Mesenchymal stem cells (MSC) were reported to ameliorate functional deficits after stroke in rats, with some of this improvement possibly resulting from the action of cytokines secreted by these cells. To enhance such cytokine effects, we previously transfected the telomerized human MSC with the BDNF gene using a fiber-mutant adenovirus vector and reported that such treatment contributed to improved ischemic recovery in a rat transient middle cerebral artery occlusion (MCAO) model. In the present study, we investigated whether other cytokines in addition to BDNF, i.e., GDNF, CNTF, or NT3, might have a similar or greater effect in this model. Rats that received MSC-BDNF (P < 0.05) or MSC-GDNF (P < 0.05) showed significantly more functional recovery as demonstrated by improved behavioral test results and reduced ischemic damage on MRI than did control rats 7 and 14 days following MCAO. On the other hand, rats that received MSC-CNTF or MSC-NT3 showed neither functional recovery nor ischemic damage reduction compared to control rats. Thus, MSC transfected with the BDNF or GDNF gene resulted in improved function and reduced ischemic damage in a rat model of MCAO. These data suggest that gene-modified cell therapy may be a useful approach for the treatment of stroke.

Examination of the clinical therapeutic efficacy of using bone marrow stromal cells, including mesenchymal stem cells (MSC), has recently been the focus of much investigation. MSC were reported to ameliorate functional deficits after stroke in rats, with some of this improvement possibly resulting from the action of cytokines secreted by these cells. To enhance such cytokine effects, we transfected telomerized human MSC with the BDNF gene using a fiber-mutant F/RGD adenovirus vector and investigated whether these cells contributed to improved functional recovery in a rat transient middle cerebral artery occlusion (MCAO) model. BDNF production by MSC-BDNF cells was 23-fold greater than that seen in uninfected MSC. Rats that received MSC-BDNF showed significantly more functional recovery than did control rats following MCAO. Specifically, MRI analysis revealed that the rats in the MSC-BDNF group exhibited more significant recovery from ischemia after 7 and 14 days. The number of TUNEL-positive cells in the ischemic boundary zone was significantly smaller in animals treated with MSC-BDNF compared to animals in the control group. These data suggest that MSC transfected with the BDNF gene may be useful in the treatment of cerebral ischemia and may represent a new strategy for the treatment of stroke.

Historic Prussian blue (PB) pigment is easily obtained as an insoluble precipitate in quantitative yield from an aqueous mixture of Fe 3+ and [Fe II (CN) 6 ] 4− (Fe 2+ and [Fe III (CN) 6 ] 3−). It has been found that the PB pigment is inherently an agglomerate of 10-20 nm nanoparticles, based on powder x-ray diffraction (XRD) line broadenings and transmission electron microscopy (TEM) images. The PB pigment has been revived as both organic-solvent-soluble and water-soluble nanoparticle inks. Through crystal surface modification with aliphatic amines, the nanoparticles are stably dispersed from the insoluble agglomerate into usual organic solvents to afford a transparent blue solution. Identical modification with [Fe(CN) 6 ] 4− yields water-soluble PB nanoparticles. A similar ink preparation is applicable to Ni-PBA and Co-PBA (nickel and cobalt hexacyanoferrates). The PB (blue), Ni-PBA (yellow), and Co-PBA (red) nanoparticles function as three primary colour inks.

Glioblastoma multiforme (GBM) remains an untreatable human brain malignancy. Despite promising preclinical studies using oncolytic herpes simplex virus (oHSV) vectors, efficacy in patients has been limited by inefficient virus replication in tumor cells. This disappointing outcome can be attributed in part to attenuating mutations engineered into these viruses to prevent replication in normal cells. Alternatively, retargeting of fully replication-competent HSV to tumor-associated receptors has the potential to achieve tumor specificity without impairment of oncolytic activity. Here, we report the establishment of an HSV retargeting system that relies on the combination of two engineered viral glycoproteins, gD and gB, to mediate highly efficient HSV infection exclusively through recognition of the abundantly expressed epidermal growth factor receptor (EGFR) on glioblastoma cells. We demonstrate efficacy in vitro and in a heterotopic tumor model in mice. Evidence for systemically administered virus homing to the tumor mass is presented. Treatment of orthotopic primary human GBM xenografts demonstrated prolonged survival with up to 73% of animals showing a complete response as confirmed by magnetic resonance imaging. Our study describes an approach to HSV retargeting that is effective in a glioma model and may be applicable to the treatment of a broad range of tumor types.

Gene targeting using short interfering RNA (siRNA) has become a common strategy to explore gene function because of its prominent efficacy and specificity. For the application of siRNA technology to gene therapy, however, still more efficient transduction of siRNA into target cells is needed. In this study, we developed an adenoviral vector harboring a tandem-type siRNA expression unit, in which sense and antisense strands composing the siRNA duplex were separately transcribed by two human U6 promoters. Targeting survivin, an antiapoptotic molecule widely overexpressed in malignancies but not detected in terminally differentiated adult tissues, this type of adenoviral vector (Adv-siSurv) successfully exerted a gene knockdown effect and induced apoptosis in HeLa, U251, and MCF-7 cells. These cancer cells, once infected with Adv-siSurv, displayed remarkably attenuated growth potential, both in vitro and in vivo. Moreover, intratumoral injection of Adv-siSurv significantly suppressed tumor growth in a xenograft model using U251 glioma cells. This novel modality may be a promising tool for cancer therapy.

The design of highly defective herpes simplex virus (HSV) vectors for transgene expression in nonneuronal cells in the absence of toxic viral-gene activity has been elusive. Here, we report that elements of the latency locus protect a nonviral promoter against silencing in primary human cells in the absence of any viral-gene expression. We identified a CTCF motif cluster 5′ to the latency promoter and a known long-term regulatory region as important elements for vigorous transgene expression from a vector that is functionally deleted for all five immediate-early genes and the 15-kb internal repeat region. We inserted a 16.5-kb expression cassette for full-length mouse dystrophin and report robust and durable expression in dystrophin-deficient muscle cells in vitro. Given the broad cell tropism of HSV, our design provides a nontoxic vector that can accommodate large transgene constructs for transduction of a wide variety of cells without vector integration, thereby filling an important void in the current arsenal of gene-therapy vectors.

Strategies using mesenchymal stem cell (MSC)-mediated gene therapy have been developed to improve bone healing. However, transduction efficiency into MSCs by each vector is not always high. To overcome this problem, we used a modified adenoviral vector (Adv-F/RGD) with an RGD-containing peptide in the HI loop of the fiber knob domain of adenovirus type 5 (Ad5). Transduction efficiency into bone marrow-derived MSCs with Adv-F/RGD increased 12-fold compared with a vector containing the wild-type fiber (Adv-F/wt) by beta-galactosidase chemiluminescent assay. As a next step, we constructed AxCAhBMP2-F/RGD and AxCAhBMP2-F/wt carrying human bone morphogenetic protein 2 (BMP2). At the same multiplicity of infection, MSCs infected with AxCAhBMP2-F/RGD produced higher amounts of BMP2 than cells infected with AxCAhBMP2-F/wt, and also differentiated towards the osteogenic lineage more efficiently in vitro. Furthermore, using ex vivo gene transduction, we evaluated the potential for ectopic bone formation by the transduced MSCs in vivo. Transduction with AxCAhBMP2-F/RGD exhibited greatly enhanced new bone formation. These data suggest that Adv-F/RGD is useful for introducing foreign genes into MSCs and that it will be a powerful gene therapy tool for bone regeneration and other tissue engineering.

Glioblastoma multiforme (GBM) is an aggressive brain cancer for which there is no effective treatment. Oncolytic HSV vectors (oHSVs) are attenuated lytic viruses that have shown promise in the treatment of human GBM models in animals, but their efficacy in early phase patient trials has been limited. Instead of attenuating the virus with mutations in virulence genes, we engineered four copies of the recognition sequence for miR-124 into the 3'UTR of the essential ICP4 gene to protect healthy tissue against lytic virus replication; miR-124 is expressed in neurons but not in glioblastoma cells. Following intracranial inoculation into nude mice, the miR-124-sensitive vector failed to replicate or show overt signs of pathogenesis. To address the concern that this safety feature may reduce oncolytic activity, we inserted the miR-124 response elements into an unattenuated, human receptor (EGFR/EGFRvIII)-specific HSV vector. We found that miR-124 sensitivity did not cause a loss of treatment efficiency in an orthotopic model of primary human GBM in nude mice. These results demonstrate that engineered miR-124 responsiveness can eliminate off-target replication by unattenuated oHSV without compromising oncolytic activity, thereby providing increased safety.