Rituximab (RTX) plus chemotherapy (R-CHOP) applied as a first-line therapy for lymphoma leads to a relapse in approximately 40% of the patients. Therefore, novel approaches to treat aggressive lymphomas are being intensively investigated. Several RTX-resistant (RR) cell lines have been established as surrogate models to study resistance to R-CHOP. Our study reveals that RR cells are characterized by a major downregulation of CD37, a molecule currently explored as a target for immunotherapy. Using CD20 knockout (KO) cell lines, we demonstrate that CD20 and CD37 form a complex, and hypothesize that the presence of CD20 stabilizes CD37 in the cell membrane. Consequently, we observe a diminished cytotoxicity of anti-CD37 monoclonal antibody (mAb) in complement-dependent cytotoxicity in both RR and CD20 KO cells that can be partially restored upon lysosome inhibition. On the other hand, the internalization rate of anti-CD37 mAb in CD20 KO cells is increased when compared to controls, suggesting unhampered efficacy of antibody drug conjugates (ADCs). Importantly, even a major downregulation in CD37 levels does not hamper the efficacy of CD37-directed chimeric antigen receptor (CAR) T cells. In summary, we present here a novel mechanism of CD37 regulation with further implications for the use of anti-CD37 immunotherapies.

• MeSH
• antigeny CD20 * imunologie   metabolismus   genetika   MeSH
• antigeny nádorové imunologie   genetika   MeSH
• B-buněčný lymfom * imunologie   terapie   genetika   farmakoterapie   MeSH
• chemorezistence účinky léků   MeSH
• chimerické antigenní receptory imunologie   genetika   metabolismus   MeSH
• cyklofosfamid farmakologie   terapeutické užití   MeSH
• doxorubicin farmakologie   aplikace a dávkování   MeSH
• imunoterapie * metody   MeSH
• lidé MeSH
• monoklonální protilátky farmakologie   terapeutické užití   MeSH
• nádorové buněčné linie MeSH
• protokoly antitumorózní kombinované chemoterapie farmakologie   terapeutické užití   MeSH
• regulace genové exprese u nádorů MeSH
• rituximab * farmakologie   terapeutické užití   MeSH
• tetraspaniny * genetika   metabolismus   MeSH
• vinkristin farmakologie   terapeutické užití   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

In the effort to improve immunophenotyping and minimal residual disease (MRD) assessment in acute lymphoblastic leukemia (ALL), the international Berlin-Frankfurt-Münster (iBFM) Flow Network introduced the myelomonocytic marker CD371 for a large prospective characterization with a long follow-up. In the present study, we aimed to investigate the clinical and biological features of CD371-positive (CD371pos) pediatric B-cell precursor ALL (BCP-ALL). From June 2014 to February 2017, 1812 pediatric patients with newly diagnosed BCP-ALLs enrolled in trial AIEOP-BFM ALL 2009 were evaluated as part of either a screening (n = 843, Italian centers) or validation cohort (n = 969, other iBFM centers). Laboratory assessment at diagnosis consisted of morphological, immunophenotypic, and genetic analysis. Response assessment relied on morphology, multiparametric flow cytometry (MFC), and polymerase chain reaction (PCR)-MRD. At diagnosis, 160 of 1812 (8.8%) BCP-ALLs were CD371pos. This correlated with older age, lower ETV6::RUNX1 frequency, immunophenotypic immaturity (all P < .001), and strong expression of CD34 and of CD45 (P < .05). During induction therapy, CD371pos BCP-ALLs showed a transient myelomonocytic switch (mm-SW: up to 65.4% of samples at day 15) and an inferior response to chemotherapy (slow early response, P < .001). However, the 5-year event-free survival was 88.3%. Among 420 patients from the validation cohort, 27 of 28 (96.4%) cases positive for DUX4-fusions were CD371pos. In conclusion, in the largest pediatric cohort, CD371 is the most sensitive marker of transient mm-SW, whose recognition is essential for proper MFC MRD assessment. CD371pos is associated to poor early treatment response, although a good outcome can be reached after MRD-based ALL-related therapies.

• MeSH
• buněčný rodokmen MeSH
• dítě MeSH
• imunofenotypizace MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• pre-B-buněčná leukemie * genetika   mortalita   farmakoterapie   patologie   diagnóza   terapie   metabolismus   MeSH
• předškolní dítě MeSH
• protokoly antitumorózní kombinované chemoterapie terapeutické užití   MeSH
• reziduální nádor * diagnóza   MeSH
• tetraspaniny genetika   metabolismus   MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH

Mast cells (MCs) are long-living immune cells highly specialized in the storage and release of different biologically active compounds and are involved in the regulation of innate and adaptive immunity. MC degranulation and replacement of MC granules are accompanied by active membrane remodelling. Tetraspanins represent an evolutionary conserved family of transmembrane proteins. By interacting with lipids and other membrane and intracellular proteins, they are involved in organisation of membrane protein complexes and act as "molecular facilitators" connecting extracellular and cytoplasmic signaling elements. MCs express different tetraspanins and MC degranulation is accompanied by changes in membrane organisation. Therefore, tetraspanins are very likely involved in the regulation of MC exocytosis and membrane reorganisation after degranulation. Antiviral response and production of exosomes are further aspects of MC function characterized by dynamic changes of membrane organization. In this review, we pay a particular attention to tetraspanin gene expression in different human and murine MC populations, discuss tetraspanin involvement in regulation of key MC signaling complexes, and analyze the potential contribution of tetraspanins to MC antiviral response and exosome production. In-depth knowledge of tetraspanin-mediated molecular mechanisms involved in different aspects of the regulation of MC response will be beneficial for patients with allergies, characterized by overwhelming MC reactions.

• MeSH
• degranulace buněk MeSH
• exozómy metabolismus   MeSH
• lidé MeSH
• mastocyty imunologie   metabolismus   MeSH
• myši MeSH
• signální transdukce MeSH
• tetraspaniny genetika   imunologie   metabolismus   MeSH
• virové nemoci imunologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

A disintegrin and metalloproteinase 10 (ADAM10) plays a major role in the ectodomain shedding of important surface molecules with physiological and pathological relevance including the amyloid precursor protein (APP), the cellular prion protein, and different cadherins. Despite its therapeutic potential, there is still a considerable lack of knowledge how this protease is regulated. We have previously identified tetraspanin15 (Tspan15) as a member of the TspanC8 family to specifically associate with ADAM10. Cell-based overexpression experiments revealed that this binding affected the maturation process and surface expression of the protease. Our current study shows that Tspan15 is abundantly expressed in mouse brain, where it specifically interacts with endogenous ADAM10. Tspan15 knockout mice did not reveal an overt phenotype but showed a pronounced decrease of the active and mature form of ADAM10, an effect which augmented with aging. The decreased expression of active ADAM10 correlated with an age-dependent reduced shedding of neuronal (N)-cadherin and the cellular prion protein. APP α-secretase cleavage and the expression of Notch-dependent genes were not affected by the loss of Tspan15, which is consistent with the hypothesis that different TspanC8s cause ADAM10 to preferentially cleave particular substrates. Analyzing spine morphology revealed no obvious differences between Tspan15 knockout and wild-type mice. However, Tspan15 expression was elevated in brains of an Alzheimer's disease mouse model and of patients, suggesting that upregulation of Tspan15 expression reflects a cellular response in a disease state. In conclusion, our data show that Tspan15 and most likely also other members of the TspanC8 family are central modulators of ADAM10-mediated ectodomain shedding in vivo.

• MeSH
• Alzheimerova nemoc genetika   metabolismus   MeSH
• krysa rodu rattus MeSH
• kultivované buňky MeSH
• lidé MeSH
• mozek metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• neurony metabolismus   MeSH
• protein ADAM10 genetika   metabolismus   MeSH
• regulace genové exprese * MeSH
• stanovení celkové genové exprese metody   MeSH
• synapse metabolismus   MeSH
• tetraspaniny genetika   metabolismus   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Despite existing knowledge about the role of the A Disintegrin and Metalloproteinase 10 (ADAM10) as the α-secretase involved in the non-amyloidogenic processing of the amyloid precursor protein (APP) and Notch signalling we have only limited information about its regulation. In this study, we have identified ADAM10 interactors using a split ubiquitin yeast two hybrid approach. Tetraspanin 3 (Tspan3), which is highly expressed in the murine brain and elevated in brains of Alzheimer´s disease (AD) patients, was identified and confirmed to bind ADAM10 by co-immunoprecipitation experiments in mammalian cells in complex with APP and the γ-secretase protease presenilin. Tspan3 expression increased the cell surface levels of its interacting partners and was mainly localized in early and late endosomes. In contrast to the previously described ADAM10-binding tetraspanins, Tspan3 did not affect the endoplasmic reticulum to plasma membrane transport of ADAM10. Heterologous Tspan3 expression significantly increased the appearance of carboxy-terminal cleavage products of ADAM10 and APP, whereas N-cadherin ectodomain shedding appeared unaffected. Inhibiting the endocytosis of Tspan3 by mutating a critical cytoplasmic tyrosine-based internalization motif led to increased surface expression of APP and ADAM10. After its downregulation in neuroblastoma cells and in brains of Tspan3-deficient mice, ADAM10 and APP levels appeared unaltered possibly due to a compensatory increase in the expression of Tspans 5 and 7, respectively. In conclusion, our data suggest that Tspan3 acts in concert with other tetraspanins as a stabilizing factor of active ADAM10, APP and the γ-secretase complex at the plasma membrane and within the endocytic pathway.

• MeSH
• amyloidový prekurzorový protein beta genetika   metabolismus   MeSH
• buněčná membrána metabolismus   MeSH
• endocytóza MeSH
• endozomy chemie   metabolismus   MeSH
• HEK293 buňky MeSH
• kadheriny genetika   metabolismus   MeSH
• lidé MeSH
• membránové proteiny genetika   metabolismus   MeSH
• mozek - chemie MeSH
• mozek metabolismus   MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• neurony cytologie   metabolismus   MeSH
• preseniliny genetika   metabolismus   MeSH
• protein ADAM10 genetika   metabolismus   MeSH
• proteiny nervové tkáně genetika   metabolismus   MeSH
• receptory Notch genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• sekretasy genetika   metabolismus   MeSH
• signální transdukce MeSH
• techniky dvojhybridového systému MeSH
• tetraspaniny genetika   metabolismus   MeSH
• transport proteinů MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Mast cells are powerful immune modulators of the tissue microenvironment. Within seconds of activation, these cells release a variety of preformed biologically active products, followed by a wave of mediator synthesis and secretion. Increasing evidence suggests that an intricate network of inhibitory and activating receptors, specific signaling pathways, and adaptor proteins governs mast cell responsiveness to stimuli. Here, we discuss the biological and clinical relevance of negative and positive signaling modalities that control mast cell activation, with an emphasis on novel FcεRI regulators, immunoglobulin E (IgE)-independent pathways [e.g., Mas-related G protein-coupled receptor X2 (MRGPRX2)], tetraspanins, and the CD300 family of inhibitory and activating receptors.

• MeSH
• antigen Ki-1 metabolismus   MeSH
• degranulace buněk * MeSH
• imunomodulace MeSH
• kationické antimikrobiální peptidy metabolismus   MeSH
• lidé MeSH
• mastocyty imunologie   MeSH
• neuropeptidy metabolismus   MeSH
• proteiny nervové tkáně metabolismus   MeSH
• receptory IgE metabolismus   MeSH
• receptory neuropeptidů metabolismus   MeSH
• receptory spřažené s G-proteiny metabolismus   MeSH
• signální transdukce * MeSH
• spinální ganglia metabolismus   MeSH
• tetraspaniny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Fertilization process is a very clever and unique process comprising some essential steps resulting in formation of zygote. Tetraspanin CD9 is considered to be a serious candidate molecule participating in these events. The importance of CD9 has been discussed in relation to acrosome reaction, sperm-binding, sperm-penetration, sperm-egg fusion and eventually, egg activation. The abundant expression of CD9 oocyte plasma membrane and the presence of CD9-containing vesicles in the perivitelline space of intact oocytes have been confirmed. Despite the fact that majority of authors analyzed CD9 expressed on oocytes, several studies considered the function of sperm CD9, too. To understand CD9 involvement, various conditions of in vitro fertilization (IVF) assays using polyclonal as well as monoclonal antibodies or knockout mice were carried out. However, ambiguous data have been obtained about the importance of CD9 in sperm-egg binding or fusion. Although the current findings did not prove any hypothesis, the indispensable role of CD9 in fertilization process was not excluded and the precise role of CD9 remains unexplained.

• MeSH
• antigeny CD9 metabolismus   MeSH
• fertilizace fyziologie   MeSH
• lidé MeSH
• oocyty fyziologie   MeSH
• savci MeSH
• spermie fyziologie   MeSH
• tetraspaniny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH

Tetraspanins are integral membrane proteins that function as organizers of multimolecular complexes and modulate function of associated proteins. Mammalian genomes encode approximately 30 different members of this family and remotely related eukaryotic species also contain conserved tetraspanin homologs. Tetraspanins are involved in a number of fundamental processes such as regulation of cell migration, fusion, immunity and signaling. Moreover, they are implied in numerous pathological states including mental disorders, infectious diseases or cancer. Despite the great interest in tetraspanins, the structural and biochemical basis of their activity is still largely unknown. A major bottleneck lies in the difficulty of obtaining stable and homogeneous protein samples in large quantities. Here we report expression screening of 15 members of the human tetraspanin superfamily and successful protocols for the production in S. cerevisiae of a subset of tetraspanins involved in human cancer development. We have demonstrated the subcellular localization of overexpressed tetraspanin-green fluorescent protein fusion proteins in S. cerevisiae and found that despite being mislocalized, the fusion proteins are not degraded. The recombinantly produced tetraspanins are dispersed within the endoplasmic reticulum membranes or localized in granule-like structures in yeast cells. The recombinantly produced tetraspanins can be extracted from the membrane fraction and purified with detergents or the poly (styrene-co-maleic acid) polymer technique for use in further biochemical or biophysical studies.

• MeSH
• glykosylace MeSH
• konfokální mikroskopie MeSH
• lidé MeSH
• rekombinantní fúzní proteiny genetika   metabolismus   MeSH
• Saccharomyces cerevisiae genetika   metabolismus   MeSH
• subcelulární frakce MeSH
• tetraspaniny genetika   metabolismus   MeSH
• transport proteinů MeSH
• zelené fluorescenční proteiny genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

The mechanism of gamete fusion remains largely unknown on a molecular level despite its indisputable significance. Only a few of the molecules required for membrane interaction are known, among them IZUMO1, which is present on sperm, tetraspanin CD9, which is present on the egg, and the newly found oolema protein named Juno. A concept of a large multiprotein complex on both membranes forming fusion machinery has recently emerged. The Juno and IZUMO1, up to present, is the only known extracellular receptor pair in the process of fertilization, thus, facilitating the essential binding of gametes. However, neither IZUMO1 nor Juno appears to be the fusogenic protein. At the same time, the tetraspanin is expected to play a role in organizing the egg membrane order and to interact laterally with other factors. This review summarizes, to present, the known molecules involved in the process of sperm-egg fusion. The complexity and expected redundancy of the involved factors makes the process an intricate and still poorly understood mechanism, which is difficult to comprehend in its full distinction.

• MeSH
• fertilizace fyziologie   MeSH
• imunoglobuliny metabolismus   MeSH
• integriny metabolismus   MeSH
• lidé MeSH
• membránové proteiny metabolismus   MeSH
• ovum metabolismus   MeSH
• proteiny semenné plazmy metabolismus   MeSH
• receptory buněčného povrchu metabolismus   MeSH
• spermie metabolismus   MeSH
• tetraspaniny metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH