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Missing in Metastasis (MIM),or Metastasis Suppressor 1 (MTSS1),is a highly conserved protein,which links the plasma membrane to the actin cytoskeleton. MIM has been implicated in various cancers,however,its modes of action remain largely enigmatic. Here,we performed an extensive in silico characterisation of MIM to gain better understanding of its function. We detected previously unappreciated functional motifs including adaptor protein (AP) complex interaction site and a C-helix,pointing to a role in endocytosis and regulation of actin dynamics,respectively. We also identified new functional regions,characterised with phosphorylation sites or distinct hydrophilic properties. Strong negative selection during evolution,yielding high conservation of MIM,has been combined with positive selection at key sites. Interestingly,our analysis of intra-molecular co-evolution revealed potential regulatory hotspots that coincided with reduced potentially pathogenic polymorphisms. We explored databases for the mutations and expression levels of MIM in cancer. Experimentally,we focused on chronic lymphocytic leukaemia (CLL),where MIM showed high overall expression,however,downregulation on poor prognosis samples. Finally,we propose strong conservation of MTSS1 also on the transcriptional level and predict novel transcriptional regulators. Our data highlight important targets for future studies on the role of MIM in different tissues and cancers. View Publication

Aquaporin (AQP) 3 expression is altered in inflammatory bowel diseases,although the exact mechanisms regulating AQP abundance are unclear. Although interferon gamma (IFNgamma) is centrally involved in intestinal inflammation,the effect of this cytokine on AQP3 expression remains unknown. HT-29 human colonic epithelial cells were treated with IFNgamma to assess AQP3 mRNA expression by real-time RT-PCR and functional protein expression through the uptake of radiolabelled glycerol. Transient knockdown of signal transducer and activator of transcription 1 (STAT1),STAT3,Sp1,and Sp3 were performed to determine the involvement of these transcription factors in the IFNgamma-induced signalling cascade. AQP3 promoter regions involved in the response to IFNgamma were assessed using a luciferase reporter system. Likewise,enteroids derived from human colonic biopsies were also treated with IFNgamma to assess for changes in AQP3 mRNA expression. IFNgamma decreased AQP3 mRNA expression in HT-29 cells in a time- and concentration-dependent manner and reduced functional AQP3 protein expression (decreased 3H-labelled glycerol uptake). IFNgamma also reduced AQP3 expression in enteroids derived from human colonic biopsies. Knockdown of STAT1 partially prevented the IFNgamma-induced downregulation of AQP3 expression,whereas STAT3 and Sp3 knockdowns resulted in increased baseline expression of AQP3 but did not alter IFNgamma-induced downregulation. Constitutive transcription of AQP3 is downregulated by IFNgamma as demonstrated using the luciferase reporter system,with Sp3 bound to the AQP3 promoter as shown by chromatin immunoprecipitation. AQP3 constitutive transcription in intestinal epithelial cells is downregulated by IFNgamma. This response requires STAT1 that is postulated to drive the downregulation of AQP3 expression through increased acetylation or decreased deacetylation the AQP3 promoter,ultimately resulting in decreased constitutive transcription of AQP3. KEY MESSAGES • IFNgamma suppresses the expression of AQP3 in intestinal epithelial cells. • Proximal AQP3 promoter elements are sufficient to drive constitutive expression and mediate the IFNgamma-induced downregulation of AQP3 mRNA expression. • IFNgamma-induced suppression of AQP3 is dependent upon STAT1 expression,but not STAT3,Sp1,or Sp3. View Publication

Gene correction in human long-term hematopoietic stem cells (LT-HSCs) could be an effective therapy for monogenic diseases of the blood and immune system. Here we describe an approach for X-linked sSevere cCombined iImmunodeficiency (SCID-X1) using targeted integration of a cDNA into the endogenous start codon to functionally correct disease-causing mutations throughout the gene. Using a CRISPR-Cas9/AAV6 based strategy,we achieve up to 20{\%} targeted integration frequencies in LT-HSCs. As measures of the lack of toxicity we observe no evidence of abnormal hematopoiesis following transplantation and no evidence of off-target mutations using a high-fidelity Cas9 as a ribonucleoprotein complex. We achieve high levels of targeting frequencies (median 45{\%}) in CD34+ HSPCs from six SCID-X1 patients and demonstrate rescue of lymphopoietic defect in a patient derived HSPC population in vitro and in vivo. In sum,our study provides specificity,toxicity and efficacy data supportive of clinical development of genome editing to treat SCID-Xl. View Publication

BACKGROUND It is clinically important to maintain high viability and potency of umbilical cord blood units (CBUs) for transplantation during thawing. In the absence of a standard thawing protocol,this study was designed to develop one based on the consensus practice of transplant centers and address the shortage of dextran 40 thawing solution. STUDY DESIGN AND METHODS Frozen CBU aliquots were thawed using dextran 40 thawing solution while manipulating temperature and volume of diluent and mode of dilution. The effects of these on CD45+ and CD34+ cell viability were measured through annexin V and SYTOX green staining. The developed protocol was then used to compare dextran 40 and PLASMA-LYTE A thawing solutions and finally tested on whole CBUs. RESULTS Step-by-step investigations resulted in the development of a protocol that thaws and dilutes CBUs with room temperature diluent to five times the original volume using two sequential dilutions separated by equilibration times. PLASMA-LYTE A diluent provided superior viability of CD45+ and CD34+ cells than dextran 40 and recovered more colony-forming units. However,both diluents were equally effective in maintaining stability of the thawed CBU for 4 hours. Moreover,the stem cell-enriched CD34+CD38- subpopulations appeared more resistant to cryoinjuries than their CD34+CD38+ counterpart. CONCLUSION The developed thawing protocol recovers viable CD45+ and CD34+ cells above the standard thresholds and maintains CBU potency. PLASMA-LYTE A for thawing solution proved to be an efficient alternative to dextran 40. Finally,greater dilution should be avoided to maintain the viability of CD45+ cells and maximize graft cell dose. View Publication

Sickle cell disease (SCD) is a monogenic disorder that affects millions worldwide. Allogeneic hematopoietic stem cell transplantation is the only available cure. Here,we demonstrate the use of CRISPR/Cas9 and a short single-stranded oligonucleotide template to correct the sickle mutation in the beta-globin gene in hematopoietic stem and progenitor cells (HSPCs) from peripheral blood or bone marrow of patients with SCD,with 24.5 ± 7.6{\%} efficiency without selection. Erythrocytes derived from gene-edited cells showed a marked reduction of sickle cells,with the level of normal hemoglobin (HbA) increased to 25.3 ± 13.9{\%}. Gene-corrected SCD HSPCs retained the ability to engraft when transplanted into non-obese diabetic (NOD)-SCID-gamma (NSG) mice with detectable levels of gene correction 16-19 weeks post-transplantation. We show that,by using a high-fidelity SpyCas9 that maintained the same level of on-target gene modification,the off-target effects including chromosomal rearrangements were significantly reduced. Taken together,our results demonstrate efficient gene correction of the sickle mutation in both peripheral blood and bone marrow-derived SCD HSPCs,a significant reduction in sickling of red blood cells,engraftment of gene-edited SCD HSPCs in vivo and the importance of reducing off-target effects; all are essential for moving genome editing based SCD treatment into clinical practice. View Publication

Mucosal-associated invariant T (MAIT) cells exhibit different characteristics from those of TCRalpha7.2- conventional T cells. They play important roles in various inflammatory diseases,including rheumatoid arthritis and inflammatory bowel disease. MAIT cells express a single T cell receptor alpha chain,TCRalpha7.2 segment associated with Jalpha33 and CDR3 with fixed length,which recognizes bacteria-derived vitamin B metabolites. However,the characteristics of MAIT cells and TCRalpha7.2+ CD161- T cells have never been compared. Here,we performed RNA sequencing to compare the properties of MAIT cells,TCRalpha7.2- conventional T cells and TCRalpha7.2+ CD161- T cells. Genome-wide transcriptomes of MAIT cells,TCRalpha7.2- conventional T cells,and TCRalpha7.2+ CD161- T cells were compared and analyzed using causal network analysis. This is the first report comparing the transcriptomes of MAIT cells,TCRalpha7.2- conventional T cells and TCRalpha7.2+ CD161- T cells. We also identified the predominant signaling pathways of MAIT cells,which differed from those of TCRalpha7.2- conventional T cells and TCRalpha7.2+ CD161- T cells,through a gene set enrichment test and upstream regulator analysis and identified the genes responsible for the characteristic MAIT cell phenotypes. Our study advances the complete understanding of MAIT biology. View Publication

Acute myeloid leukemia (AML) is an aggressive clonal disorder of hematopoietic stem cells (HSCs) and primitive progenitors that blocks their myeloid differentiation,generating self-renewing leukemic stem cells (LSCs). Here,we show that the mRNA m6A reader YTHDF2 is overexpressed in a broad spectrum of human AML and is required for disease initiation as well as propagation in mouse and human AML. YTHDF2 decreases the half-life of diverse m6A transcripts that contribute to the overall integrity of LSC function,including the tumor necrosis factor receptor Tnfrsf2,whose upregulation in Ythdf2-deficient LSCs primes cells for apoptosis. Intriguingly,YTHDF2 is not essential for normal HSC function,with YTHDF2 deficiency actually enhancing HSC activity. Thus,we identify YTHDF2 as a unique therapeutic target whose inhibition selectively targets LSCs while promoting HSC expansion. View Publication

Hematopoiesis provides an accessible system for studying the principles underlying cell-fate decisions in stem cells. Proposed models of hematopoiesis suggest that quantitative changes in lineage-specific transcription factors (LS-TFs) underlie cell-fate decisions. However,evidence for such models is lacking as TF levels are typically measured via RNA expression rather than by analyzing temporal changes in protein abundance. Here,we used single-cell mass cytometry and absolute quantification by mass spectrometry to capture the temporal dynamics of TF protein expression in individual cells during human erythropoiesis. We found that LS-TFs from alternate lineages are co-expressed,as proteins,in individual early progenitor cells and quantitative changes of LS-TFs occur gradually rather than abruptly to direct cell-fate decisions. Importantly,upregulation of a megakaryocytic TF in early progenitors is sufficient to deviate cells from an erythroid to a megakaryocyte trajectory,showing that quantitative changes in protein abundance of LS-TFs in progenitors can determine alternate cell fates. View Publication

Background Cancer has been considered a serious global health problem and a leading cause of morbidity and mortality worldwide. Despite recent advances in cancer therapy,treatments of advance stage cancers are mostly ineffective resulting in poor survival of patients. Recent evidences suggest that multipotent human mesenchymal stem cells (hMSCs) play important roles in growth and metastasis of several cancers by enhancing their engraftment and inducing tumor neovascularization. However,the effect of hMSCs on cancer cells is still controversial because there are also evidences demonstrating that hMSCs inhibited growth and metastasis of some cancers. Methods In this study,we investigated the effects of bioactive molecules released from bone marrow and gestational tissue-derived hMSCs on the proliferation of various human cancer cells,including C3A,HT29,A549,Saos-2,and U251. We also characterized the hMSC-derived factors that inhibit cancer cell proliferation by protein fractionation and mass spectrometry analysis. Results We herein make a direct comparison and show that the effects of hMSCs on cancer cell proliferation and migration depend on both hMSC sources and cancer cell types and cancer-derived bioactive molecules did not affect the cancer suppressive capacity of hMSCs. Moreover,hMSCs use distinct combination of bioactive molecules to suppress the proliferation of human hepatoblastoma and colorectal cancer cells. Using protein fractionation and mass spectrometry analysis,we have identified several novel hMSC-derived factors that might be able to suppress cancer cell proliferation. Conclusion We believe that the procedure developed in this study could be used to discover other therapeutically useful molecules released by various hMSC sources for a future in vivo study. View Publication

NK cells are key innate immune cells that play critical roles in host defense. Although NK cells have been shown to regulate immunity to some infectious diseases,their role in immunity to Trypanosoma congolense has not been investigated. NK cells are vital sources of IFN-gamma and TNF-alpha; two key cytokines that are known to play important roles in resistance to African trypanosomes. In this article,we show that infection with T. congolense leads to increased levels of activated and functional NK cells in multiple tissue compartments. Systemic depletion of NK cells with anti-NK1.1 mAb led to increased parasitemia,which was accompanied by significant reduction in IFN-gamma production by immune cells in the spleens and liver of infected mice. Strikingly,infected NFIL3-/- mice (which genetically lack NK cell development and function) on the normally resistant background were highly susceptible to T. congolense infection. These mice developed fulminating and uncontrolled parasitemia and died significantly earlier (13 ± 1 d) than their wild-type control mice (106 ± 26 d). The enhanced susceptibility of NFIL3-/- mice to infection was accompanied by significantly impaired cytokine (IFN-gamma and TNF-alpha) response by CD3+ T cells in the spleens and liver. Adoptive transfer of NK cells into NFIL3-/- mice before infection rescued them from acute death in a perforin-dependent manner. Collectively,these studies show that NK cells are critical for optimal resistance to T. congolense,and its deficiency leads to enhanced susceptibility in infected mice. View Publication