After almost 30 years of promise tempered by setbacks, gene therapies are rapidly becoming a critical component of the therapeutic armamentarium for a variety of inherited and acquired human diseases. Gene therapies for inherited immune disorders, hemophilia, eye and neurodegenerative disorders, and lymphoid cancers recently progressed to approved drug status in the United States and Europe, or are anticipated to receive approval in the near future. In this Review, we discuss milestones in the development of gene therapies, focusing on direct in vivo administration of viral vectors and adoptive transfer of genetically engineered T cells or hematopoietic stem cells. We also discuss emerging genome editing technologies that should further advance the scope and efficacy of gene therapy approaches.

The molecular mechanisms by which mesenchymal stem cells (MSCs) suppress T-cell proliferation are poorly understood, and whether a soluble factor plays a major role remains controversial. Here we demonstrate that the T-cell-receptor complex is not a target for the suppression, suggesting that downstream signals mediate the suppression. We found that Stat5 phosphorylation in T cells is suppressed in the presence of MSCs and that nitric oxide (NO) is involved in the suppression of Stat5 phosphorylation and T-cell proliferation. The induction of inducible NO synthase (NOS) was readily detected in MSCs but not T cells, and a specific inhibitor of NOS reversed the suppression of Stat5 phosphorylation and T-cell proliferation. This production of NO in the presence of MSCs was mediated by CD4 or CD8 T cells but not by CD19 B cells. Furthermore, inhibitors of prostaglandin synthase or NOS restored the proliferation of T cells, whereas an inhibitor of indoleamine 2,3-dioxygenase and a transforming growth factor-␤-neutralizing antibody had no effect. Finally, MSCs from inducible NOS ؊/؊ mice had a reduced ability to suppress T-cell proliferation. Taken IntroductionBecause mesenchymal stem cells (MSCs) differentiate into osteocytes, chondrocytes, myotubes, and adipocytes, 1-3 they are expected to become a source of cells for regenerative therapy. Also, MSCs support hematopoietic stem cell engraftment 4-9 and modulate immunologic responses by unknown mechanisms. [9][10][11][12][13][14] Here, we investigated the molecular mechanisms by which MSCs suppress T-cell proliferation.Transforming growth factor-␤ (TGF-␤), hepatocyte growth factor, indoleamine 2,3-dioxygenase (IDO), and prostaglandin E2 (PGE 2 ) have been reported to mediate T-cell suppression by MSCs. [13][14][15] Specifically, neutralizing antibodies against TGF-␤ or hepatocyte growth factor, 13 an inhibitor of IDO,14 or an inhibitor of prostaglandin production reverse the inhibition of T-cell proliferation by MSCs. 15 In addition, some reports have shown that a soluble factor is the major mediator of suppression, [13][14][15][16][17] whereas some reports have demonstrated that T-cell-MSC contact is required for this suppression. [12][13][14]16,17 In the current study, we sought to resolve these conflicting results by using a mouse bone marrow-derived MSC system.One candidate soluble factor for T-cell suppression is nitric oxide (NO) because it is known to inhibit T-cell proliferation. [18][19][20][21][22][23][24][25] NO is produced by NO synthases (NOSs), of which there are 3 subtypes: inducible NOS (iNOS), endothelial NOS, and neuronal NOS. Like MSCs, it has been known that macrophages suppress T-cell proliferation. This suppression was reported to be mediated by NO inhibition of Stat5 phosphorylation. 18,19 Also, MSCs were reported to produce NO when they differentiate into chondrocytes. 26 We therefore investigated whether MSCs can produce NO and whether NO is involved in their ability to suppress T-cell proliferation. Materials and methods MaterialsN-nitro-L-a...

Acquired uniparental disomy (aUPD) is a common feature of cancer genomes, leading to loss of heterozygosity. aUPD is associated not only with loss-of-function mutations of tumour suppressor genes, but also with gain-of-function mutations of proto-oncogenes. Here we show unique gain-of-function mutations of the C-CBL (also known as CBL) tumour suppressor that are tightly associated with aUPD of the 11q arm in myeloid neoplasms showing myeloproliferative features. The C-CBL proto-oncogene, a cellular homologue of v-Cbl, encodes an E3 ubiquitin ligase and negatively regulates signal transduction of tyrosine kinases. Homozygous C-CBL mutations were found in most 11q-aUPD-positive myeloid malignancies. Although the C-CBL mutations were oncogenic in NIH3T3 cells, c-Cbl was shown to functionally and genetically act as a tumour suppressor. C-CBL mutants did not have E3 ubiquitin ligase activity, but inhibited that of wild-type C-CBL and CBL-B (also known as CBLB), leading to prolonged activation of tyrosine kinases after cytokine stimulation. c-Cbl(-/-) haematopoietic stem/progenitor cells (HSPCs) showed enhanced sensitivity to a variety of cytokines compared to c-Cbl(+/+) HSPCs, and transduction of C-CBL mutants into c-Cbl(-/-) HSPCs further augmented their sensitivities to a broader spectrum of cytokines, including stem-cell factor (SCF, also known as KITLG), thrombopoietin (TPO, also known as THPO), IL3 and FLT3 ligand (FLT3LG), indicating the presence of a gain-of-function that could not be attributed to a simple loss-of-function. The gain-of-function effects of C-CBL mutants on cytokine sensitivity of HSPCs largely disappeared in a c-Cbl(+/+) background or by co-transduction of wild-type C-CBL, which suggests the pathogenic importance of loss of wild-type C-CBL alleles found in most cases of C-CBL-mutated myeloid neoplasms. Our findings provide a new insight into a role of gain-of-function mutations of a tumour suppressor associated with aUPD in the pathogenesis of some myeloid cancer subsets.

p130Cas is a major tyrosine-phosphorylated protein that tightly binds v-Crk in v-crk-transformed cells and v-Src in v-src-transformed cells. The "substrate domain" of p130Cas contains 15 possible Src homology (SH) 2-binding motifs, most of which conform to the binding motif for the Crk SH2 domain. Another region near its C terminus contains possible binding motifs for the Src SH2 domain and proline-rich sequences that are candidates for SH3-binding sites.Using GST fusion proteins, we revealed that both SH2 and SH3 domains of Src bind p130

Here we investigated the transduction characteristics of adeno-associated viral vector (AAV) serotypes 1, 2, 5, 8 and 9 in the marmoset cerebral cortex. Using three constructs that each has hrGFP under ubiquitous (CMV), or neuron-specific (CaMKII and Synapsin I (SynI)) promoters, we investigated (1) the extent of viral spread, (2) cell type tropism, and (3) neuronal transduction efficiency of each serotype. AAV2 was clearly distinct from other serotypes in small spreading and neuronal tropism. We did not observe significant differences in viral spread among other serotypes. Regarding the cell tropism, AAV1, 5, 8 and 9 exhibited mostly glial expression for CMV construct. However, when the CaMKII construct was tested, cortical neurons were efficiently transduced (>∼70% in layer 3) by all serotypes, suggesting that glial expression obscured neuronal expression for CMV construct. For both SynI and CaMKII constructs, we observed generally high-level expression in large pyramidal cells especially in layer 5, as well as in parvalbumin-positive interneurons. The expression from the CaMKII construct was more uniformly observed in excitatory cells compared with SynI construct. Injection of the same viral preparations in mouse and macaque cortex resulted in essentially the same result with some species-specific differences.