Project description:The capacity of dendritic cells (DC) to migrate from peripheral organs to lymph nodes (LN) is an important event in the initiation of a T cell-mediated immune response. Previously it was shown that the ATP-binding cassette (ABC) transporters P-glycoprotein (P-gp; ABCB1) and the 2 multidrug resistance protein 1 (MRP1; ABCC1) play a role in both human and murine DC migration. Here we show that a more recently discovered family-member, MRP4 (ABCC4) is expressed on both epidermal and dermal human skin DC and contributes to the migratory capacity of DC. Pharmacological inhibition of MRP4 activity or down-regulation through RNAi in DC resulted in reduced migration of DC from human skin explants and of in vitro generated Langerhans cells. The responsible MRP4 substrate remains to be identified as exogenous addition of MRP4’s known substrates PGE2, leukotriene B4 and D4 or cyclic nucleotides (all previously implicated in DC migration) could not restore migration. This notwithstanding, our data show that MRP4 is an important molecule, significantly contributing to human DC migration towards the draining lymph nodes, and thereby relevant for the initiation of an immune response and a possible target for immunotherapy. Keywords: cell type comparison, RNAi knockdown for MRP4 2 samples were analyzed to compare. Immature DC cultured from MUTZ3 (reference control) or from MUTZ3-shMRP4 cells
Project description:The capacity of dendritic cells (DC) to migrate from peripheral organs to lymph nodes (LN) is an important event in the initiation of a T cell-mediated immune response. Previously it was shown that the ATP-binding cassette (ABC) transporters P-glycoprotein (P-gp; ABCB1) and the 2 multidrug resistance protein 1 (MRP1; ABCC1) play a role in both human and murine DC migration. Here we show that a more recently discovered family-member, MRP4 (ABCC4) is expressed on both epidermal and dermal human skin DC and contributes to the migratory capacity of DC. Pharmacological inhibition of MRP4 activity or down-regulation through RNAi in DC resulted in reduced migration of DC from human skin explants and of in vitro generated Langerhans cells. The responsible MRP4 substrate remains to be identified as exogenous addition of MRP4’s known substrates PGE2, leukotriene B4 and D4 or cyclic nucleotides (all previously implicated in DC migration) could not restore migration. This notwithstanding, our data show that MRP4 is an important molecule, significantly contributing to human DC migration towards the draining lymph nodes, and thereby relevant for the initiation of an immune response and a possible target for immunotherapy. Keywords: cell type comparison, RNAi knockdown for MRP4
Project description:The role of ABCC4, an ATP-binding cassette transporter, in the process of platelet formation, megakaryopoiesis, is unknown. Here, we show that ABCC4 is highly expressed in megakaryocytes (MKs). Mining of public genomic data (ATAC-seq and genome wide chromatin interactions, Hi-C) revealed that key megakaryopoiesis transcription factors (TFs) interacted with ABCC4 regulatory elements and likely accounted for high ABCC4 expression in MKs. Importantly these genomic interactions for ABCC4 ranked higher than for genes with known roles in megakaryopoiesis suggesting a role for ABCC4 in megakaryopoiesis. We then demonstrate that ABCC4 is required for optimal platelet formation as in vitro differentiation of fetal liver derived MKs from Abcc4-/- mice exhibited impaired proplatelet formation and polyploidization, features required for optimal megakaryopoiesis. Likewise, a human megakaryoblastic cell line, MEG-01 showed that acute ABCC4 inhibition markedly suppressed key processes in megakaryopoiesis and that these effects were related to reduced cAMP export and enhanced dissociation of a negative regulator of megakaryopoiesis, protein kinase A (PKA) from ABCC4. PKA activity concomitantly increased after ABCC4 inhibition which was coupled with significantly reduced GATA-1 expression, a TF needed for optimal megakaryopoiesis. Further, ABCC4 protected MKs from 6-mercaptopurine (6-MP) as Abcc4-/- mice show a profound reduction in MKs after 6-MP treatment. In total, our studies show that ABCC4 not only protects the MKs but is also required for maximal platelet production from MKs, suggesting modulation of ABCC4 function might be a potential therapeutic strategy to regulate platelet production.
Project description:The role of ABCC4, an ATP-binding cassette transporter, in the process of platelet formation, megakaryopoiesis, is unknown. Here, we show that ABCC4 is highly expressed in megakaryocytes (MKs). Mining of public genomic data (ATAC-seq and genome wide chromatin interactions, Hi-C) revealed that key megakaryopoiesis transcription factors (TFs) interacted with ABCC4 regulatory elements and likely accounted for high ABCC4 expression in MKs. Importantly these genomic interactions for ABCC4 ranked higher than for genes with known roles in megakaryopoiesis suggesting a role for ABCC4 in megakaryopoiesis. We then demonstrate that ABCC4 is required for optimal platelet formation as in vitro differentiation of fetal liver derived MKs from Abcc4-/- mice exhibited impaired proplatelet formation and polyploidization, features required for optimal megakaryopoiesis. Likewise, a human megakaryoblastic cell line, MEG-01 showed that acute ABCC4 inhibition markedly suppressed key processes in megakaryopoiesis and that these effects were related to reduced cAMP export and enhanced dissociation of a negative regulator of megakaryopoiesis, protein kinase A (PKA) from ABCC4. PKA activity concomitantly increased after ABCC4 inhibition which was coupled with significantly reduced GATA-1 expression, a TF needed for optimal megakaryopoiesis. Further, ABCC4 protected MKs from 6-mercaptopurine (6-MP) as Abcc4-/- mice show a profound reduction in MKs after 6-MP treatment. In total, our studies show that ABCC4 not only protects the MKs but is also required for maximal platelet production from MKs, suggesting modulation of ABCC4 function might be a potential therapeutic strategy to regulate platelet production.
Project description:Chemotherapy resistance supposes a challenge for cancer treatment. Multidrug efflux pumps are able to extrude chemotherapeutic agents increasing their resistance to the treatment. Ptch1 is overexpressed in many metastatic cancers, where it acts as a multidrug efflux pump. Indeed, Ptch1 strongly contributes to the drug efflux in H295R, a human adrenal carcinoma cell line. This efflux is coupled to the proton motive force, restricting Ptch1 drug efflux to acidify environments like cancers. Even though Ptch1 is overexpressed in H295R cells, only 1% of these cells present Ptch1 at the cell surface (Ptch1 positive or PTC subpopulation ). We showed that these Ptch1 positive cells had an increased chemotherapy resistance, migration and clonogenicity compared to the parental cell lines. The RNA seq analysis performed on H295R Ptch1 positive cells and parental H295R cells show an increase of the expression of genes involved in the Hedgehog signaling such as Ptch1, of genes involved in EMT and drug resistance, and of genes involved in stem cell maintenance suggesting that these cells could be cancer stem cells.
Project description:Colorectal carcinoma (CRC) is the third most common malignancy worldwide. In Egypt, the relative frequency of CRC is about 9-12% with high male predominance 3:1. The high mortality rates associated with CRC is reflective of several factors including: the lack of apparent symptoms in the early stages and the absence of cancer prevention strategies in developing countries.
Insulin-like growth factor II m-RNA-binding protein 3 (IMP3) is a member of the IMP family which plays a key role in the transfer and stabilization of mRNA, cell growth, and migration during embryogenesis. IMP3 has gained considerable interest as a cancer-associated protein. Previous studies strongly suggest that IMP3 may represent a valuable prognostic marker in human cancer. Its overexpression has been reported in a variety of human types of cancer, including lung cancer, colon cancer, pancreatic cancer, gastric cancer, liver cancer, and breast cancer
Project description:Staphylococcus aureus can infect a wide range of animals and pose as a serious threat to public health by transferring via animals or animal-derived food stuff. Even more importantly, multiple drug resistance development in the bacteria has resulted in therapeutic failure of a number of antibiotics. Therefore by realizing the need of time, this study was designed to investigate the underlying mechanisms of virulence and resistance in S. aureus. After screening through in vivo and in vitro virulence assays and susceptibility test, a highly virulent and multidrug resistant MRSA strain was selected for differential analysis by RNA-seq technology and gene expression results were verified by RT-qPCR. Up-regulation of crucial regulators like sarA and KdpDE seemed to play role in decreased expression of many exotoxin genes while enhanced the adhesion and cell wall protein expression, leading to strong biofilm production in the presence of inactivated agr system. In addition to resistance genes like blaZ, ermC and femA, up-regulation of vraS and multidrug ABC transporter genes contributed to the multidrug resistance in MRSA. Fluoroquinolone resistance was attributed to mutational changes in gyrA and parC genes. Our findings suggested that many virulence and resistance determinants in S. aureus are controlled by complex network of various regulators, and sarA is the most important of those as it adds to pathogenicity of the bacteria and ensures its survival in diverse environment. Further investigations are required to unveil these mechanisms in S. aureus. Four samples were analysed including 2 MRSA1679a test strain and 2 reference strain ATCC1 samples with two replicates of each.
Project description:Expression data from dendritic cell subsets derived or sorted from control littermate and CD11c-Cre/BRAFV600E(flox-CA) mice Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasia characterized by granulomatous lesions containing pathological CD207+ dendritic cells (DCs) with constitutively activated mitogen-activated protein kinase (MAPK) pathway signaling. Approximately 60% of LCH patients harbor somatic BRAFV600E mutations localizing to CD207+ DCs within lesions. However, the mechanisms driving BRAFV600E+ LCH cell accumulation in lesions remain unknown. Here we show that sustained extracellular signal–related kinase activity induced by BRAFV600E inhibits C-C motif chemokine receptor 7 (CCR7)–mediated DC migration, trapping DCs in tissue lesions. Additionally, BRAFV600E increases expression of BCL2-like protein 1 (BCL2L1) in DCs, resulting in resistance to apoptosis. Pharmacological MAPK inhibition restores migration and apoptosis potential in a mouse LCH model, as well as in primary human LCH cells. We also demonstrate that MEK inhibitor-loaded nanoparticles have the capacity to concentrate drug delivery to phagocytic cells, significantly reducing off-target toxicity. Collectively, our results indicate that MAPK tightly suppresses DC migration and augments DC survival, rendering DCs in LCH lesions trapped and resistant to cell death.
Project description:Multidrug resistance in the pathogenic fungus Candida glabrata is a growing global threat. Here, we study mechanisms of multidrug resistance in this pathogen. Exposure of C. glabrata cells to micafungin (an echinocandin) leads to the isolation of a mutant exhibiting resistance to echinocandin and azole antifungals. The drug-resistant phenotype is due to a non-synonymous mutation (R70H) in gene IPI1, which is known to be involved in pre-rRNA processing in Saccharomyces cerevisiae. Azole resistance in the ipi1-R70H mutant depends on the Pdr1 transcription factor, which regulates the expression of multidrug transporters. We show that the C. glabrata Ipi1 protein physically interacts with the ribosome-related chaperones Ssb and Ssz1, both of which bind to Pdr1. The Ipi1-Ssb/Ssz1 complex inhibits Pdr1-mediated gene expression and multidrug resistance in C. glabrata, in contrast to S. cerevisiae where Ssz1 has been shown to act as a positive regulator of Pdr1. Furthermore, micafungin exposure reduces metabolic activity and cell proliferation in the ipi1-R70H mutant, which may contribute to micafungin tolerance.
Project description:The number and overlapping substrate repertoire of multidrug efflux pumps in the E. coli genome suggest a physiological role apart from multidrug resistance. This role was investigated using transcriptomic analyses of cDNAs labeled from E. coli AG102 mRNA (hyper drug resistant, marR1) and its isogenic major efflux pump mutants. Keywords: Mutation Analysis