RESUMO
The role of extracellular vesicles (EVs) proteome in diffuse large B-cell lymphoma (DLBCL) pathology, subclassification, and patient screening is unexplored. We analyzed by state-of-the-art mass spectrometry the whole cell and secreted extracellular vesicles (EVs) proteomes of different molecular subtypes of DLBCL, germinal center B cell (GCB subtype), and activated B cell (ABC subtype). After quality control assessment, we compared whole-cell and secreted EVs proteomes of the two cell-of-origin (COO) categories, GCB and ABC subtypes, resulting in 288/1115 significantly differential expressed proteins from the whole-cell proteome and 228/608 proteins from EVs (adjust p-value < 0.05/p-value < 0.05). In our preclinical model system, we demonstrated that the EV proteome and the whole-cell proteome possess the capacity to separate cell lines into ABC and GCB subtypes. KEGG functional analysis and GO enrichment analysis for cellular component, molecular function, and biological process of differential expressed proteins (DEP) between ABC and GCB EVs showed a significant enrichment of pathways involved in immune response function. Other enriched functional categories for DEPs constitute cellular signaling and intracellular trafficking such as B-cell receptor (BCR), Fc_gamma R-mediated phagocytosis, ErbB signaling, and endocytosis. Our results suggest EVs can be explored as a tool for patient diagnosis, follow-up, and disease monitoring. Finally, this study proposes novel drug targets based on highly expressed proteins, for which antitumor drugs are available suggesting potential combinatorial therapies for aggressive forms of DLBCL. Data are available via ProteomeXchange with identifier PXD028267.
Assuntos
Vesículas Extracelulares/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Proteoma/análise , Proteômica/métodos , Linfócitos B/metabolismo , Linhagem Celular Tumoral , Centro Germinativo/citologia , Centro Germinativo/metabolismo , Humanos , Linfoma Difuso de Grandes Células B/metabolismo , Espectrometria de MassasRESUMO
Proteome maintenance in contracting skeletal and cardiac muscles depends on the chaperone-regulating protein BAG3. Reduced BAG3 activity leads to muscle weakness and heart failure in animal models and patients. BAG3 and its chaperone partners recognize mechanically damaged muscle proteins and initiate their disposal through chaperone-assisted selective autophagy (CASA). However, molecular details of the force-dependent regulation of BAG3 have remained elusive so far. Here, we demonstrate that mechanical stress triggers the dephosphorylation of BAG3 in human muscle and in isolated cells. We identify force-regulated phospho-switches in BAG3 that control CASA complex assembly and CASA activity. Differential proteomics reveal RAB GTPases, which organize membrane traffic and fusion, as dephosphorylation-dependent interactors of BAG3. In fact, RAB7A and RAB11B are shown here to be essential for CASA in skeletal muscle cells. Moreover, BAG3 dephosphorylation is also observed upon induction of mitophagy, suggesting an involvement of the cochaperone in the RAB7A-dependent autophagic engulfment of damaged mitochondria in exercised muscle. Cooperation of BAG3 with RAB7A relies on a direct interaction of both proteins, which is regulated by the nucleotide state of the GTPase and by association with the autophagosome membrane protein LC3B. Finally, we provide evidence that BAG3 and RAB7A also cooperate in non-muscle cells and propose that overactivation of CASA in RAB7A-L129F patients contributes to the loss of peripheral neurons in Charcot-Marie-Tooth neuropathy.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Proteínas Reguladoras de Apoptose , Proteínas rab de Ligação ao GTP , proteínas de unión al GTP Rab7 , Humanos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas Reguladoras de Apoptose/genética , Fosforilação , Proteínas rab de Ligação ao GTP/metabolismo , Proteínas rab de Ligação ao GTP/genética , proteínas de unión al GTP Rab7/metabolismo , Proteostase , Proteínas Associadas aos Microtúbulos/metabolismo , Proteínas Associadas aos Microtúbulos/genética , Músculo Esquelético/metabolismo , Autofagia/fisiologia , Animais , Camundongos , Transporte ProteicoRESUMO
Through lateral transfer, extra-cellular vesicles (EVs) transport their DNA, miRNA, mRNA and proteins such as enzymes mediating drug resistance, transporters as well as growth factors to neighboring cells. By virtue of this horizontal transfer, EVs potentially regulate cell growth, migration, angiogenesis and metastasis and increase tissue permeability in cancer. Furthermore, EVs regulate immune factors and allow the tumor cells to evade immune recognition and cell death. To explore if the proteomes of exosomes support functional transfer of cancer hallmarks, in this meta-analysis, we compared EVs and whole cell proteomes from the NCI-60 human tumor cell line panel. We observed a subgroup of proteins in each cancer hallmark signature as highly abundant and consistently expressed in EVs from all cell lines. Among these were oncoproteins frequently targeted in cancer therapies whose presence on EVs could potentially render therapies less effective by serving as decoys.