Production of dopaminergic neurons for cell therapy in the treatment of Parkinson's disease

Combining NT3-overexpressing MSCs and PLGA microcarriers for brain tissue engineering: A potential tool for treatment of Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder that characterized by destruction of substantia nigrostriatal pathway due to the loss of dopaminergic (DA) neurons. Regardless of substantial efforts for treatment of PD in recent years, an effective therapeutic strategy is still missing. In a multidisciplinary approach, bone marrow derived mesenchymal stem cells (BMSCs) are genetically engineered to overexpress neurotrophin-3 (nt-3 gene) that protect central nervous system tissues and stimulates neuronal-like differentiation of BMSCs. Poly(lactic-co-glycolic acid) (PLGA) microcarriers are designed as an injectable scaffold and synthesized via double emulsion method. The surface of PLGA microcarriers are functionalized by collagen as a bioadhesive agent for improved cell attachment. The results demonstrate effective overexpression of NT-3. The expression of tyrosine hydroxylase (TH) in transfected BMSCs reveal that NT-3 promotes the intracellular signaling pathway of DA neuron differentiation. It is also shown that transfected BMSCs are successfully attached to the surface of microcarriers. The presence of dopamine in peripheral media of cell/microcarrier complex reveals that BMSCs are successfully differentiated into dopaminergic neuron. Our approach that sustains presence of growth factor can be suggested as a novel complementary therapeutic strategy for treatment of Parkinson disease.

Stem cell-derived dopamine neurons for brain repair in Parkinson’s disease

One of the prospects for a curative treatment for Parkinson’s disease is to replace the lost dopaminergic neurons. Preclinical and clinical trials have demonstrated that dissected fetal dopaminergic neurons have the potential to markedly improve motor function in animal models and Parkinson’s disease patients. However, this source of cells will never be sufficient to use as a widespread therapy. Over the last 20 years, scientists have been searching for other reliable sources of midbrain dopamine neurons, and stem cells appear to be strong candidates. This article reviews the potential of different types of stem cells, from embryonic to adult to induced pluripotent stem cells, to see how well the cells can be differentiated into fully functional dopamine neurons, which cells might be the best candidates and how much more research is required before stem cell technology might be translated to a clinical therapy for Parkinson’s disease.

Dopaminergic properties and function after grafting of attached neural precursor cultures

Generation of dopaminergic (DA) neurons from multipotent embryonic progenitors represents a promising therapeutical strategy for Parkinson's disease (PD). Aim of the present study was the establishment of enhanced cell culture conditions, which optimize the use of midbrain progenitor cells in animal models of PD. In addition, the progenitor cells were characterized during expansion and differentiation according to morphological and electrophysiological criteria and compared to primary tissue. Here, we report that CNS precursors can be expanded in vitro up to 40-fold and afterwards be efficiently differentiated into DA neurons. After 4-5 days under differentiation conditions, more than 70% of the neurons were TH+, equivalent to 30% of the total cell population. Calcium imaging revealed the presence of calcium-permeable AMPA receptors in the differentiated precursors which are capable to contribute to many developmental processes. The overall survival rate, degree of reinnervation and the behavioral performance after transplantation of 4 days in-vitro-differentiated cells were similar to results after direct grafting of E14 ventral mesencephalic cells, whereas after shorter or longer differentiation periods, respectively, less effects were achieved. Compared to the amount of in-vitro-generated DA neurons, the survival rate was only 0.8%, indicating that these cells are very vulnerable. Our results suggest that expanded and differentiated DA precursors from attached cultures can survive microtransplantation and integrate within the striatum in terms of behavioral recovery. However, there is only a short time window during in vitro differentiation, in which enough cells are already differentiated towards a DA phenotype and simultaneously not too mature for implantation. However, additional factors and/or genetical manipulation of these expanded progenitors will be required to increase their in vivo survival in order to improve both the ethical and the technical outlook for the use of fetal tissue in clinical transplantation.

Biomedical Imaging Research Opportunities Workshop III: A White Paper

The third Biomedical Imaging Research Opportunities Workshop (BIROW III) was held on March 11-12, 2005, in Bethesda, MD. The workshop addressed four areas of imaging that present opportunities for research and development: Multimodality Image-Guided Therapy, Imaging Informatics, Imaging Cell Trafficking, and Technology Improvement and Commercialization. The first three areas were individually addressed in their own plenary sessions, followed by audience discussions that explored research opportunities and challenges. This paper synthesizes these discussions into a strategy for future research directions in biomedical imaging.

New therapeutic approaches to Parkinson's disease including neural transplants

Parkinson's disease (PD) is a common neurodegenerative disorder of the brain and typically presents with a disorder of movement. The core pathological event underlying the condition is the loss of the dopaminergic nigrostriatal pathway with the formation of alpha-synuclein positive Lewy bodies. As a result, drugs that target the degenerating dopaminergic network within the brain work well at least in the early stages of the disease. Unfortunately, with time these therapies fail and produce their own unique side-effect profile, and this, coupled with the more diffuse pathological and clinical findings in advancing disease, has led to a search for more effective therapies. In this review, the authors will briefly discuss the emerging new drug therapies in PD before concentrating on a more detailed discussion on the state of cell therapies to cure PD.

Molecular MR imaging in oncology

The implementation and integration of systems biology approaches with the emerging nanosciences and microchip technology will revolutionize profoundly molecular imaging and fuel the drive toward a more predictive and individualized health care. In combination with informatics platforms, key gene and protein targets will be identified, and serve as more effective targets for diagnostic and therapeutic interventions. Drug development also will be expedited by the judicious selection of more appropriate molecular biomarkers that will serve as objective end points of treatment efficacy, in addition to facilitating the development of new target-specific therapeutics. Finally, with the more widespread proliferation of high-field magnets and advancements in imaging hardware; acquisition methods; and novel,"smart" MR agents, the ability to achieve higher resolution analyses of tumor biology, cell track-ing, and gene expression will be realized more fully. Although radiologists will continue to serve as diagnostic consultants and assist in management decisions, the contributions from new developments in the biologic and molecular sciences will significantly alter the scope of our profession. Radiologists will be required to participate more actively in the individualized care of the patient and cultivate a deeper understanding of the underlying molecular basis of disease and molecular pharmacology for facilitating selection of the most appropriate combination of imaging studies that address biologically relevant questions. These radical changes in our profession will necessitate the re-education and emergence of a small cadre of professionals that is educated broadly in multiple scientific disciplines, and demonstrate expertise in clinical care and the basic sciences. The optimistic view is that this already is happening.

Donor age affects differentiation of rat ventral mesencephalic stem cells

This study examined the effect of gestational age of rat ventral mesencephalon (VM) on the characteristics of neurospheres generated from this region and on the yield of each cell type after differentiation of these neurospheres. Neurospheres generated from embryonic day (E) 12 and E13 VM had significantly larger diameters and volumes than those from E14 VM. Subsequent differentiation of these neurospheres resulted in decreasing yield of neurones (E12>E13>E14) and increasing yields of both astroglia and oligodendroglia (E12<E13<E14) with increasing donor age. Dopaminergic neurones were generated in low numbers from E12 and E13 cultures, and were virtually absent in E14 cultures. This study suggests that gestational age is a critical factor in the selection of tissue to generate particular cell types from neural stem cells. This has important implications for the use of neural stem cells in transplantation approaches to neurodegenerative diseases.

Intracerebral transplantation of carotid body in rats with transient middle cerebral artery occlusion

Recent laboratory and clinical studies demonstrate therapeutic efficacy of intracerebral transplantation of carotid body (CB) in Parkinson's disease, possibly through secretion of neurotrophic factors. Here, we examined the role of CB in experimental stroke. In the first experiment, we hypothesized that removal of CB would exacerbate cerebral infarction and stroke-related behavioral deficits. Eight-week-old, male Sprague-Dawley rats were randomly divided into two groups: stroke with intact CB and stroke with surgically removed CB. We used the stroke model of temporary middle cerebral artery occlusion. The ipsilateral CB was removed in animals assigned to treatment group exposed to stroke with surgically removed CB. Behavioral tests, using the elevated body swing test, were conducted at days 1-3 after surgery. Cerebral infarction was visualized by TTC staining on day 3 post-surgery. The data revealed no significant differences in behavioral deficits and infarct volumes between the two groups. In the second experiment, CB cell suspension grafts or control adult tissue grafts were intracerebally transplanted into the ischemic penumbra immediately (within 1 h) after stroke surgery. The results revealed significant reduction of behavioral deficits and infarct volumes, accompanied by increased levels of neurotrophic factors, as detected by ELISA, in transplanted ischemic striatum collected from CB-grafted stroke animals. These observations suggest that surgical resection of CB in the periphery did not alter stroke pathology; however, CB when made available in the CNS, via intracerebral transplantation, could protect against stroke possibly through the synergistic release of neurotrophic factors. The present study extends the use of CB as efficacious graft source for transplantation.

Molecular imaging of cell-based therapies

This article focuses on molecular imaging of novel cell-based therapies, particularly stem cell therapies and the adoptive transfer of immunocytes. The animal models,potential clinical applications, and likely future prospects of these therapies are discussed in the context of imaging.

Discovering novel phenotype-selective neurotrophic factors to treat neurodegenerative diseases

Astrocytes and neurons in the central nervous system (CNS) interact functionally to mediate processes as diverse as neuroprotection, neurogenesis and synaptogenesis. Moreover, the interaction can be homotypic, implying that astrocyte-derived secreted molecules affect their adjacent neurons optimally vs remote neurons. Astrocytes produce neurotrophic and extracellular matrix molecules that affect neuronal growth, development and survival, synaptic development, stabilization and functioning, and neurogenesis. This new knowledge offers the opportunity of developing astrocyte-derived, secreted proteins as a new class of therapeutics specifically to treat diseases of the CNS. However, primary astrocytes proliferate slowly in vitro, and when induced to immortalize by genetic manipulation, tend to lose their phenotype. These problems have limited the development of astrocytes as sources of potential drug candidates. We have successfully developed a method to induce spontaneous immortalization of astrocytes. Gene expression analysis, karyotyping and activity profiling data show that these spontaneously immortalized type-1 astrocyte cell lines retain the properties of their primary parents. The method is generic, such that cell lines can be prepared from any region of the CNS. To date, a library of 70 cell lines from four regions of the CNS: ventral mesencephalon, striatum, cerebral cortex and hippocampus, has been created. A phenotype-selective neurotrophic factor for dopaminergic neurons has been discovered from one of the cell lines (VMCL1). This mesencephalic astrocyte-derived neurotrophic factor (MANF) is a 20 kD, glycosylated, human secreted protein. Homologs of this protein have been identified in 16 other species including C. elegans. These new developments offer the opportunity of creating a library of astrocyte-derived molecules, and developing the ones with the best therapeutic indices for clinical use.

MANF: a new mesencephalic, astrocyte-derived neurotrophic factor with selectivity for dopaminergic neurons

We describe the discovery of a novel, 20 kDa, secreted human protein named mesencephalic astrocyte-derived neurotrophic factor, or MANF. The homologous, native molecule was initially derived from a rat mesencephalic type-1 astrocyte cell line and recombinant MANF subcloned from a cDNA encoding human arginine-rich protein. MANF selectively protects nigral dopaminergic neurons, versus GABAergic or serotonergic neurons. The discovery of MANF marks a more systematic approach in the search for astrocyte-derived, secreted proteins that selectively protect specific neuronal phenotypes. Compared to glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF), MANF was more selective in the protection of dopaminergic neurons at lower (0.05-0.25 ng/mL) and middle (0.5-2.5 ng/mL) concentrations: MANF>GDNF>BDNF. GDNF was more selective at higher concentrations (25-50 ng/ml): GDNF>MANF>BDNF. Two domains in MANF of 39-AA and 109-AA respectively, and eight cysteines are conserved from C. elegans to man. MANF is encoded by a 4.3 Kb gene with 4 exons, and is located on the short arm of human chromosome 3. The secondary structure is dominated by alpha-helices (47%) and random coils (37%). Studies to determine the localization of MANF in the brains of rat, monkey, and man, as well as the receptor, signaling pathways, and biologically active peptide mimetics are in progress. The selective, neuroprotective effect of MANF for dopaminergic neurons suggests that it may be indicated for the treatment of Parkinson's disease.

MANF: a new mesencephalic, astrocyte-derived neurotrophic factor with selectivity for dopaminergic neurons

We describe the discovery of a novel, 20 kDa, secreted human protein named mesencephalic astrocyte-derived neurotrophic factor, or MANF. The homologous, native molecule was initially derived from a rat mesencephalic type-1 astrocyte cell line and recombinant MANF subcloned from a cDNA encoding human arginine-rich protein. MANF selectively protects nigral dopaminergic neurons, versus GABAergic or serotonergic neurons. The discovery of MANF marks a more systematic approach in the search for astrocyte-derived, secreted proteins that selectively protect specific neuronal phenotypes. Compared to glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF), MANF was more selective in the protection of dopaminergic neurons at lower (0.05-0.25 ng/mL) and middle (0.5-2.5 ng/mL) concentrations: MANF>GDNF>BDNF. GDNF was more selective at higher concentrations (25-50 ng/ml): GDNF>MANF>BDNF. Two domains in MANF of 39-AA and 109-AA respectively, and eight cysteines are conserved from C. elegans to man. MANF is encoded by a 4.3 Kb gene with 4 exons, and is located on the short arm of human chromosome 3. The secondary structure is dominated by alpha-helices (47%) and random coils (37%). Studies to determine the localization of MANF in the brains of rat, monkey, and man, as well as the receptor, signaling pathways, and biologically active peptide mimetics are in progress. The selective, neuroprotective effect of MANF for dopaminergic neurons suggests that it may be indicated for the treatment of Parkinson's disease.

MANF: a new mesencephalic, astrocyte-derived neurotrophic factor with selectivity for dopaminergic neurons

We describe the discovery of a novel, 20 kDa, secreted human protein named mesencephalic astrocyte-derived neurotrophic factor, or MANF. The homologous, native molecule was initially derived from a rat mesencephalic type-1 astrocyte cell line and recombinant MANF subcloned from a cDNA encoding human arginine-rich protein. MANF selectively protects nigral dopaminergic neurons, versus GABAergic or serotonergic neurons. The discovery of MANF marks a more systematic approach in the search for astrocyte-derived, secreted proteins that selectively protect specific neuronal phenotypes. Compared to glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF), MANF was more selective in the protection of dopaminergic neurons at lower (0.05-0.25 ng/mL) and middle (0.5-2.5 ng/mL) concentrations: MANF>GDNF>BDNF. GDNF was more selective at higher concentrations (25-50 ng/ml): GDNF>MANF>BDNF. Two domains in MANF of 39-AA and 109-AA respectively, and eight cysteines are conserved from C. elegans to man. MANF is encoded by a 4.3 Kb gene with 4 exons, and is located on the short arm of human chromosome 3. The secondary structure is dominated by alpha-helices (47%) and random coils (37%). Studies to determine the localization of MANF in the brains of rat, monkey, and man, as well as the receptor, signaling pathways, and biologically active peptide mimetics are in progress. The selective, neuroprotective effect of MANF for dopaminergic neurons suggests that it may be indicated for the treatment of Parkinson's disease.