95% CI: -0.37 to 2.41; p = 0.15; n = 226). Neither the IPE (+1.22 kg) nor the control arm (+0.07 kg) unadjusted mean gains in body weight reached the expected 2 kg threshold. In the IPE arm, fat-free mass was greater by 1.07 kg (95% CI: 0.21-1.93), and blood glucose elevated by 0.11 mmol/L (95% CI: 0.01-0.21). Compliance, determined by intake of ≥50% sachets, was reached by 63% of IPE participants. There were no unexpected adverse events or safety concerns. Interpretation: Our study indicates that at 12 months, IPE did not differentially affect weight gain, compared with the inulin control, in adults between 20 and 40 years of age, at risk of obesity. Funding: NIHR EME Programme (15/185/16).

4.
Mol Immunol ; 142: 105-119, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34973498

RESUMO

In the late 1980s and early 1990s, the hunt for a transporter molecule ostensibly responsible for the translocation of peptides across the endoplasmic reticulum (ER) membrane yielded the successful discovery of transporter associated with antigen processing (TAP) protein. TAP is a heterodimer complex comprised of TAP1 and TAP2, which utilizes ATP to transport cytosolic peptides into the ER across its membrane. In the ER, together with other components it forms the peptide loading complex (PLC), which directs loading of high affinity peptides onto nascent major histocompatibility complex class I (MHC-I) molecules that are then transported to the cell surface for presentation to CD8+ T cells. TAP also plays a crucial role in transporting peptides into phagosomes and endosomes during cross-presentation in dendritic cells (DCs). Because of the critical role that TAP plays in both classical MHC-I presentation and cross-presentation, its expression and function are often compromised by numerous types of cancers and viruses to evade recognition by cytotoxic CD8 T cells. Here we review the discovery and function of TAP with a major focus on its role in cross-presentation in DCs. We discuss a recently described emergency route of noncanonical cross-presentation that is mobilized in DCs upon TAP blockade to restore CD8 T cell cross-priming. We also discuss the various strategies employed by cancer cells and viruses to target TAP expression or function to evade immunosurveillance - along with some strategies by which the repertoire of peptides presented by cells which downregulate TAP can be targeted as a therapeutic strategy to mobilize a TAP-independent CD8 T cell response. Lastly, we discuss TAP polymorphisms and the role of TAP in inherited disorders.


Assuntos
Membro 2 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/metabolismo , Membro 3 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/metabolismo , Transportadores de Cassetes de Ligação de ATP/metabolismo , Apresentação de Antígeno/imunologia , Apresentação Cruzada/imunologia , Evasão Tumoral/imunologia , Membro 2 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/genética , Membro 3 da Subfamília B de Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/genética , Células Dendríticas/imunologia , Retículo Endoplasmático/metabolismo , Humanos , Complexo Principal de Histocompatibilidade/imunologia , Neoplasias/imunologia , Transporte Proteico/genética , Linfócitos T Citotóxicos/imunologia , Vírus/imunologia
5.
Curr Protoc Immunol ; 131(1): e115, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-33316130

RESUMO

Cross-presentation was first observed serendipitously in the 1970s. The importance of it was quickly realized and subsequently attracted great attention from immunologists. Since then, our knowledge of the ability of certain antigen presenting cells to internalize, process, and load exogenous antigens onto MHC-I molecules to cross-prime CD8+ T cells has increased significantly. Dendritic cells (DCs) are exceptional cross-presenters, thus making them a great tool to study cross-presentation but the relative rarity of DCs in circulation and in tissues makes it challenging to isolate sufficient numbers of cells to study this process in vitro. In this paper, we describe in detail two methods to culture DCs from bone-marrow progenitors and a method to expand the numbers of DCs present in vivo as a source of endogenous bona-fide cross-presenting DCs. We also describe methods to assess cross-presentation by DCs using the activation of primary CD8+ T cells as a readout. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Isolation of bone marrow progenitor cells Basic Protocol 2: In vitro differentiation of dendritic cells with GM-CSF Support Protocol 1: Preparation of conditioned medium from GM-CSF producing J558L cells Basic Protocol 3: In vitro differentiation of dendritic cells with Flt3L Support Protocol 2: Preparation of Flt3L containing medium from B16-Flt3L cells Basic Protocol 4: Expansion of cDC1s in vivo for use in ex vivo experiments Basic Protocol 5: Characterizing resting and activated dendritic cells Basic Protocol 6: Dendritic cell stimulation, antigenic cargo, and fixation Support Protocol 3: Preparation of model antigen coated microbeads Support Protocol 4: Preparation of apoptotic cells Support Protocol 5: Preparation of recombinant bacteria Basic Protocol 7: Immunocytochemistry immunofluorescence (ICC/IF) Support Protocol 6: Preparation of Alcian blue-coated coverslips Basic Protocol 8: CD8+ T cell activation to assess cross-presentation Support Protocol 7: Isolation and labeling of CD8+ T cells with CFSE.


Assuntos
Linfócitos T CD8-Positivos/imunologia , Apresentação Cruzada/imunologia , Células Dendríticas/citologia , Animais , Células da Medula Óssea/citologia , Técnicas de Cultura de Células , Diferenciação Celular , Proliferação de Células , Células Dendríticas/metabolismo , Humanos , Ativação Linfocitária , Camundongos , Microesferas
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