High-efficiency electrotransfection of human primary hematopoietic stem cells

Comparative Efficiency for in vitro Transfection of Goat Undifferentiated Spermatogonia Using Lipofectamine Reagents and Electroporation

Introduction

Spermatogonial stem cells (SSC), also referred to as undifferentiated spermatogonia, are the germline stem cells responsible for continuous spermatogenesis throughout a male’s life. They are, therefore, an ideal target for gene editing. Previously, SSC from animal testis have been isolated and transplanted to homologous recipients resulting in the successful reestablishment of donor-derived spermatogenesis.

Methods

Enhanced green fluorescent protein (eGFP) gene transfection into goat SSC was evaluated using liposomal carriers and electroporation. The cells were isolated from the prepubertal Galla goats testis cultured in serum-free defined media and transfected with the eGFP gene. Green fluorescing of SSC colonies indicated transfection.

Results

The use of lipofectamine^TM stem reagent and lipofectamine^TM 2000 carriers resulted in more SSC colonies expressing the eGFP gene (25.25% and 22.25%, respectively). Electroporation resulted in 15% ± 0.54 eGFP expressing SSC colonies. Furthermore, cell viability was higher in lipofectamine transfection (55% ± 0.21) as compared to electroporation (38% ± 0.14).

Conclusion

These results indicated that lipofectamine was more effective in eGFP gene transfer into SSC. The successful transient transfection points to a possibility of transfecting transgenes into male germ cells in genetic engineering programs.

A statistical framework for determination of minimal plasmid copy number required for transgene expression in mammalian cells

Plasmid DNA (pDNA) has been widely used for non-viral gene delivery. After pDNA molecules enter a mammalian cell, they may be trapped in subcellular structures or degraded by nucleases. Only a fraction of them can function as templates for transcription in the nucleus. Thus, an important question is, what is the minimal amount of pDNA molecules that need to be delivered into a cell for transgene expression? At present, it is technically a challenge to experimentally answer the question. To this end, we developed a statistical framework to establish the relationship between two experimentally quantifiable factors - average copy number of pDNA per cell among a group of cells after transfection and percent of the cells with transgene expression. The framework was applied to the analysis of electrotransfection under different experimental conditions in vitro. We experimentally varied the average copy number per cell and the electrotransfection efficiency through changes in extracellular pDNA dose, electric field strength, and pulse number. The experimental data could be explained or predicted quantitatively by the statistical framework. Based on the data and the framework, we could predict that the minimal number of pDNA molecules in the nucleus for transgene expression was on the order of 10. Although the prediction was dependent on the cell and experimental conditions used in the study, the framework may be generally applied to analysis of non-viral gene delivery.

Delivery of RNA-based molecules to human hematopoietic stem and progenitor cells for modulation of gene expression

Gene modulation of human hematopoietic stem and progenitor cells (HSPCs) harbors great potential for therapeutic application of these cells and presents a versatile tool in basic research to enhance our understanding of HSPC biology. However, stable genetic modification might be adverse, particularly in clinical settings. Here, we review a broad range of approaches to transient, nonviral modulation of protein expression with a focus on RNA-based methods. We compare different delivery methods and describe the usefulness of RNA molecules for overexpression as well as downregulation of proteins in HSPCs.

Comparison of Different Electroporation Parameters on Transfection Efficiency of Sheep Testicular Cells

OBJECTIVE

Electroporation can be a highly efficient method for introducing the foreign genetic materials into the targeted cells for transient and/or permanent genetic modification. Considering the application of this technique as a very efficient method for drug, oligonucleotide, antibody and plasmid delivery for clinical applications and production of transgenic animals, the present study aimed to optimize the transfection efficiency of sheep testicular cells including spermatogonial stem cells (SSCs) via electroporation.

MATERIALS AND METHODS

This study is an experimental research conducted in Biotechnology Research Center (Avicenna Research Institute, Tehran, Iran) from September 2013 to March 2014. Following isolation and propagation of one-month lamb testicular cells (SSCs and somatic testicular cells including; Sertoli, Leydig, and myoid cells), the effect of different electroporation parameters including total voltages (280, 320, and 350 V), burst durations (10, 8, and 5 milliseconds), burst modes (single or double) and addition of dimethyl sulfoxide (DMSO) were evaluated on transfection efficiency, viability rate and mean fluorescent intensity (MFI) of sheep testicular cells.

RESULTS

The most transfection efficiency was obtained in 320 V/8 milliseconds/single burst group in transduction medium with and without DMSO. There was a significantly inverse correlation between transfection efficiency with application of both following parameters: addition of DMSO and double burst. After transfection, the highest and lowest viability rates of testicular cells were demonstrated in 320 V/8 milliseconds with transduction medium without DMSO and 350 V/5 milliseconds in medium containing DMSO. Ad- dition of DMSO to transduction medium in all groups significantly decreased the viability rate. The comparison of gene expression indicated that Sertoli and SSCs had the most fluorescence intensity in 320 V/double burst/DMSO positive. However, myoid and Leydig cells showed the maximum expression in 320 V/single burst and/or 350 V/double burst/ DMSO positive.

CONCLUSION

We optimized the electroporation method for transfection of sheep testicular cells and recommended the application of 320 V/8 milliseconds/single pulse/DMSO negative for transduction of plasmid vector into these cells. Among testicular cells, the most external gene expression was demonstrated in SSC population.

Large volume flow electroporation of mRNA: clinical scale process

Genetic modification for enhancing cellular function has been continuously pursued for fighting diseases. Messenger RNA (mRNA) transfection is found to be a promising solution in modifying hematopoietic and immune cells for therapeutic purpose. We have developed a flow electroporation-based system for large volume electroporation of cells with various molecules, including mRNA. This allows robust and scalable mRNA transfection of primary cells of different origin. Here we describe transfection of chimeric antigen receptor (CAR) mRNA into NK cells to modulate the ability of NK cells to target tumor cells. High levels of CAR expression in NK cells can be maintained for 3-7 days post transfection. CD19-specific CAR mRNA transfected NK cells demonstrate targeted lysis of CD19-expressing tumor cells OP-1, primary B-CLL tumor cells, and autologous CD19+ B cells in in vitro assays with enhanced potency: >80% lysis at effector-target ratio of 1:1. This allows current good manufacturing practices (cGMP) and regulatory compliant manufacture of CAR mRNA transfected NK cells for clinical delivery.

Evidence of interlinks between bioelectromagnetics and biomechanics: from biophysics to medical physics

A vast literature on electromagnetic and mechanical bioeffects at the bone and soft tissue level, as well as at the cellular level (osteoblasts, osteoclasts, keratinocytes, fibroblasts, chondrocytes, nerve cells, endothelial and muscle cells) has been reviewed and analysed in order to show the evident connections between both types of physical energies. Moreover, an intimate link between the two is suggested by transduction phenomena (electromagnetic-acoustic transduction and its reverse) occurring in living matter, as a sound biophysical literature has demonstrated. However, electromagnetic and mechanical signals are not always interchangeable, depending on their respective intensity. Calculations are reported in order to show in which cases (read: for which values of electric field in V/m and of mechanical pressure in Pa) a given electromagnetic or mechanical bioeffect is only due to the directly impinging energy or even to the indirect transductional energy. The relevance of the treated item for the applications of medical physics to regenerative medicine is stressed.

¹⁹F MRI tracer preserves in vitro and in vivo properties of hematopoietic stem cells

Hematopoietic stem cells (HSCs) have numerous therapeutic applications including immune reconstitution, enzyme replacement, regenerative medicine, and immunomodulation. The trafficking and persistence of these cells after administration is a fundamental question for future therapeutic applications of HSCs. Here, we describe the safe and efficacious labeling of human CD34(+) HSCs with a novel, self-delivering perfluorocarbon ¹⁹F magnetic resonance imaging (MRI) tracer, which has recently been authorized for use in a clinical trial to track therapeutic cells. While various imaging contrast agents have been used to track cellular therapeutics, the impact of this MRI tracer on HSC function has not previously been studied. Both human CD34(+) and murine bone marrow (BM) HSCs were effectively labeled with the MRI tracer, with only a slight reduction in viability, relative to mock-labeled cells. In a pilot study, ¹⁹F MRI enabled the rapid evaluation of HSC delivery/retention following administration into a rat thigh muscle, revealing the dispersal of HSCs after injection, but not after surgical implantation. To investigate effects on cell functionality, labeled and unlabeled human HSCs were tested in in vitro colony forming unit (CFU) assays, which resulted in equal numbers of total CFU as well as individual CFU types, indicating that labeling did not alter multipotency. Cobblestone assay forming cell precursor frequency was also unaffected, providing additional evidence that stem cell function was preserved after labeling. In vivo tests of multipotency and reconstitution studies in mice with murine BM containing labeled HSCs resulted in normal development of CFU in the spleen, compared to unlabeled cells, and reconstitution of both lymphoid and myeloid compartments. The lack of interference in these complex biological processes provides strong evidence that the function and therapeutic potential of the HSCs are likely maintained after labeling. These data support the safety and efficacy of the MRI tracer for clinical tracking of human stem cells.

Cationic liposome-mediated CXCR4 gene delivery into hematopoietic stem/progenitor cells: implications for clinical transplantation and gene therapy

The chemokine stromal cell-derived factor (SDF)-1α/CXCL12 and its receptor CXC chemokine receptor 4 (CXCR4) play a crucial role in the homing/engraftment and retention of hematopoietic stem/progenitor cells (HSPCs) in the bone marrow. It has been shown using the viral gene transfer technique that CXCR4 overexpression on human CD34(+) HSPC significantly improves their engraftment in murine models. However, clinical trials with gene therapy have revealed safety concerns related to the immunogenicity of the viral carriers, due to the random integration of viral genes into the host genome. Therefore, a method for CXCR4 gene delivery into HSPC that is safe, nonviral, and highly efficient is needed to improve clinical transplantation and gene therapies. In this work, we investigated the nonviral CXCR4 gene delivery into HSPC using the cationic liposome agent IBAfect. We used CD34(+) cells from cord blood and the models of immature hematopoietic cells expressing CD34 antigen, namely, leukemic cell lines KG-1a and KG-1. Transfection efficiency was determined by flow cytometric analysis 12, 24, 48, and 72 h after transfection, and the viability of cells analyzed by trypan blue exclusion and MTS assays. The functional response of CXCR4-transfected HSPC toward an SDF-1α gradient was determined by chemotaxis assay. We found that ~25% transfection is achieved for KG-1a and KG-1 cells and 20% for HSPC, and that the viability of CXCR4-transfected HSPC is not significantly altered. More importantly, overexpression of CXCR4 using IBAfect significantly increased the chemotaxis of KG-1 cells and HSPC toward SDF-1α. However, we tested 2 other commercially available cationic liposomes (Lipofectamine 2000 and 1,2-dioleoyl-3-trimethylammonium-propane [DOTAP]) in parallel, and we found that they failed to deliver the CXCR4 gene into cells under the same conditions. These results suggest that IBAfect-mediated in vitro gene delivery to overexpress CXCR4 on HSPC is a safe and efficient technique with great potential for improving the efficacy of HSPC transplantation and gene therapy protocols.

Transient knock down of checkpoint kinase 1 in hematopoietic progenitors is linked to bone marrow toxicity

Checkpoint kinase 1 (Chk1) is required for both intra-S phase and G2/M checkpoints in cell cycle, and plays critical roles in maintaining genomic stability and transducing DNA damage response. Chk1 deficiency has been shown to inhibit T-cell differentiation and resulted in severe anemia in a Chk1 heterozygous mouse model. To date, there has been a good correlation between Chk1 inhibition and in vitro bone marrow toxicity among small molecule inhibitors. To better understand the role of Chk1 in hematopoiesis, we conducted transient Chk1 gene silencing in human bone marrow progenitor cells using siRNA and electroporation. At 48h post electroporation, approximately 70% inhibition of Chk1 was confirmed using real-time RT-PCR and immunoblotting, which resulted in more than 60% reduction in cell count when compared to the non-specific siRNA control on day 6 post-electroporation. This result was confirmed using a colony forming unit assay, where reduced number in both erythroid and granulocyte colonies was observed with Chk1 siRNA treatment. The Chk1 gene inhibition in bone marrow progenitor cells resulted in significant induction of apoptosis, but not cell cycle arrest, as assessed using flow cytometry. In this study an effective method to knock down a gene of interest was established in hard-to-transfect hematopoietic stem cells. Furthermore, our results support a direct role of Chk1 in maintaining normal hematopoiesis in the bone marrow.

Effect of chemokine receptor CXCR4 on hypoxia-induced pulmonary hypertension and vascular remodeling in rats

BACKGROUND

CXCR4 is the receptor for chemokine CXCL12 and reportedly plays an important role in systemic vascular repair and remodeling, but the role of CXCR4 in development of pulmonary hypertension and vascular remodeling has not been fully understood.

METHODS

In this study we investigated the role of CXCR4 in the development of pulmonary hypertension and vascular remodeling by using a CXCR4 inhibitor AMD3100 and by electroporation of CXCR4 shRNA into bone marrow cells and then transplantation of the bone marrow cells into rats.

RESULTS

We found that the CXCR4 inhibitor significantly decreased chronic hypoxia-induced pulmonary hypertension and vascular remodeling in rats and, most importantly, we found that the rats that were transplanted with the bone marrow cells electroporated with CXCR4 shRNA had significantly lower mean pulmonary pressure (mPAP), ratio of right ventricular weight to left ventricular plus septal weight (RV/(LV+S)) and wall thickness of pulmonary artery induced by chronic hypoxia as compared with control rats.

CONCLUSIONS

The hypothesis that CXCR4 is critical in hypoxic pulmonary hypertension in rats has been demonstrated. The present study not only has shown an inhibitory effect caused by systemic inhibition of CXCR4 activity on pulmonary hypertension, but more importantly also has revealed that specific inhibition of the CXCR4 in bone marrow cells can reduce pulmonary hypertension and vascular remodeling via decreasing bone marrow derived cell recruitment to the lung in hypoxia. This study suggests a novel therapeutic approach for pulmonary hypertension by inhibiting bone marrow derived cell recruitment.

Foe turned friend: multiple functional roles attributable to hyper-activating stem cell factor receptor mutant in regeneration of the haematopoietic cell compartment

OBJECTIVES

Stem cell factor receptor, c-kit, is considered to be the master signalling molecule of haematopoietic stem cells. It develops the orchestral pattern of haematopoietic cell lineages, seen by its varying degree of omnipresence in progenitors, lineage committed and mature cells. We have investigated the effect of over-expressing c-kit on early recovery of the haematopoietic compartment, in irradiated hosts.

MATERIALS AND METHODS

Normal bone marrow cells (BMCs) were transfected with Kit(wt) (wild-type c-kit) or its variant Kit(mu) (asp814tyr) by electroporation. Lethally irradiated mice were transplanted with normal or transfected congeneic BMCs. The effect of ectopic expression of c-kit on haematopoietic cell recovery was determined by analysing donor-derived cells. Furthermore, effects of both types of c-kit over-expression on progenitor and lineage-committed cells were examined by flow cytometric analysis of Sca-1 and lineage-committed (Lin(+)) cells respectively.

RESULTS

Hyper-activating Kit(mu) significantly improved recovery of the haematopoietic system in irradiated hosts. In vivo results showed that the donor-derived c-kit(+) cell population was increased to more than 3-fold in the case of Kit(mu)-transfected cells compared to normal and Kit(wt) over-expressing BMCs. In general, survival of progenitor and committed cell was improved in the Kit(mu) over-expressing system compared to the other two cohorts.

CONCLUSION

These results suggest that recruitment of the hyper-activating variant of c-kit (Kit(mu)) lead to early recovery of the bone marrow of lethally irradiated mice.

Expression of chimeric antigen receptors in natural killer cells with a regulatory-compliant non-viral method

Natural killer (NK) cells hold promise for cancer therapy. NK cytotoxicity can be enhanced by expression of chimeric antigen receptors that re-direct specificity toward target cells by engaging cell surface molecules expressed on target cells. We developed a regulatory-compliant, scalable non-viral approach to engineer NK cells to be target-specific based on transfection of mRNA encoding chimeric receptors. Transfection of eGFP mRNA into ex vivo expanded NK cells (N=5) or purified unstimulated NK cells from peripheral blood (N=4) resulted in good cell viability with eGFP expression in 85+/-6% and 86+/-4%, 24 h after transfection, respectively. An mRNA encoding a receptor directed against CD19 (anti-CD19-BB-z) was also transfected into NK cells efficiently. Ex vivo expanded and purified unstimulated NK cells expressing anti-CD19-BB-z exhibited enhanced cytotoxicity against CD19(+) target cells resulting in > or =80% lysis of acute lymphoblastic leukemia and B-lineage chronic lymphocytic leukemia cells at effector target ratios lower than 10:1. The target-specific cytotoxicity for anti-CD19-BB-z mRNA-transfected NK cells was observed as early as 3 h after transfection and persisted for up to 3 days. The method described here should facilitate the clinical development of NK-based antigen-targeted immunotherapy for cancer.

Electroporation as an efficient physical enhancer for skin drug delivery

Transdermal drug delivery offers an attractive alternative to the conventional drug delivery methods of oral administration and injection. However, the stratum corneum acts as a barrier that limits the penetration of substances through the skin. Application of high-voltage pulses to the skin increases its permeability (electroporation) and enables the delivery of various substances into and through the skin. The application of electroporation to the skin has been shown to increase transdermal drug delivery. Moreover, electroporation, used alone or in combination with other enhancement methods, expands the range of drugs (small to macromolecules, lipophilic or hydrophilic, charged or neutral molecules) that can be delivered transdermally. The efficacy of transport depends on the electrical parameters and the physicochemical properties of drugs. The in vivo application of high-voltage pulses is well tolerated, but muscle contractions are usually induced. The electrode and patch design is an important issue to reduce the discomfort of the electrical treatment in humans. This review presents the main findings in the field of electroporation-namely, transdermal drug delivery. Particular attention is paid to proposed enhancement mechanisms and trends in the field of topical and transdermal delivery.

Efficient siRNA delivery by the cationic liposome DOTAP in human hematopoietic stem cells differentiating into dendritic cells

RNA interference technology is an ideal strategy to elucidate the mechanisms associated with human CD34(+) hematopoietic stem cell differentiation into dendritic cells. Simple manipulations in vitro can unequivocally yield alloreactive or tolerogenic populations, suggesting key implications of biochemical players that might emerge as therapeutic targets for cancer or graft-versus-host disease. To knockdown proteins typically involved in the biology of dendritic cells, we employed an siRNA delivery system based on the cationic liposome DOTAP as the carrier. Freshly-isolated CD34(+) cells were transfected with siRNA for cathepsin S with negligible cytotoxicity and transfection rates (>60%) comparable to the efficiency shown by lentiviral vectors. Further, cathepsin S knockdown was performed during both cell commitment and through the entire 14-day differentiation process with repeated transfection rounds that had no effect per se on cell development. Tested in parallel, other commercially-available chemical reagents failed to meet acceptable standards. In addition to safe and practical handling, a direct advantage of DOTAP over viral-mediated techniques is that transient silencing effects can be dynamically appraised through the recovery of targeted proteins. Thus, our findings identify DOTAP as an excellent reagent for gene silencing in resting and differentiating CD34(+) cells, suggesting a potential for applications in related preclinical models.

Pharmacogenomics in Alzheimer's disease

Pharmacological treatment in Alzheimer's disease (AD) accounts for 10-20% of direct costs, and fewer than 20% of AD patients are moderate responders to conventional drugs (donepezil, rivastigmine, galantamine, memantine), with doubtful cost-effectiveness. Both AD pathogenesis and drug metabolism are genetically regulated complex traits in which hundreds of genes cooperatively participate. Structural genomics studies demonstrated that more than 200 genes might be involved in AD pathogenesis regulating dysfunctional genetic networks leading to premature neuronal death. The AD population exhibits a higher genetic variation rate than the control population, with absolute and relative genetic variations of 40-60% and 0.85-1.89%, respectively. AD patients also differ in their genomic architecture from patients with other forms of dementia. Functional genomics studies in AD revealed that age of onset, brain atrophy, cerebrovascular hemodynamics, brain bioelectrical activity, cognitive decline, apoptosis, immune function, lipid metabolism dyshomeostasis, and amyloid deposition are associated with AD-related genes. Pioneering pharmacogenomics studies also demonstrated that the therapeutic response in AD is genotype-specific, with apolipoprotein E (APOE) 4/4 carriers the worst responders to conventional treatments. About 10-20% of Caucasians are carriers of defective cytochrome P450 (CYP) 2D6 polymorphic variants that alter the metabolism and effects of AD drugs and many psychotropic agents currently administered to patients with dementia. There is a moderate accumulation of AD-related genetic variants of risk in CYP2D6 poor metabolizers (PMs) and ultrarapid metabolizers (UMs), who are the worst responders to conventional drugs. The association of the APOE-4 allele with specific genetic variants of other genes (e.g., CYP2D6, angiotensin-converting enzyme [ACE]) negatively modulates the therapeutic response to multifactorial treatments affecting cognition, mood, and behavior. Pharmacogenetic and pharmacogenomic factors may account for 60-90% of drug variability in drug disposition and pharmacodynamics. The incorporation of pharmacogenetic/pharmacogenomic protocols to AD research and clinical practice can foster therapeutics optimization by helping to develop cost-effective pharmaceuticals and improving drug efficacy and safety.

Overview of drug delivery and alternative methods to electroporation

This chapter provides an overview of the application of electroporation to areas other than gene delivery. These areas include the delivery of drugs and vaccines to tissues and tumors as well as into and through the skin. Achievements and limitations of electroporation in these areas are presented. Alternative physical methods for gene and drug delivery besides electroporation are described. The advantages and drawbacks of electroporation, compared with these methods, are also discussed.

A multi-channel electroporation microchip for gene transfection in mammalian cells

We developed a multi-channel electroporation microchip made of polydimethylsiloxane (PDMS) and glass for gene transfer in mammalian cells. This chip produces multiple electric field gradients in a single microchip by varying the lengths of the microchannels from 2 to 4 cm. Electric fields of 0.65, 0.57, 0.49, 0.41, and 0.33 kV/cm were simultaneously produced in a single chip when the voltage of 1.3 kV was applied. We transferred enhanced green fluorescent protein genes (pEGFP) into HEK-293 and CHO cells, which were cultured within the microchannels. The feasibility of our device was demonstrated because it was able to produce five different transfection rates and survival rates at different electric fields produced in a single microchip. This system is expected to optimize the experimental conditions in gene transfection research more easily and faster than conventional electroporation methods.

Rapid and efficient nonviral gene delivery of CD154 to primary chronic lymphocytic leukemia cells

Interactions between CD40 and CD40 ligand (CD154) are essential in the regulation of both humoral and cellular immune responses. Forced expression of human CD154 in B chronic lymphocytic leukemia (B-CLL) cells can upregulate costimulatory and adhesion molecules and restore antigen-presenting capacity. Unfortunately, B-CLL cells are resistant to direct gene manipulation with most currently available gene transfer systems. In this report, we describe the use of a nonviral, clinical-grade, electroporation-based gene delivery system and a standard plasmid carrying CD154 cDNA, which achieved efficient (64+/-15%) and rapid (within 3 h) transfection of primary B-CLL cells. Consistent results were obtained from multiple human donors. Transfection of CD154 was functional in that it led to upregulated expression of CD80, CD86, ICAM-I and MHC class II (HLA-DR) on the B-CLL cells and induction of allogeneic immune responses in MLR assays. Furthermore, sustained transgene expression was demonstrated in long-term cryopreserved transfected cells. This simple and rapid gene delivery technology has been validated under the current Good Manufacturing Practice conditions, and multiple doses of CD154-expressing cells were prepared for CLL patients from one DNA transfection. Vaccination strategies using autologous tumor cells manipulated ex vivo for patients with B-CLL and perhaps with other hematopoietic malignancies could be practically implemented using this rapid and efficient nonviral gene delivery system.

Nucleofection, an efficient nonviral method to transfer genes into human hematopoietic stem and progenitor cells

The targeted manipulation of the genetic program of single cells as well as of complete organisms has strongly enhanced our understanding of cellular and developmental processes and should also help to increase our knowledge of primary human stem cells, e.g., hematopoietic stem cells (HSCs), within the next few years. An essential requirement for such genetic approaches is the existence of a reliable and efficient method to introduce genetic elements into living cells. Retro- and lentiviral techniques are efficient in transducing primary human HSCs, but remain labor and time consuming and require special safety conditions, which do not exist in many laboratories. In our study, we have optimized the nucleofection technology, a modified electroporation strategy, to introduce plasmid DNA into freshly isolated human HSC-enriched CD34(+) cells. Using enhanced green fluorescent protein (eGFP)-encoding plasmids, we obtained transfection efficiencies of approximately 80% and a mean survival rate of 50%. Performing functional assays using GFU-GEMM and long-term culture initiating cells (LTC-IC), we demonstrate that apart from a reduction in the survival rate the nucleofection method itself does not recognizably change the short- or long-term cell fate of primitive hematopoietic cells. Therefore, we conclude, the nucleofection method is a reliable and efficient method to manipulate primitive hematopoietic cells genetically.

Nucleofection-BasedEx VivoNonviral Gene Delivery to Human Stem Cells as a Platform for Tissue Regeneration

There are several gene therapy approaches to tissue regeneration. Although usually efficient, virusbased approaches may elicit an immune response against the viral proteins. An alternative approach, nonviral transfer, is safer, and can be controlled and reproduced. We hypothesized that in vivo bone formation could be achieved using human mesenchymal stem cells (hMSCs) nonvirally transfected with the human bone morphogenetic protein-2 (hBMP-2) or -9 (hBMP-9) gene. Human MSCs were transfected using nucleofection, a unique electropermeabilization-based technique. Postnucleofection, cell viability was 53.6 +/- 2.5% and gene delivery efficiency was 51% to 88% (mean 68.2 +/- 4.1%), as demonstrated by flow cytometry in enhanced green fluorescent protein (EGFP)-nucleofected hMSCs. Transgene expression lasted longer than 14 days and was very low 21 days postnucleofection. Both hBMP-2- and hBMP-9-nucleofected hMSCs in culture demonstrated a significant increase in calcium deposition compared with EGFP-nucleofected hMSCs. Human BMP-2- and hBMP-9-nucleofected hMSCs transplanted in ectopic sites in NOD/SCID mice induced bone formation 4 weeks postinjection. We conclude that in vivo bone formation can be achieved by using nonvirally nucleofected hMSCs. This could lead to a breakthrough in the field of regenerative medicine, in which safer, nonviral therapeutic strategies present a very attractive alternative.

Efficient transient genetic labeling of human CD34+ progenitor cells for in vivo application

Genetic labeling of human hematopoietic progenitor cells (HPC) and their consecutive fate-mapping in vivo is an approach to answer intriguing questions in stem cell biology. We recently reported efficient transient genetic labeling of human CD34+ HPC with the truncated low-affinity nerve growth factor receptor (ΔLNGFR) for in vivo application. Here we investigate whether HPC labeling with ΔLNGFR affects lineage-specific cell differentiation, whether ΔLNGFR expression is maintained during lineage-specific cell differentiation and which leukemia cell line might be an appropriate cell culture model for human CD34+ HPC. Human CD34+ peripheral blood stem cells and various leukemia cell lines were characterized by immunophenotyping. Cells were transfected using nucleofection. Hematopoietic differentiation was studied by colony-forming assays. ΔLNGFR expression was assessed using reverse transcription-PCR, immunofluorescence and flow cytometry. Nucleofection was efficient and did not significantly reduce hematopoietic cell differentiation. Mature myeloid cells (CD66b+) derived from human CD34+ HPC and Mutz2 cells maintained ΔLNGFR expression at a high percentage (70 ± 2% and 58 ± 2%, respectively). Mutz2 cells may serve as an in vitro model for human myeloid HPC. The method described herein has been adopted to Good Manufacturing Practices (GMP) guidelines and is ready for in vivo application.

Genetic modification of hematopoietic stem cells with nonviral systems: past progress and future prospects

Serious unwanted complications provoked by retroviral gene transfer into hematopoietic stem cells (HSCs) have recently raised the need for the development and assessment of alternative gene transfer vectors. Within this context, nonviral gene transfer systems are attracting increasing interest. Their main advantages include low cost, ease of handling and large-scale production, large packaging capacity and, most importantly, biosafety. While nonviral gene transfer into HSCs has been restricted in the past by poor transfection efficiency and transient maintenance, in recent years, biotechnological developments are converting nonviral transfer into a realistic approach for genetic modification of cells of hematopoietic origin. Herein we provide an overview of past accomplishments in the field of nonviral gene transfer into hematopoietic progenitor/stem cells and we point at future challenges. We argue that episomally maintained self-replicating vectors combined with physical methods of delivery show the greatest promise among nonviral gene transfer strategies for the treatment of disorders of the hematopoietic system.

Efficient nonviral gene delivery into primary lymphocytes from rats and mice

A rapid method for efficient gene delivery into primary rodent lymphocytes would greatly facilitate the study of signaling and metabolic pathways in untransformed hematopoietic cells as well as the validation of gene expression and targeting strategies before the generation of knockout or knock-down animals. Here, we report that species-adapted nucleofection procedures combined with optimized cultivation conditions render proliferating primary T cells, B cells, and natural killer cells from widely used rat and mouse strains susceptible to high-level gene delivery. As a result, transgene expression levels were enhanced approximately 10- to 370-fold over established protocols. The effectiveness of the nucleofection approach for functional analyses was demonstrated by specific down-regulation of CD4 cell surface molecules by either transient expression of the endocytosis-inducing Nef protein from human immunodeficiency virus or by specific gene silencing mediated by small interfering RNA. In conclusion, this species-adapted procedure for nonviral gene delivery renders primary rodent lymphocytes accessible to rapid functional ex vivo studies, which until now have not been feasible. Furthermore, nucleofection may aid the advancement of therapeutic nonviral gene delivery approaches.

A novel transfection method for mammalian cells using gas plasma

Introduction of foreign genes into target cells is a crucial step for achievement of gene therapy. We have recently developed a novel transfection system for eukaryotic cells, namely the electric pulse-activated gas plasma generator. To measure the transfection efficiency and mortality by flow-cytometry, we employed enhanced green fluorescent protein and propidium iodide staining, respectively. One day after the 1-3s plasma exposures with DNA concentration at 0.5 microg/microl, favorable transfection efficiencies (17.8-21.6%) and mortalities (0.65-2.86%) were obtained for HeLa-S3, HT-1080 and MCF-7 cells. The recipient cells became transiently permeable for plasmid DNA during the plasma exposure, suggesting that plasma-mediated transfection may involve similar mechanisms that accounts for electroporation. The relatively low mortality rates are encouraging in our attempt to apply this system to the various cell lines including the primary cell cultures.

Gene delivery to embryonic stem cells

Since the establishment of embryonic stem (ES) cells and the identification of tissue-specific stem cells, researchers have made great strides in the analysis of the natural biology of such stem cells for the development of therapeutic applications. Specifically, ES cells are capable of differentiating into all of the cell types that constitute the whole body. Thus, ES cell research promises new type of treatments and possible cures for a variety of debilitating diseases and injuries. The potential medical benefits obtained from stem cell technology are compelling and stem cell research sees a bright future. Control of the growth and differentiation of stem cells is a critical tool in the fields of regenerative medicine, tissue engineering, drug discovery, and toxicity testing. Toward such a goal, we present here an overview of gene delivery in ES cells, covering the following topics: significance of gene delivery in ES cells, stable versus transient gene delivery, cytotoxicity, suspension versus adherent cells, expertise, time, cost, viral vectors for gene transduction (lentiviruses, adenoviruses, and adeno-associated viruses, chemical methods for gene delivery, and mechanical or physical gene delivery methods (electroporation, nucleofection, microinjection, and nuclear transfer).

Diverse effects of nanosecond pulsed electric fields on cells and tissues

The application of pulsed electric fields to cells is extended to include nonthermal pulses with shorter durations (10-300 ns), higher electric fields (< or =350 kV/cm), higher power (gigawatts), and distinct effects (nsPEF) compared to classical electroporation. Here we define effects and explore potential application for nsPEF in biology and medicine. As the pulse duration is decreased below the plasma membrane charging time constant, plasma membrane effects decrease and intracellular effects predominate. NsPEFs induced apoptosis and caspase activation that was calcium-dependent (Jurkat cells) and calcium-independent (HL-60 and Jurkat cells). In mouse B10-2 fibrosarcoma tumors, nsPEFs induced caspase activation and DNA fragmentation ex vivo, and reduced tumor size in vivo. With conditions below thresholds for classical electroporation and apoptosis, nsPEF induced calcium release from intracellular stores and subsequent calcium influx through store-operated channels in the plasma membrane that mimicked purinergic receptor-mediated calcium mobilization. When nsPEF were applied after classical electroporation pulses, GFP reporter gene expression was enhanced above that observed for classical electroporation. These findings indicate that nsPEF extend classical electroporation to include events that primarily affect intracellular structures and functions. Potential applications for nsPEF include inducing apoptosis in cells and tumors, probing signal transduction mechanisms that determine cell fate, and enhancing gene expression.

Effects of daily consumption of honey solution on hematological indices and blood levels of minerals and enzymes in normal individuals

Seven men and three women (mean age, 31.2 years; range, 20-45 years) received a strictly controlled regular diet during a 2-week control period, followed by the regular diet supplemented with daily consumption of 1.2 g/kg body weight honey dissolved in 250 ml of water during a 2-week test period. At the end of each period, overnight fasting blood samples were withdrawn for assays of blood glucose, blood minerals, vitamin C, beta-carotene, uric acid, glutathione reductase, immunoglobulin E, hemoglobin, blood indices and cells, serum ferritin, serum iron, and iron-binding capacity. Results showed that honey increased antioxidant agents. It increased blood vitamin C concentration by 47%, beta-carotene by 3%, uric acid by 12%, and glutathione reductase by 7%. Honey increased serum iron by 20% and decreased plasma ferritin by 11%. It increased the percentage of monocytes by 50%, and increased lymphocyte and eosinophil percentages slightly. Honey reduced serum immunoglobulin E by 34% and increased serum copper by 33%. It decreased aspartate transaminase by 22% and alanine transaminase by 18%. Honey markedly reduced lactic acid dehydrogenase by 41%, decreased creatinine kinase by 33%, and reduced fasting blood sugar by 5%. It caused slight elevations in blood zinc and magnesium, hemoglobin, and packed cell volume. It may be concluded that honey increased antioxidant agents, serum iron and blood indices, and trace elements and decreased immunoglobulin E, liver and muscle enzymes, and fasting blood sugar in healthy subjects.

Natural honey lowers plasma prostaglandin concentrations in normal individuals

Twelve normal, healthy adult individuals, 9 men and 3 women, 25-48 years of age (mean, 38 years), were recruited in the study. After 12 hours of fasting, blood specimens were collected at 8:00 AM for prostaglandin E(2) (PGE(2)), PGF(2alpha), and thromboxane B(2) assays. Each individual then drank 250 ml of water containing 1.2 g/kg body weight of natural unprocessed honey, after which collection of blood was repeated at 1, 2, and 3 hours for estimation of prostaglandins. Each individual was asked to drink the same amount of honey diluted in water once a day for a maximum of 15 days. After 12 hours of fasting, morning blood specimens were collected on day 16, and plasma prostaglandin concentrations were measured. The quantitative analysis of prostaglandins was performed with use of an enzyme-linked immunosorbent (ELISA) test. Results showed that the mean plasma concentration of thromboxane B(2) was reduced by 7%, 34%, and 35%, and that of PGE(2) by 14%, 10%, and 19%, at 1, 2, and 3 hours, respectively, after honey ingestion. The level of PGF(2alpha) was decreased by 31% at 2 hours and 14% at 3 hours after honey ingestion. At day 15, plasma concentrations of thromboxane B(2), PGE(2), and PGF(2a) were decreased by 48%, 63%, and 50%, respectively. It may be concluded that honey can lower the concentrations of prostaglandins in plasma of normal individuals.

Identification of Nitric Oxide Metabolites in Various Honeys: Effects of Intravenous Honey on Plasma and Urinary Nitric Oxide Metabolites Concentrations

Honey has antibacterial activity, promotes healing, and enhances immunity. Its acidity, osmotic effects of its high content of sugar, and hydrogen peroxide are assumed to be responsible for its effects. In this study, various honeys were investigated for the presence of nitrite/nitrate, the stable nitric oxide (NO) metabolites, and the effects of intravenous infusion of honey on urinary and plasma NO end products were studied in healthy sheep. Seven kinds of honey, different in their origin (three from Yemen, two from the United Arab Emirates, one from Germany, and one from India), color, and duration of storage, were investigated for the presence of NO metabolites. The assessment of NO metabolites was performed before and after exposure of the honey samples to heating (80 degrees C for 1 hour) or ultraviolet light (for 24 hours). Seven healthy male sheep were used for the study. Fresh unprocessed yellow honey (2 g/kg of body weight) was infused over a period of 45 minutes to each fasting sheep. Plasma and urinary NO metabolites were measured before and after the infusion. All the honey samples examined had various concentrations of NO metabolites; the highest concentration was in the fresh dark honey collected from Yemen, and the lowest in 1-year-stored dark honey collected from India. Darker or fresh honeys contained more NO metabolites than light or stored honey. After heating, NO metabolites decreased in all the kinds of honey. After ultraviolet exposure, NO metabolites were decreased in four kinds of honey, increased in one kind, and unchanged in two kinds. The darker stored honey had more resistance to heating and ultraviolet exposure. Intravenous infusion of honey elevated urinary NO metabolites from 8.4 +/- 7.4 micromol/L to 14.9 +/- 10 micromol/L during the first 60-90 min after infusion and to 35.2 +/- 34 micromol/L during the next 150-180 min. Plasma NO metabolites were increased during 1, 2, and 3 hours after infusion by 3%, 3.6%, and 17%, respectively. No side effects were reported with the use of intravenous honey. It might be concluded that honey contains various concentrations of NO metabolites. Its intravenous infusion increased plasma and urinary NO metabolites. It is assumed that NO might be responsible, in part, for the biological and therapeutic effects of honey.

Intravenous and Intrapulmonary Administration of Honey Solution to Healthy Sheep: Effects on Blood Sugar, Renal and Liver Function Tests, Bone Marrow Function, Lipid Profile, and Carbon Tetrachloride-Induced Liver Injury

Safety of intravenous (i.v.) or intrapulmonary administration of different concentrations of honey and their effects on blood sugar, renal and liver function tests, bone marrow function, lipid profile, and carbon tetrachloride (CCl(4))-induced liver damage were studied. Healthy sheep of either sex, 6-8 months old, were assigned randomly into the following groups: sheep received i.v. infusion of 5% honey in normal saline at 10-day intervals for 50 days and were compared with sheep that received 5% dextrose; sheep received higher doses of honey (50 g of honey) by i.v. infusion daily for 10 days; sheep received four higher doses of honey (80 g each dose) for 2 weeks; sheep received subcutaneous injection of CCl(4) after four doses of i.v. infusion of 80 g of honey, and estimations of serum gamma-glutamyl transpeptidase (SGGT), serum glutamic oxaloacetic transaminase (SGOT), and serum glutamate pyruvate transaminase (SGPT) were performed daily for 10 days postinjection; sheep received i.v. infusion of 40 g of honey, and blood sugar estimation was performed for 3 h at 30-min intervals after infusion and compared with sheep that received 5% dextrose; sheep received rapid i.v. injection of 40% honey or 40% dextrose, and blood sugar was estimated before and after injection; sheep received various concentrations of honey in distilled water (0.5 mL/1.5 mL, 0.75 mL/1.75 mL and 1.2 mL/2.2 mL), and blood sugar estimation was performed before and after inhalation. Results showed that i.v. or intrapulmonary administration of honey did not cause any adverse effect. Intravenous delivery of honey by slow infusion caused improvement of renal and hepatic function, bone marrow function, and lipid profile. It reduced SGOT, SGPT, triglyceride, cholesterol, blood urea nitrogen, and blood sugar and elevated serum protein, serum albumin, hemoglobin, white blood cell, and neutrophil percentage. Similar results were obtained with the use of higher doses of honey. CCl(4) caused mild elevation of SGPT and SGGT and lowering of SGOT in sheep that received repeated i.v. administration of honey before administration of CCl(4), whereas in control sheep CCl(4) caused significant elevation of all the liver enzymes. Intravenous infusion of 40 g of honey caused elevation of blood sugar for 90 min postinfusion, whereas it decreased blood sugar at 2 and 3 h postinfusion as compared with fasting blood sugar. Dextrose caused significant elevation of blood sugar at all time intervals. Similar results were obtained with the use of 10% dextrose or 80 g of honey. Addition of honey to dextrose caused less hyperglycemia as compared with dextrose alone. Acute injection of 20 mL of 40% dextrose significantly elevated blood sugar for 3 h postinjection, whereas little elevation in blood sugar was obtained after injection of 40% honey; the difference between honey and dextrose was significant. Inhalation of honey caused significant lowering of blood sugar during and after inhalation as compared with fasting blood sugar and water inhalation. The effect was greater with a higher concentration of inhaled honey. It might be concluded that slow i.v. infusion or rapid i.v. injection of honey in different concentrations was safe and could lower blood sugar and improve renal, hepatic, and bone marrow functions and lipid profile. Intravenous honey had a hepatoprotective effect against CCl(4)-induced liver injury. Inhaled honey was safe and reduced blood sugar significantly.

Nanosecond, high-intensity pulsed electric fields induce apoptosis in human cells

Electroporation by using pulsed electric fields with long durations compared with the charging time of the plasma membrane can induce cell fusion or introduce xenomolecules into cells. Nanosecond pulse power technology generates pulses with high-intensity electric fields, but with such short durations that the charging time of the plasma membrane is not reached, but intracellular membranes are affected. To determine more specifically their effects on cell structure and function, human cells were exposed to high intensity (up to 300 kV/cm) nanosecond (10-300 ns) pulsed electric fields (nsPEF) and were analyzed at the cellular and molecular levels. As the pulse duration decreased, plasma membrane electroporation decreased and appearances of apoptosis markers were delayed. NsPEF induced apoptosis within tens of minutes, depending on the pulse duration. Annexin-V binding, caspase activation, decreased forward light scatter, and cytochrome c release into the cytoplasm were coincident. Apoptosis was caspase- and mitochondria-dependent but independent of plasma membrane electroporation and thermal changes. The results suggest that with decreasing pulse durations, nsPEF modulate cell signaling from the plasma membrane to intracellular structures and functions. NsPEF technology provides a unique, high-power, energy-independent tool to recruit plasma membrane and/or intracellular signaling mechanisms that can delete aberrant cells by apoptosis.

Electroporation-mediated ex vivo gene transfer into graft not requiring injection pressure in orthotopic liver transplantation

BACKGROUND

We investigated optimum conditions for ex vivo gene transfer into liver grafts by plasmid injection via the portal vein combined with electroporation in rat liver transplantation.

METHODS

Anesthetized 9-week-old male Shionogi-Wistar rats were used as donors and recipients. After harvest of the liver graft from the donor rat, a tapered 3Fr. catheter was inserted into the portal vein of the liver graft ex vivo. After clamping the afferent vessels around the right and caudal liver lobes, pCAGGS-luciferase, which was diluted with one of several osmotic pressure solutions, or pCAGGS-green fluorescence protein (GFP) plasmid was injected into these lobes to keep the efferent vessels patent. Electrical pulses were applied to the liver graft during cold preservation in lactated Ringer's solution, University of Wisconsin solution, and histidine-tryptophan-ketoglutarate solution.

RESULTS

Transfection efficacy was estimated by measurement of luciferase activity. Luciferase activity in the liver was dependent on both the voltage and electric current of the electrical pulse, and also on the type of preservation solution and plasmid osmotic pressure. Luciferase activity was noted only in plasmid-injected lobes of the liver graft. GFP-transfected cells were identified by GFP fluorescence. GFP was observed predominantly in perivascular cells, including hepatocytes.

CONCLUSIONS

We have demonstrated successful ex vivo gene transfection into liver grafts without injection pressure by using a non-viral method.

Gene transfer in purified human hematopoietic peripheral-blood stem cells by means of electroporation without prestimulation

Gene transfer in hematopoietic stem cells (HSCs) is an important tool, exploring regulation of the hematopoietic system and understanding the development and expansion of malignant cell clones. It is also a mandatory step for gene therapy of hematopoietic disorders. Although retroviral transduction of HSCs is effective, prestimulation of cells is generally required, also inducing differentiation of HSCs. Furthermore, the risk of viral recombination and insertional mutagenesis cannot be ruled out. Potential advantages of nonviral transfection are biosafety and easy management. However, experience in nonviral methods for transfecting peripheral-blood stem cells (PBSCs) is limited. To avoid differentiation, we evaluated the efficiency of gene transfer by means of electroporation without cytokine prestimulation. Compared with prestimulated (stem-cell factor, granulocyte-colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, interleukin-3, interleukin-6, erythropoietin, and monoclonal antibody to transforming growth factor-beta), transfection of thawed nonstimulated PBSCs was equally efficient, with a median transfection rate of 3.7%, transfection efficiency of 0.8%, and survival of 19.5% (n = 5). With freshly isolated HSCs, the rate of transfected cells could be increased to a median of 27.0% (range 8.3%-31.0%), transfection efficiency of 6.9% (range 4.5%-12.6%), and survival of 43% (range 22%-64%) (n = 5). However, the percentage of transfected cells declined with time; almost no cells were detectable by day 11. One cause for the lack of long-term expression of the heterologous gene in this system was induction of apoptosis in transgenic PBSCs, shown by up-regulation of CD95 (FAS antigen).

Highly efficient, large volume flow electroporation

Electroporation is widely used to transfect and load cells with various molecules. Traditional electroporation using a static mode is typically restricted to volumes less than 1 mL, which limits its use in clinical and industrial bioprocessing applications. Here we report efficient, large volume transfection results by using a scalable-volume electroporation system. Suspended (Jurkat) and adherent cells (10T1/2 and Huh-7) were tested. A large macromolecule, FITC-conjugated dextran (MW=500 kD) was used to measure cell uptake, while a plasmid carrying the gene coding for enhanced green fluorescence protein (eGFP) was used to quantitate the flow electrotransfection efficiency as determined by flow cytometry. The flow electroloading efficiency of FITC-dextran was >90%, while the cell viability was highly maintained (>90%). High flow electrotransfection efficiency (up to 75%) and cell viability (up to 90%) were obtained with processing volumes ranging from 1.5 to 50 mL. No significant difference of electrotransfection efficiency was observed between flow and static electrotransfection. When 50 mL of cell volume was processed and samples collected at different time points during electroporation, the transgene expression and cell viability results were identical. We also demonstrated that DNA plasmid containing EBNA1-OriP elements from Epstein-Barr virus were more efficient in transgene expression than standard plasmid without the elements (at least 500 too 1000-fold increase in expression level). Finally, to examine the feasibility of utilizing flow electrotransfected cells as a gene delivery vehicle, 10T1/2 cells were transfected with a DNA plasmid containing the gene coding for mIL12. mIL12 transfected cells were injected subcutaneously into mice, and produced functional mIL12, as demonstrated by anti-angiogenic activity. This is the first demonstration of efficient, large volume, flow electroporation and the in vivo efficacy of flow electrotransfected cells. This technology may be useful for clinical gene therapy and large-scale bioprocesses.

Ozone exposure activates oxidative stress responses in murine skin

Ozone (O(3)) is among the most reactive environmental oxidant to which skin is exposed. O(3) exposure has previously been shown to induce antioxidant depletion as well as lipid and protein oxidation in the outermost skin layer, the stratum corneum (SC), but little is known regarding the potential effects of O(3) on the skin epidermis and dermis. To evaluate such skin responses to O(3), SKH-1 hairless mice were exposed for 2 h to 8.0 ppm O(3) or to ambient air. O(3) exposure caused a significant increase in skin carbonyls (28%) compared to the skin of air exposed control animals. An evident increase in 4-hydroxynonenal-protein adducts was detected after O(3) exposure. O(3) exposure caused a rapid up-regulation of HSP27 (20-fold), and more delayed induction of HSP70 (2.8-fold) and heme oxygenase-1 (5-fold). O(3) exposure also led to the induction of nitric oxide synthase (iNOS) 6-12 h following O(3) exposure. We conclude that skin exposure to high levels of O(3) not only affects antioxidant levels and oxidation markers in the SC, but also induces stress responses in the active layers of the skin, most likely by indirect mechanisms, since it is unlikely that O(3) itself penetrates the protective SC layers.

Pharmacogenomics for the treatment of dementia

Alzheimer's disease (AD) is a genetically complex disorder associated with multiple genetic defects either mutational or of susceptibility. Current AD genetics does not explain in full the etiopathogenesis of AD, suggesting that environmental factors and/or epigenetic phenomena may also contribute to AD pathology and phenotypic expression of dementia. The genomics of AD is still in its infancy, but is helping us to understand novel aspects of the disease including genetic epidemiology, multifactorial risk factors, pathogenic mechanisms associated with genetic networks and genetically-regulated metabolic cascades. AD genomics is also fostering new strategies in pharmacogenomic research and prevention. Functional genomics, proteomics, pharmacogenomics, high-throughput methods, combinatorial chemistry and modern bioinformatics will greatly contribute to accelerating drug development for AD and other complex disorders. The multifactorial genetic dysfunction in AD includes mutational loci (APP, PS1, PS2) and diverse susceptibility loci (APOE, A2M, AACT, LRP1, IL1A, TNF, ACE, BACE, BCHE, CST3, MTHFR, GSK3B, NOS3) distributed across the human genome, probably converging in common pathogenic mechanisms that lead to premature neuronal death. Genomic associations integrate polygenic matrix models to elucidate the genomic organization of AD in comparison to the control population. Using APOE-related monogenic models it has been demonstrated that the therapeutic response to drugs (e.g., cholinesterase inhibitors, non-cholinergic compounds) in AD is genotype-specific. A multifactorial therapy combining three different drugs yielded positive results during 6-12 months in approximately 60% of the patients. With this therapeutic strategy, APOE-4/4 carriers were the worst responders and patients with the APOE-3/4 genotype were the best responders. Other polymorphic variants (PS1, PS2) also influence the therapeutic response to different drugs in AD patients, suggesting that the final pharmacological outcome is the result of multiple genomic interactions, including AD-related genes and genes associated with drug metabolism, disposition, and elimination. The pharmacogenomics of AD may contribute in the future to optimise drug development and therapeutics, increasing efficacy and safety, and reducing side-effects and unnecessary costs.