Current Perspective of Stem Cell Therapy in Neurodegenerative and Metabolic Diseases

Stem cell transplantation therapy for advanced liver damage-associated neurodegenerative disorders

Hepatic encephalopathy and other neurodegenerative disorders have profound implications for extensive liver impairment, calling for new ways of treating the condition. The application of stem cell transplantation to treat these severe disorders is a new and encouraging technique. This review article digs deep into the subject of stem cell transplantation therapy, neurodegenerative disorders associated with advanced liver damage, and liver transplantation. It comprehensively analyses the background, rationale, scope, and objectives of using stem cells to treat such challenging conditions. The topic of discussion includes the subtleties of neurodegenerative disorders, the function of liver transplantation, and the possible advantages and disadvantages associated with it. The relevance of patient selection, intraoperative concerns and post-transplant care is discussed. Further, the article explores how stem cell-based therapies can benefit from nanotechnology, specifically how it can improve stem cell distribution, survival, and integration for better therapeutic results. This review aims to offer a thorough analysis of regenerative medicine's present and future possibilities in dealing with the intricate relationship between neurodegeneration and liver damage. It does this by examining the efficacy, safety, and long-term impacts of stem cell transplantation in treating neurodegenerative disorders associated with advanced liver damage. This will incorporate insights from ongoing clinical trials, the patent landscape, and future directions. The goal is to pave the way for innovative and personalized treatment approaches in this evolving research and clinical practice field. Therefore, these efforts represent a promising frontier in medical research that can alleviate the burden of HE and associated neurological complications combined with liver cirrhosis.

A systematic review of clinical efficacy and safety of cell-based therapies in Alzheimer's disease

There is presently no disease-modifying therapy for Alzheimer's Disease (AD), which is the most prevalent cause of dementia.

Objective

This study aspires to estimate the efficacy and safety of cell-based treatments in AD.

Methods

Observing the Joanna Briggs Institute (JBI) methods and Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, a systematic search was accomplished in PubMed, Medical Literature Analysis and Retrieval System Online (Medline, via Ovid), Embase; Cochrane, and Cumulative Index of Nursing and Allied Health Literature - CINAHL (via EBSCO) databases up to June 2023. The relevant clinical studies in which cell-based therapies were utilized to manage AD were included. The risk of bias was evaluated using the JBI checklists, based on the study designs.

Results

Out of 1,014 screened records, a total of five studies with 70 individuals (including 59 patients receiving stem cells and 11 placebo controls) were included. In all these studies, despite the discrepancy in the origin of stem cells, cell density, and transplant site, safety goals were obtained. The intracerebroventricular injection of adipose-derived stromal vascular fraction (ADSVF) and umbilical cord-derived mesenchymal stem cells (UC-MSCs), the intravenous injection of Lomecel-B, and the bilateral hippocampi and right precuneus injection of UC-MSCs are not linked to any significant safety concerns, according to the five included studies. Studies also revealed improvements in biomarkers and clinical outcomes as a secondary outcome. Three studies had no control groups and there are concerns regarding the similarity of the groups in others. Also, there is considerable risk of bias regarding the outcome assessment scales.

Conclusion

Cell-based therapies are well tolerated by AD patients, which emphasizes the need for further, carefully planned randomized studies to reach evidence-based clinical recommendations in this respect.

Flavonoids in Combination with Stem Cells for the Treatment of Neurological Disorders

Neurological disorders are the leading cause of disability and the world's second leading cause of death. Despite the availability of significant knowledge to reduce the burden of some neurological disorders, various studies are exploring more effective treatment options. While the human body can repair and regenerate damaged tissue through stem cell recruitment, nerve regeneration in case of injury is minimal due to the restriction on the location of nerve stem cells. Recently, different types of stem cells extracted from various tissues have been used in combination with natural stimuli to treat neurologic disorders in neuronal tissue engineering. Flavonoids are polyphenolic compounds that can induce the differentiation of stem cells into neurons and stimulate stem cell proliferation, migration, and survival. They can also increase the secretion of nutritional factors from stem cells. In addition to the effects that flavonoids can have on stem cells, they can also have beneficial therapeutic effects on the nervous system alone. Therefore, the simultaneous use of these compounds and stem cells can multiply the therapeutic effect. In this review, we first introduce flavonoid compounds and provide background information on stem cells. We then compile available reports on the effects of flavonoids on stem cells for the treatment of neurological disorders.

Effect of substrate charge density on the adsorption of intrinsically disordered protein amyloid β40: a molecular dynamics study

The inhibitory effect of negatively charged gold nanoparticles (AuNPs) on amyloidogenic protein fibrillation has been established from experiments and computer simulations. Here, we investigate the effect of the charge density (σ) of gold (Au) surfaces on the adsorption of the intrinsically disordered amyloid β40 (Aβ40) monomer using molecular dynamics (MD) simulations. On the basis of the binding free energy, some key residues (ARG5, LYS16, LYS28, LEU17-ALA21, ILE31-VAL38) were found to be responsible for preventing the β-sheet formation, which is known to be a precursor for fibrillation. Until a critical charge density (σ_c) of -0.167 e nm^-2, the key residues remained adsorbed on the Au slab. A saturation in the number of condensed counterions (Na⁺) on Aβ40 was also observed at σ_c. Beyond σ_c, the condensation of Na⁺ occurs only on the Au slab, leading to competition between positively charged key residues and condensed ions. This competition was found to be responsible for the lack of adsorption of the key residues, leading to β-sheet formation for σ > -0.167 e nm^-2. This study suggests that if the key residues are not adsorbed, then β-sheet formation is observed, which can then lead to the development of proto-fibrils and subsequently fibrillation. Therefore the surface should have an optimal charge density to be an effective inhibitor of fibrillation.

Nanotherapeutic and Stem Cell Therapeutic Strategies in Neurodegenerative Diseases: A Promising Therapeutic Approach

Neurodegeneration is characterized by progressive, disabling, and incurable neurological disorders with the massive loss of specific neurons. As one of the most promising potential therapeutic strategies for neurodegenerative diseases, stem cell therapy exerts beneficial effects through different mechanisms, such as direct replacement of damaged or lost cells, secretion of neurotrophic and growth factors, decreased neuroinflammation, and activation of endogenous stem cells. However, poor survival and differentiation rates of transplanted stem cells, insufficient homing ability, and difficulty tracking after transplantation limit their further clinical use. The rapid development of nanotechnology provides many promising nanomaterials for biomedical applications, which already have many applications in neurodegenerative disease treatment and seem to be able to compensate for some of the deficiencies in stem cell therapy, such as transport of stem cells/genes/drugs, regulating stem cell differentiation, and real-time tracking in stem cell therapy. Therefore, nanotherapeutic strategies combined with stem cell therapy is a promising therapeutic approach to treating neurodegenerative diseases. The present review systematically summarizes recent advances in stem cell therapeutics and nanotherapeutic strategies and highlights how they can be combined to improve therapeutic efficacy for the treatment of neurodegenerative diseases.

Mitochondrial Dysfunction Contributes To Zinc-induced Neurodegeneration: a Link with NADPH Oxidase

Mitochondrial dysfunction and nicotinamide adenine dinucleotide phosphate oxidase (NADPH oxidase) are the major sources of augmentation in free radical generation leading to neurodegeneration. Although NADPH oxidase involvement is reported in zinc (Zn)-induced neurodegeneration, contribution of the mitochondrial dysfunction and its association with NADPH oxidase are not known. Therefore, the study was aimed to decipher the role of mitochondrial dysfunction and its link with NADPH oxidase in Zn-induced Parkinsonism. Zn reduced the motor activities, the number of tyrosine hydroxylase (TH)-positive neurons, and level of TH protein. Conversely, Zn increased the mitochondrial reactive oxygen species (ROS) production, lipid peroxidation (LPO), and superoxide dismutase (SOD) activity and reduced the mitochondrial membrane potential and catalytic activities of complex I and III. Zn also attenuated B-cell lymphoma-2 (Bcl-2) and pro-caspase 9/3 levels and augmented the translocation of cytosolic Bcl-2 associated X (Bax) protein to the mitochondria and cytochrome c release into cytosol from the mitochondria. Cyclosporine A, a mitochondrial outer membrane transition pore inhibitor and apocynin, a NADPH oxidase inhibitor, independently, ameliorated the Zn-induced changes. Similarly, Zn reduced cell viability through mitochondrial dysfunction and apoptosis in human neuroblastoma SH-SY5Y cells, which were notably normalized in the presence of cyclosporine or apocynin. The results demonstrate that mitochondrial dysfunction contributes to Zn-induced neurodegeneration, which could be partially aided by the NADPH oxidase.

Mesenchymal Stem Cells in the Treatment of New Coronavirus Pandemic: A Novel Promising Therapeutic Approach

After severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) outbreaks, coronavirus disease 2019 (COVID-19) is the third coronavirus epidemic that soon turned into a pandemic. This virus causes acute respiratory syndrome in infected people. The mortality rate of SARS-CoV-2 infection will probably rise unless efficient treatments or vaccines are developed. The global funding and medical communities have started performing more than five hundred clinical examinations on a broad spectrum of repurposed drugs to acquire effective treatments. Besides, other novel treatment approaches have also recently emerged, including cellular host-directed therapies. They counteract the unwanted responses of the host immune system that led to the severe pathogenesis of SARS-CoV-2. This brief review focuses on mesenchymal stem cell (MSC) principles in treating the COVID-19. The US clinical trials database and the world health organization database for clinical trials have reported 82 clinical trials (altogether) exploring the effects of MSCs in COVID-19 treatment. MSCs also had better be tried for treating other pathogens worldwide. MSC treatment may have the potential to end the high mortality rate of COVID-19. Besides, it also limits the long-term inability of survivors.

Nanotheranostic agents for neurodegenerative diseases

Neurodegenerative diseases (NDDs), including Alzheimer's disease (AD) and Parkinson's disease (PD), affect the ageing population worldwide and while severely impairing the quality of life of millions, they also cause a massive economic burden to countries with progressively ageing populations. Parallel with the search for biomarkers for early detection and prediction, the pursuit for therapeutic approaches has become growingly intensive in recent years. Various prospective therapeutic approaches have been explored with an emphasis on early prevention and protection, including, but not limited to, gene therapy, stem cell therapy, immunotherapy and radiotherapy. Many pharmacological interventions have proved to be promising novel avenues, but successful applications are often hampered by the poor delivery of the therapeutics across the blood-brain-barrier (BBB). To overcome this challenge, nanoparticle (NP)-mediated drug delivery has been considered as a promising option, as NP-based drug delivery systems can be functionalized to target specific cell surface receptors and to achieve controlled and long-term release of therapeutics to the target tissue. The usefulness of NPs for loading and delivering of drugs has been extensively studied in the context of NDDs, and their biological efficacy has been demonstrated in numerous preclinical animal models. Efforts have also been made towards the development of NPs which can be used for targeting the BBB and various cell types in the brain. The main focus of this review is to briefly discuss the advantages of functionalized NPs as promising theranostic agents for the diagnosis and therapy of NDDs. We also summarize the results of diverse studies that specifically investigated the usage of different NPs for the treatment of NDDs, with a specific emphasis on AD and PD, and the associated pathophysiological changes. Finally, we offer perspectives on the existing challenges of using NPs as theranostic agents and possible futuristic approaches to improve them.

Adsorption of the amyloid β40 monomer on charged gold nanoparticles and slabs: a molecular dynamics study

Negatively charged nanoparticles are known to inhibit the fibrillation of amyloidogenic protein amyloid β (Aβ40), though the overall charge on the protein is negative. In this work a molecular dynamics study is reported to investigate the interaction of Aβ40 on negatively charged gold nanoparticles (3-5 nm) and charged (positive and negative) and neutral gold slabs. The equilibrium structures of Aβ40 on gold surfaces are characterized using residue-specific contacts on the gold surface, secondary structure analysis and binding free energy calculations. The simulation results reveal that the Aβ40 protein in water interconverts into β-sheets, which are building blocks of the mature fibrils, whereas on gold nanoparticles Aβ40 unfolds and adsorbs. Both the negatively charged gold nanoparticles and gold slabs arrest the formation of β-sheets in Aβ40, whereas the positively charged gold slab does not inhibit the formation of β-sheets. The residue-specific interactions between Aβ40 and the gold surfaces are important in governing the adsorption of Aβ40 on charged surfaces.

Mesenchymal stem cells act as stimulators of neurogenesis and synaptic function in a rat model of Alzheimer's disease

BACKGROUND

Alzheimer's disease (AD) is one of the most common NDs leading to cognitive dysfunctions and dementia which are progressively worsen with age. Cell therapy is currently of particular interest in treatment of neurodegenerative disease (ND) such as AD. However, the effective treatment for AD is yet to be found.

OBJECTIVE

In this study, the possible roles of human umbilical mesnchymal stromal cord (hUMSCs) and adipose mesenchymal stem cells (hAD-MSCs) in neurogenesis and synaptic function were investigated using a β-amyloid 1-42 (β A42)-induced AD rat model.

METHODS

hUMSCs and hAD-MSCs were isolated from umbilical cord stroma and adipose tissue, respectively. The expression of Mesenchymal (CD73, CD90 and CD105) and hematopoietic (CD45 and CD133) markers of hUMSCs and hAD-MSCs were confirmed by flow cytometry. Alzheimer's rat model was created by β-amyloid 1-42 injection into the hippocampus and confirmed by Morris Water Maze and immunohistochemical staining. hUMSCs and hAD-MSCs were injected in Alzheimer's rat model, intravenously. Deposition of β-amyloid in the CA1 of hippocampus was assayed 3 months after cell administration. The expression of synaptophysin and GAP43 proteins was assessed by Western blot. Neural death was assessed by Nissl staining.

RESULTS

The data obtained from flow cytometry showed that surface mesenchymal and hematopoteic markers of the fibroblastic like cells isolated from adipose tissue and umbilical cord were expressed highly in hUMSCs and mostly in hAD-SCs. Transplantation of MSCs reduced β-amyloid deposition in the hippocampus of the AD rats compared to the β-amyloid group. The rate of neuronal cell death in the hippocampus of the β-amyloid-treated rats was significantly increased compared to that of the control group. The percentage of apoptotic cells in this group was 72.98 ± 1.25, which was significantly increased compared to the control group. Transplantation of either hUMSCs or hAD-SCs, respectively, resulted in a significant reduction in the apoptotic rate of the neuronal cells in the hippocampus by 39.47 ± 0.01 (p = 0.0001) and 43.23 ± 0.577 (p = 0.001) compared to the β-amyloid group. MSC transplantation resulted in a significant up-regulation in the expression levels of both synaptogenic (synaptophysin) and neurogenic markers (GAP43) by 1.289 ± 0.112 (P = 0.02) and 1.112 ± 0.106 (P = 0.005) fold in the hUMSCs-treated group and 1.174 ± 0.105 (P = 0.04) and 0.978 ± 0.167 (P = 0.008) fold in the hAD-SCs-treated group, respectively.

CONCLUSION

Intravenous injection of hUMSCs and hAD-MSCs is a safe approach that improves synaptic function and neurogenesis via up-regulation of synaptophysin and GAP43 protein expression levels, respectively, in Alzheimer's model. Intravenous injection of both applied SCs could improve learning and cognitive impairment induced by β A42 injection.

Small molecular compounds efficiently convert human fibroblasts directly into neurons

No effective treatment is currently available for neurodegenerative diseases, and existing pharmacotherapy is inconsistent with severe side effects. Cell replacement therapy is promising for neurodegenerative disease treatment, and the induction of neurons is an unmet need for such therapy. The present study investigated the potential of a combined medium composed of conditioned medium and eight small molecular compounds in reprogramming human foreskin fibroblasts (HFFs) into neurons. HFFs were cultured from foreskin and then induced by small molecules to generate neurons. The results demonstrated that the conditioned medium containing forskolin, RepSox, SP600125, CHIR99021, Go6983, Y-27632, IXS9 and I-BET151 effectively induced human fibroblasts to change into neurons in vitro. Following a 30-day induction, the cells exhibited neuronal properties as determined by morphological and phenotypical alterations. The induced cells exhibited expression of neuronal markers, including class III β-tubulin, microtubule-associated protein 2, vesicular glutamate transporter 1 and γ-aminobutyric acid, accompanied by increased expression of neuronal transcription factors, including neuronal differentiation 1 and achaete-scute family bHLH transcription factor 1, and decreased expression levels of fibroblast-specific genes. Furthermore, these cells also exhibited electrophysiological properties of neurons. Notably, the course of cell morphological alterations demonstrated the differentiation of fibroblasts into neurons. The present study provided a novel combination of existing small molecular compounds that efficiently reprogramed human fibroblasts into neurons.

Nanotheranostic Applications for Detection and Targeting Neurodegenerative Diseases

Nanotechnology utilizes engineered materials and devices which function with biological systems at the molecular level and could transform the management of neurodegenerative diseases (NDs) by provoking, reacting to, and intermingling with target sites to stimulate physiological responses while minimizing side effects. Blood-brain barrier (BBB) protects the brain from harmful agents, and transporting drugs across the BBB is a major challenge for diagnosis, targeting, and treatment of NDs. The BBB provides severe limitations for diagnosis and treatment of Alzheimer's disease (AD), Parkinson's disease (PD), and various other neurological diseases. Conventional drug delivery systems generally fail to cross the BBB, thus are inefficient in treatment. Although gradual development through research is ensuring the progress of nanotheranostic approaches from animal to human modeling, aspects of translational applicability and safety are a key concern. This demands a deep understanding of the interaction of body systems with nanomaterials. There are various plant-based nanobioactive compounds which are reported to have applicability in the diagnosis and treatment of these NDs. This review article provides an overview of applications of nanotheranostics in AD and PD. The review also discusses nano-enabled drug delivery systems and their current and potential applications for the treatment of various NDs.

Embryonic Cerebellar Graft Morphology Differs in Two Mouse Models of Cerebellar Degeneration

Cerebellar diseases causing substantial cell loss often lead to severe functional deficits and restoration of cerebellar function is difficult. Neurotransplantation therapy could become a hopeful method, but there are still many limitations and unknown aspects. Studies in a variety of cerebellar mutant mice reflecting heterogeneity of human cerebellar degenerations show promising results as well as new problems and questions to be answered. The aim of this work was to compare the development of embryonic cerebellar grafts in adult B6CBA Lurcher and B6.BR pcd mutant mice and strain-matched healthy wild type mice. Performance in the rotarod test, graft survival, structure, and volume was examined 2 months after the transplantation or sham-operation. The grafts survived in most of the mice of all types. In both B6CBA and B6.BR wild type mice and in pcd mice, colonization of the host's cerebellum was a common finding, while in Lurcher mice, the grafts showed a low tendency to infiltrate the host's cerebellar tissue. There were no significant differences in graft volume between mutant and wild type mice. Nevertheless, B6CBA mice had smaller grafts than their B6.BR counterparts. The transplantation did not improve the performance in the rotarod test. The study showed marked differences in graft integration into the host's cerebellum in two types of cerebellar mutants, suggesting disease-specific factors influencing graft fate.

Recent Advances in the Treatment of Cerebellar Disorders

Various etiopathologies affect the cerebellum, resulting in the development of cerebellar ataxias (CAs), a heterogeneous group of disorders characterized clinically by movement incoordination, affective dysregulation, and cognitive dysmetria. Recent progress in clinical and basic research has opened the door of the ‘‘era of therapy” of CAs. The therapeutic rationale of cerebellar diseases takes into account the capacity of the cerebellum to compensate for pathology and restoration, which is collectively termed cerebellar reserve. In general, treatments of CAs are classified into two categories: cause-cure treatments, aimed at arresting disease progression, and neuromodulation therapies, aimed at potentiating cerebellar reserve. Both forms of therapies should be introduced as soon as possible, at a time where cerebellar reserve is still preserved. Clinical studies have established evidence-based cause-cure treatments for metabolic and immune-mediated CAs. Elaborate protocols of rehabilitation and non-invasive cerebellar stimulation facilitate cerebellar reserve, leading to recovery in the case of controllable pathologies (metabolic and immune-mediated CAs) and delay of disease progression in the case of uncontrollable pathologies (degenerative CAs). Furthermore, recent advances in molecular biology have encouraged the development of new forms of therapies: the molecular targeting therapy, which manipulates impaired RNA or proteins, and the neurotransplantation therapy, which delays cell degeneration and facilitates compensatory functions. The present review focuses on the therapeutic rationales of these recently developed therapeutic modalities, highlighting the underlying pathogenesis.

Task Force Paper On Cerebellar Transplantation: Are We Ready to Treat Cerebellar Disorders with Cell Therapy?

Restoration of damaged central nervous system structures, functional recovery, and prevention of neuronal loss during neurodegenerative diseases are major objectives in cerebellar research. The highly organized anatomical structure of the cerebellum with numerous inputs/outputs, the complexity of cerebellar functions, and the large spectrum of cerebellar ataxias render therapies of cerebellar disorders highly challenging. There are currently several therapeutic approaches including motor rehabilitation, neuroprotective drugs, non-invasive cerebellar stimulation, molecularly based therapy targeting pathogenesis of the disease, and neurotransplantation. We discuss the goals and possible beneficial mechanisms of transplantation therapy for cerebellar damage and its limitations and factors determining outcome.

Anthocyanins and Their Metabolites as Therapeutic Agents for Neurodegenerative Disease

Neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis (ALS), are characterized by the death of neurons within specific regions of the brain or spinal cord. While the etiology of many neurodegenerative diseases remains elusive, several factors are thought to contribute to the neurodegenerative process, such as oxidative and nitrosative stress, excitotoxicity, endoplasmic reticulum stress, protein aggregation, and neuroinflammation. These processes culminate in the death of vulnerable neuronal populations, which manifests symptomatically as cognitive and/or motor impairments. Until recently, most treatments for these disorders have targeted single aspects of disease pathology; however, this strategy has proved largely ineffective, and focus has now turned towards therapeutics which target multiple aspects underlying neurodegeneration. Anthocyanins are unique flavonoid compounds that have been shown to modulate several of the factors contributing to neuronal death, and interest in their use as therapeutics for neurodegeneration has grown in recent years. Additionally, due to observations that the bioavailability of anthocyanins is low relative to that of their metabolites, it has been proposed that anthocyanin metabolites may play a significant part in mediating the beneficial effects of an anthocyanin-rich diet. Thus, in this review, we will explore the evidence evaluating the neuroprotective and therapeutic potential of anthocyanins and their common metabolites for treating neurodegenerative diseases.

Magnetic Force-Based Microfluidic Techniques for Cellular and Tissue Bioengineering

Live cell manipulation is an important biotechnological tool for cellular and tissue level bioengineering applications due to its capacity for guiding cells for separation, isolation, concentration, and patterning. Magnetic force-based cell manipulation methods offer several advantages, such as low adverse effects on cell viability and low interference with the cellular environment. Furthermore, magnetic-based operations can be readily combined with microfluidic principles by precisely allowing control over the spatiotemporal distribution of physical and chemical factors for cell manipulation. In this review, we present recent applications of magnetic force-based cell manipulation in cellular and tissue bioengineering with an emphasis on applications with microfluidic components. Following an introduction of the theoretical background of magnetic manipulation, components of magnetic force-based cell manipulation systems are described. Thereafter, different applications, including separation of certain cell fractions, enrichment of rare cells, and guidance of cells into specific macro- or micro-arrangements to mimic natural cell organization and function, are explained. Finally, we discuss the current challenges and limitations of magnetic cell manipulation technologies in microfluidic devices with an outlook on future developments in the field.

Precise nanoinjection delivery of plasmid DNA into a single fibroblast for direct conversion of astrocyte

Direct conversion is a powerful approach to safely generate mature neural lineages with potential for treatment of neurological disorders. Astrocytes play a crucial role in neuronal homeostasis and their dysfunctions contribute to several neurodegenerative diseases. Using a single-cell approach for precision, we describe here a robust method using optimized DNA amounts for the direct conversion of mouse fibroblasts to astrocytes. Controlled amount of the reprogramming factors Oct4, Sox2, Klf4 and cMyc was directly delivered into a single fibroblast cell. Consequently, 2500 DNA molecules, no more or less, were found to be the optimal amount that dramatically increased the expression levels of the astrocyte-specific markers GFAP and S100b and the demethylation gene TET1, the expression of which was sustained to maintain astrocyte functionality. The converted astrocytes showed glutamate uptake ability and electrophysiological activity. Furthermore, we demonstrated a potential mechanism whereby fibroblast was directly converted into astrocyte at a single-cell level; this was achieved by activating BMP2 pathway through direct binding of Sox2 protein to BMP2 gene. This study suggests that nanotechnology for directly injecting plasmid DNAs into cell nuclei may help understand such a conversion at single-cell level.

Myt1l induced direct reprogramming of pericytes into cholinergic neurons

OBJECTIVE

The cholinergic deficit is thought to underlie progressed cognitive decline in Alzheimer Disease. The lineage reprogramming of somatic cells into cholinergic neurons may provide strategies toward cell-based therapy of neurodegenerative diseases.

METHODS AND RESULTS

Here, we found that a combination of neuronal transcription factors, including Ascl1, Myt1l, Brn2, Tlx3, and miR124 (5Fs) were capable of directly converting human brain vascular pericytes (HBVPs) into cholinergic neuronal cells. Intriguingly, the inducible effect screening of reprogramming factors showed that a single reprogramming factor, Myt1l, induced cells to exhibit similarly positive staining for Tuj1, MAP2, ChAT, and VAChT upon lentivirus infection with the 5Fs after 30 days. HBVP-converted neurons were rarely labeled even after long-term incubation with BrdU staining, suggesting that induced neurons were directly converted from HBVPs rather than passing through a proliferative state. In addition, the overexpression of Myt1l induced the elevation of Ascl1, Brn2, and Ngn2 levels that contributed to reprogramming.

CONCLUSIONS

Our findings provided proof of the principle that cholinergic neurons could be produced from HBVPs by reprogramming factor-mediated fate instruction. Myt1l was a critical mediator of induced neuron cell reprogramming. HBVPs represent another excellent alternative cell resource for cell-based therapy to treat neurodegenerative disease.

Tiny But Mighty: Promising Roles of MicroRNAs in the Diagnosis and Treatment of Parkinson's Disease

Parkinson's disease (PD) is the second most common age-related neurodegenerative disorder after Alzheimer's disease. To date, the clinical diagnosis of PD is primarily based on the late onset of motor impairments. Unfortunately, at this stage, most of the dopaminergic neurons may have already been lost, leading to the limited clinical benefits of current therapeutics. Therefore, early identification of PD, especially at the prodromal stage, is still a main challenge in the diagnosis and management of this disease. Recently, microRNAs (miRNAs) in cerebrospinal fluid or peripheral blood have been proposed as putative biomarkers to assist in PD diagnosis and therapy. In this review, we systematically summarize the changes of miRNA expression profiles in PD patients, and highlight their putative roles in the diagnosis and treatment of this devastating disease.

Stem Cells and Other Emerging Agents as Innovative "Drugs" in Neurodegenerative Diseases: Benefits and Limitations

The brain has a limited process of repair/regeneration linked to the restricted and localized activity of neuronal stem cells. Consequently, it shows a reduced capacity to counteract the age-related loss of neural and glial cells and to repair the consequent injuries/lesions of nervous system. This progressively determines nervous dysfunction and onset/progression of neurodegenerative diseases, which represent a serious social (and economic) problem of our populations. Thus, the research of efficient treatments is encouraged. Stem cell therapy might represent a solution. Today, it, indeed, represents the object of intensive research with the hope of using it, in a near future, as effective therapy for these diseases and preventive treatment in susceptible individuals. Here, we report and discuss the data of the recent studies on this field, underling the obstacles and benefits. We also illustrate alternative measures of intervention, which represent another parallel aim for the care of neurodegenerative pathology-affected individuals. Thus, the road for delaying or retarding these diseases appears hard and long, but the advances might be different.

From Blood to Lesioned Brain: An In Vitro Study on Migration Mechanisms of Human Nasal Olfactory Stem Cells

Stem cell-based therapies critically rely on selective cell migration toward pathological or injured areas. We previously demonstrated that human olfactory ectomesenchymal stem cells (OE-MSCs), derived from an adult olfactory lamina propria, migrate specifically toward an injured mouse hippocampus after transplantation in the cerebrospinal fluid and promote functional recoveries. However, the mechanisms controlling their recruitment and homing remain elusive. Using an in vitro model of blood-brain barrier (BBB) and secretome analysis, we observed that OE-MSCs produce numerous proteins allowing them to cross the endothelial wall. Then, pan-genomic DNA microarrays identified signaling molecules that lesioned mouse hippocampus overexpressed. Among the most upregulated cytokines, both recombinant SPP1/osteopontin and CCL2/MCP-1 stimulate OE-MSC migration whereas only CCL2 exerts a chemotactic effect. Additionally, OE-MSCs express SPP1 receptors but not the CCL2 cognate receptor, suggesting a CCR2-independent pathway through other CCR receptors. These results confirm that OE-MSCs can be attracted by chemotactic cytokines overexpressed in inflamed areas and demonstrate that CCL2 is an important factor that could promote OE-MSC engraftment, suggesting improvement for future clinical trials.

Protein aggregation, misfolding and consequential human neurodegenerative diseases

Proteins are major components of the biological functions in a cell. Biology demands that a protein must fold into its stable three-dimensional structure to become functional. In an unfavorable cellular environment, protein may get misfolded resulting in its aggregation. These conformational disorders are directly related to the tissue damage resulting in cellular dysfunction giving rise to different diseases. This way, several neurodegenerative diseases such as Alzheimer, Parkinson Huntington diseases and amyotrophic lateral sclerosis are caused. Misfolding of the protein is prevented by innate molecular chaperones of different classes. It is envisaged that work on this line is likely to translate the knowledge into the development of possible strategies for early diagnosis and efficient management of such related human diseases. The present review deals with the human neurodegenerative diseases caused due to the protein misfolding highlighting pathomechanisms and therapeutic intervention.

Advances in Monitoring Cell-Based Therapies with Magnetic Resonance Imaging: Future Perspectives

Cell-based therapies are currently being developed for applications in both regenerative medicine and in oncology. Preclinical, translational, and clinical research on cell-based therapies will benefit tremendously from novel imaging approaches that enable the effective monitoring of the delivery, survival, migration, biodistribution, and integration of transplanted cells. Magnetic resonance imaging (MRI) offers several advantages over other imaging modalities for elucidating the fate of transplanted cells both preclinically and clinically. These advantages include the ability to image transplanted cells longitudinally at high spatial resolution without exposure to ionizing radiation, and the possibility to co-register anatomical structures with molecular processes and functional changes. However, since cellular MRI is still in its infancy, it currently faces a number of challenges, which provide avenues for future research and development. In this review, we describe the basic principle of cell-tracking with MRI; explain the different approaches currently used to monitor cell-based therapies; describe currently available MRI contrast generation mechanisms and strategies for monitoring transplanted cells; discuss some of the challenges in tracking transplanted cells; and suggest future research directions.

Potential of Induced Pluripotent Stem Cells (iPSCs) for Treating Age-Related Macular Degeneration (AMD)

The field of stem cell biology has rapidly evolved in the last few decades. In the area of regenerative medicine, clinical applications using stem cells hold the potential to be a powerful tool in the treatment of a wide variety of diseases, in particular, disorders of the eye. Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) are promising technologies that can potentially provide an unlimited source of cells for cell replacement therapy in the treatment of retinal degenerative disorders such as age-related macular degeneration (AMD), Stargardt disease, and other disorders. ESCs and iPSCs have been used to generate retinal pigment epithelium (RPE) cells and their functional behavior has been tested in vitro and in vivo in animal models. Additionally, iPSC-derived RPE cells provide an autologous source of cells for therapeutic use, as well as allow for novel approaches in disease modeling and drug development platforms. Clinical trials are currently testing the safety and efficacy of these cells in patients with AMD. In this review, the current status of iPSC disease modeling of AMD is discussed, as well as the challenges and potential of this technology as a viable option for cell replacement therapy in retinal degeneration.