Enhanced effect of microdystrophin gene transfection by HSV-VP22 mediated intercellular protein transport

VP22 herpes simplex virus protein can transduce proteins into stem cells

The type I herpes simplex virus VP22 tegument protein is abundant and well known for its ability to translocate proteins from one cell to the other. In spite of some reports questioning its ability to translocate proteins by attributing the results observed to fixation artifacts or simple attachment to the cell membrane, VP22 has been used to deliver several proteins into different cell types, triggering the expected cell response. However, the question of the ability of VP22 to enter stem cells has not been addressed. We investigated whether VP22 could be used as a tool to be applied in stem cell research and differentiation due to its capacity to internalize other proteins without altering the cell genome. We generated a VP22.eGFP construct to evaluate whether VP22 could be internalized and carry another protein with it into two different types of stem cells, namely adult human dental pulp stem cells and mouse embryonic stem cells. We generated a VP22.eGFP fusion protein and demonstrated that, in fact, it enters stem cells. Therefore, this system may be used as a tool to deliver various proteins into stem cells, allowing stem cell research, differentiation and the generation of induced pluripotent stem cells in the absence of genome alterations.

Transgene expression and differentiation of baculovirus-transduced adipose-derived stem cells from dystrophin-utrophin double knock-out mouse

In this study, recombinant baculovirus carrying the microdystrophin and β-catenin genes was used to infect adipose-derived stem cells from a dystrophin-utrophin double knock-out mouse. Results showed that, after baculovirus transgene infection, microdystrophin and β-catenin genes were effectively expressed in adipose-derived stem cells from the dystrophin-utrophin double knock-out mouse. Furthermore, this transgenic expression promoted adipose-derived stem cell differentiation into muscle cells, but inhibited adipogenic differentiation. In addition, protein expression related to the microdystrophin and Wnt/β-catenin signaling pathway was upregulated. Our experimental findings indicate that baculovirus can successfully deliver the microdystrophin and β-catenin genes into adipose-derived stem cells, and the microdystrophin and Wnt/β-catenin signaling pathway plays an important role in myogenesis of adipose-derived stem cells in the dystrophin-utrophin double knock-out mouse.

Cellular mechanism underlying the facilitation of contractile response of vas deferens smooth muscle by sodium orthovanadate

In the earlier study, sodium orthovanadate (SOV) has been reported to be a powerful inhibitor of (Na(+), K(+)) adenosine triphosphatase, exhibit widespread actions on the renal and cardiovascular systems, induces smooth muscle contraction by inhibiting the phosphorylation of the protein tyrosine phosphatases. In the current study, we aimed to investigate the cellular mechanisms by which SOV facilitated contractile response of vas deferens smooth muscle and its potential therapeutic advantage. Exogenous application of ATP and NA-caused contraction was strengthened by pretreatment with SOV. This facilitation was inhibited not by bath with the inhibitor of P2 receptor, PPADS, or the inhibitor of α1 receptor, Prazosin, but by bath with the protein tyrosine kinase inhibitor, Genistein. SOV induced a sustained increase in intracellular Ca(2+) of smooth muscle cells, which was abolished by 100 μM Genistein or Ca(2+)-free solution. The facilitation of SOV could also be inhibited by the selective inhibitors of TRP channel, 2-APB and non-selective cation channel, Gd(3+), Ni(+). The in vivo study showed that peritoneal injection of SOV in dystrophic mice (mdx mice) enhanced the contraction of vas deferens smooth muscle stimulated by electrical field stimulation, ATP, noradrenaline, or KCl. The above results suggest that SOV facilitates the concentration of vas deferens smooth muscle through the tyrosine phosphorylation activated the non-selective cation channels, which has potential use in the therapy for muscle dysfunction.

Electrotransfer of the full-length dog dystrophin into mouse and dystrophic dog muscles

Duchenne muscular dystrophy (DMD) is an X-linked genetic disease characterized by the absence of dystrophin (427 kDa). An approach to eventually restore this protein in patients with DMD is to introduce into their muscles a plasmid encoding dystrophin cDNA. Because the phenotype of the dystrophic dog is closer to the human phenotype than is the mdx mouse phenotype, we have studied the electrotransfer of a plasmid carrying the full-length dog dystrophin (FLDYS(dog)) in dystrophic dog muscle. To achieve this nonviral delivery, the FLDYS(dog) cDNA was cloned in two plasmids containing either a cytomegalovirus or a muscle creatine kinase promoter. In both cases, our results showed that the electrotransfer of these large plasmids (∼17 kb) into mouse muscle allowed FLDYS(dog) expression in the treated muscle. The electrotransfer of pCMV.FLDYS(dog) in a dystrophic dog muscle also led to the expression of dystrophin. In conclusion, introduction of the full-length dog dystrophin cDNA by electrotransfer into dystrophic dog muscle is a potential approach to restore dystrophin in patients with DMD. However, the electrotransfer procedure should be improved before applying it to humans.

Microdystrophin delivery in dystrophin-deficient (mdx) mice by genetically-corrected syngeneic MSCs transplantation

Cell transplantation and gene therapy are two promising therapeutical approaches for the treatment on Duchenne Muscular Dystrophy (DMD). However, both strategies have met many hurdles, mainly because of the absence of an efficient systemic delivery system on gene therapy and immune reactionns on cell transplantation. In this project, we investigated the strategy based on combination of these two basic ones, ie, transplantation of transgene-corrected mdx mesenchymal stem cells (MSCs) into mdx mice to cure DMD. The MSCs isolated from male mdx mice were transduced with recombinant adenovirus including human microdystrophin gene and labeled with BrdU were transplanted into female mdx mice, the Chimerism with the sex-determinant Y chromosome and human microdystrophin expression were detected. Simultaneously, the plasma creatine kinase (CK) activity, the improvement with the muscles' pathology and contractile propertie were evaluated. The results clearly demonstrated that some human dystrophin and BrdU expression collectively were detected in some muscles of transplanted mdx mice. Moreover, the CK activity and percentage of centrally nucleated fiber (CNF) decreased slightly after transplanation. Regrettably, the protective effect on contraction-induced injury in TA and diaphragm muscles wasn't significantly improvement after transplantation. Our results suggested, if enhancement on the efficiency with cell transplantation, that the transplantation of autologous MSCs corrected by dystrophin may be a form to treat DMD patients in future.

Endotoxin deactivation by transient acidification

Recombinant proteins are an important tool for research and therapeutic applications. Therapeutic proteins have been delivered to several cell types and tissues and might be used to improve the outcome of the cell transplantation. Recombinant proteins are propagated in bacteria, which will contaminate them with the lypopolysacharide endotoxin found in the outer bacterial membrane. Endotoxin could interfere with in vitro biological assays and is the major pathological factor, which must be removed or inactivated before in vivo administration. Here we describe a one-step protocol in which the endotoxin activity on recombinant proteins is remarkably reduced by transient exposure to acidic conditions. Maximum endotoxin deactivation occurs at acidic pH below their respective isoelectric point (pI). This method does not require additional protein purification or separation of the protein from the endotoxin fraction. The endotoxin level was measured both in vitro and in vivo. For in vitro assessment we have utilized Limulus Amebocyte Lysate method for in vivo the pyrogenic test. We have tested the above-mentioned method with five different recombinant proteins, including a monoclonal antibody clone 5c8 against CD154 produced by hybridomas. More than 99% of endotoxin was deactivated in all of the proteins; the recovery of the protein after deactivation varied between maximum 72.9% and minimum 46.8%. The anti-CD154 clone 5c8 activity remained unchanged as verified by the measurement of binding capability to activated lymphocytes. Furthermore, the effectiveness of this method was not significantly altered by urea, commonly used in protein purification. This procedure provides a simple and cost-efficient way to reduce the endotoxin activity in antibodies and recombinant proteins.

Therapeutic approaches for the sarcomeric protein diseases

No curative treatment currently exists for patients with skeletal myopathies caused by defects in sarcomeric proteins though symptomatic treatments including orthoses, night-time ventilation, or mechanical ventilation can provide major benefits. The molecular genetic discovery era has enabled many families to know which gene and precisely which gene defect their family, or in some cases only their affected child has. This knowledge has enormously increased the accuracy of genetic counselling and in some cases can enable prognosis, which helps families to make better-informed life decisions. However, symptomatic treatments and molecular genetics do not help the patient's skeletal muscle problems. The patients with skeletal muscle sarcomeric protein diseases, (from severely affected patients with shortened lifespan, through to the more mildly affected patients), would all benefit from more effective or curative treatments, as would their parents and families. This chapter outlines the experimental therapeutic strategies that have been investigated for other muscle diseases (predominantly the muscular dystrophies, towards which the majority of research emphasis has been focussed) and those that are beginning to be investigated for sarcomeric diseases. It analyses which of these approaches might be applicable to the different skeletal muscle sarcomeric protein diseases.