The regulatory roles of microRNAs toward pathogenesis and treatments in Huntington's disease.

Huntington's disease (HD) is one of neurodegenerative diseases, and is defined as a monogenetic disease due to the mutation of Huntingtin gene. This disease affects several cellular functions in neurons, and further influences motor and cognitive ability, leading to the suffering of devastating symptoms in HD patients. MicroRNA (miRNA) is a non-coding RNA, and is responsible for gene regulation at post-transcriptional levels in cells. Since one miRNA targets to several downstream genes, it may regulate different pathways simultaneously. As a result, it raises a potential therapy for different diseases using miRNAs, especially for inherited diseases. In this review, we will not only introduce the update information of HD and miRNA, but also discuss the development of potential miRNA-based therapy in HD. With the understanding toward the progression of miRNA studies in HD, we anticipate it may provide an insight to treat this devastating disease, even applying to other genetic diseases.

Fibroblast Growth Factor 9 Suppresses Striatal Cell Death Dominantly Through ERK Signaling in Huntington's Disease.

BACKGROUND/AIMS: Huntington's disease (HD) is a heritable neurodegenerative disorder, and there is no cure for HD to date. A type of fibroblast growth factor (FGF), FGF9, has been reported to play prosurvival roles in other neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease. However, the effects of FGF9 on HD is still unknown. With many similarities in the cellular and pathological mechanisms that eventually cause cell death in neurodegenerative diseases, we hypothesize that FGF9 might provide neuroprotective functions in HD. METHODS: In this study, STHdhQ7/Q7 (WT) and STHdhQ111/Q111 (HD) striatal knock-in cell lines were used to evaluate the neuroprotective effects of FGF9. Cell proliferation, cell death and neuroprotective markers were determined via the MTT assay, propidium iodide staining and Western blotting, respectively. The signaling pathways regulated by FGF9 were demonstrated using Western blotting. Additionally, HD transgenic mouse models were used to further confirm the neuroprotective effects of FGF9 via ELISA, Western blotting and immunostaining. RESULTS: Results show that FGF9 not only enhances cell proliferation, but also alleviates cell death as cells under starvation stress. In addition, FGF9 significantly upregulates glial cell line-derived neurotrophic factor (GDNF) and an anti-apoptotic marker, Bcl-xL, and decreases the expression level of an apoptotic marker, cleaved caspase 3. Furthermore, FGF9 functions through ERK, AKT and JNK pathways. Especially, ERK pathway plays a critical role to influence the effects of FGF9 toward cell survival and GDNF production. CONCLUSIONS: These results not only show the neuroprotective effects of FGF9, but also clarify the critical mechanisms in HD cells, further providing an insight for the therapeutic potential of FGF9 in HD.

miR-196a ameliorates phenotypes of Huntington disease in cell, transgenic mouse, and induced pluripotent stem cell models.

Huntington disease (HD) is a dominantly inherited neurodegenerative disorder characterized by dysregulation of various genes. Recently, microRNAs (miRNAs) have been reported to be involved in this dysregulation, suggesting that manipulation of appropriate miRNA regulation may have a therapeutic benefit. Here, we report the beneficial effects of miR-196a (miR196a) on HD in cell, transgenic mouse models, and human induced pluripotent stem cells derived from one individual with HD (HD-iPSCs). In the in vitro results, a reduction of mutant HTT and pathological aggregates, accompanying the overexpression of miR-196a, was observed in HD models of human embryonic kidney cells and mouse neuroblastoma cells. In the in vivo model, HD transgenic mice overexpressing miR-196a revealed the suppression of mutant HTT in the brain and also showed improvements in neuropathological progression, such as decreases of nuclear, intranuclear, and neuropil aggregates and late-stage behavioral phenotypes. Most importantly, miR-196a also decreased HTT expression and pathological aggregates when HD-iPSCs were differentiated into the neuronal stage. Mechanisms of miR-196a in HD might be through the alteration of ubiquitin-proteasome systems, gliosis, cAMP response element-binding protein pathway, and several neuronal regulatory pathways in vivo. Taken together, these results show that manipulating miR-196a provides beneficial effects in HD, suggesting the potential therapeutical role of miR-196a in HD.

Towards a transgenic model of Huntington's disease in a non-human primate.

Non-human primates are valuable for modelling human disorders and for developing therapeutic strategies; however, little work has been reported in establishing transgenic non-human primate models of human diseases. Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by motor impairment, cognitive deterioration and psychiatric disturbances followed by death within 10-15 years of the onset of the symptoms. HD is caused by the expansion of cytosine-adenine-guanine (CAG, translated into glutamine) trinucleotide repeats in the first exon of the human huntingtin (HTT) gene. Mutant HTT with expanded polyglutamine (polyQ) is widely expressed in the brain and peripheral tissues, but causes selective neurodegeneration that is most prominent in the striatum and cortex of the brain. Although rodent models of HD have been developed, these models do not satisfactorily parallel the brain changes and behavioural features observed in HD patients. Because of the close physiological, neurological and genetic similarities between humans and higher primates, monkeys can serve as very useful models for understanding human physiology and diseases. Here we report our progress in developing a transgenic model of HD in a rhesus macaque that expresses polyglutamine-expanded HTT. Hallmark features of HD, including nuclear inclusions and neuropil aggregates, were observed in the brains of the HD transgenic monkeys. Additionally, the transgenic monkeys showed important clinical features of HD, including dystonia and chorea. A transgenic HD monkey model may open the way to understanding the underlying biology of HD better, and to the development of potential therapies. Moreover, our data suggest that it will be feasible to generate valuable non-human primate models of HD and possibly other human genetic diseases.

Overexpression of Smad proteins, especially Smad7, in oral epithelial dysplasias.

OBJECTIVE: Transforming growth factor ß, via membrane-bound receptors and downstream Smad2-4, 7, can modulate tumorigenesis. Smad2 and Smad3 heterodimerize with Smad4, and the complex migrates to the nucleus to regulate the expression of target genes. Smad7 is a key negative regulator of this signaling pathway. This study aimed to examine Smad2-4, 7 expression and phosphorylated Smad2-3 (p-Smad2-3) in oral epithelial dysplasia and compared it with normal oral mucosa, hyperkeratosis/epithelial hyperplasia and squamous cell carcinoma (SCC). MATERIALS AND METHODS: Immunohistochemical staining of Smad2-4, 7 and p-Smad2-3, was performed for 75 samples of human oral mucosa, including hyperkeratosis/epithelial hyperplasia (n = 20), mild epithelial dysplasia (n = 11), moderate to severe epithelial dysplasia (n = 11), and SCC (n = 43). Normal buccal mucosa samples (n = 9) were also included. RESULTS: A significant increase in Smad7 expression was observed in the ascending order of samples of normal oral mucosa, hyperkeratosis/epithelial hyperplasia/mild oral epithelial dysplasia, moderate to severe oral epithelial dysplasia, and well-differentiated oral SCC/moderately to poorly differentiated oral SCC. Additionally, significant increases in Smad7 expression were noted as compared with expression of Smad2-4 and p-Smad2-3 in lesions of hyperkeratosis/epithelial hyperplasia, mild oral epithelial dysplasia, moderate to severe oral epithelial dysplasia, well-differentiated oral SCC, and moderately to poorly differentiated oral SCC. CONCLUSIONS: Our results indicate that Smad proteins, particularly Smad7, in oral epithelial dysplasia and SCC could contribute to the attenuation of Smads anti-proliferative signaling in cancer development. CLINICAL RELEVANCE: Smad7 could be a marker for risk of malignant transformation of oral epithelial dysplasia.

miR-196a provides antioxidative neuroprotection via USP15/Nrf2 regulation in Huntington's disease.

Huntington's disease (HD) is a devastating neurodegenerative disorder characterized by the accumulation of mutant Huntingtin protein (mHTT) and oxidative stress-induced neuronal damage. Based on previous reports, microRNA-196a (miR-196a) has emerged as a potential therapeutic target due to its neuroprotective effects in various neurodegenerative diseases. However, whether miR-196a functions through antioxidative effects is still unknown. In this study, we demonstrated that HD models, both in vitro and in vivo, exhibit elevated levels of reactive oxygen species (ROS) and increased neuronal death, and miR-196a mitigates ROS levels and reduces cell death in HD cells. Moreover, we elucidated that miR-196a facilitates the translocation of nuclear factor erythroid 2 (Nrf2) into the nucleus, enhancing the transcription of antioxidant genes, including heme oxygenase-1 (HO-1). We further identified ubiquitin-specific peptidase 15 (USP15), a direct target of miR-196a related to the Nrf2 pathway, and USP15 exacerbates mHTT aggregate formation while partially counteracting miR-196a-induced reductions in mHTT levels. Taken together, these findings shed light on the multifaceted role of miR-196a in HD, highlighting its potential as a therapeutic avenue for ameliorating oxidative stress and neurodegeneration in this debilitating disease.

miR-196a enhances polymerization of neuronal microfilaments through suppressing IMP3 and upregulating IGF2 in Huntington's disease.

Huntington's disease (HD) is one of the inheritable neurodegenerative diseases, and these diseases share several similar pathological characteristics, such as abnormal neuronal morphology. miR-196a is a potential target to provide neuroprotective functions, and has been reported to enhance polymerization of neuronal microtubules in HD. While microtubules and microfilaments are two important components of the neuronal cytoskeleton, whether miR-196a improves neuronal microfilaments is still unknown. Here, we identify insulin-like growth factor 2 mRNA binding protein 3 (IMP3), and show that miR-196a directly suppresses IMP3 to increase neurite outgrowth in neurons. In addition, IMP3 disturbs neurite outgrowth in vitro and in vivo, and worsens the microfilament polymerization. Moreover, insulin-like growth factor-II (IGF2) is identified as the downstream target of IMP3, and miR-196a downregulates IMP3 to upregulate IGF2, which increases microfilamental filopodia numbers and activates Cdc42 to increase neurite outgrowth. Besides, miR-196a increases neurite outgrowth through IGF2 in different HD models. Finally, higher expression of IMP3 and lower expression IGF2 are observed in HD transgenic mice and patients, and increase the formation of aggregates in the HD cell model. Taken together, miR-196a enhances polymerization of neuronal microfilaments through suppressing IMP3 and upregulating IGF2 in HD, supporting the neuroprotective functions of miR-196a through neuronal cytoskeleton in HD.

Characterization of dental pulp stem/stromal cells of Huntington monkey tooth germs.

BACKGROUND: Dental pulp stem/stromal cells (DPSCs) are categorized as adult stem cells (ASCs) that retain multipotent differentiation capabilities. DPSCs can be isolated from individuals at any age and are considered to be true personal stem cells, making DPSCs one of the potential options for stem cell therapy. However, the properties of DPSCs from individuals with an inherited genetic disorder, such as Huntington's disease (HD), have not been fully investigated. RESULTS: To examine if mutant huntingtin (htt) protein impacts DPSC properties, we have established DPSCs from tooth germ of transgenic monkeys that expressed both mutant htt and green fluorescent protein (GFP) genes (rHD/G-DPSCs), and from a monkey that expressed only the GFP gene (rG-DPSCs), which served as a control. Although mutant htt and oligomeric htt aggregates were overtly present in rHD/G-DPSCs, all rHD/G-DPSCs and rG-DPSCs shared similar characteristics, including self-renewal, multipotent differentiation capabilities, expression of stemness and differentiation markers, and cell surface antigen profile. CONCLUSIONS: Our results suggest that DPSCs from Huntington monkeys retain ASC properties. Thus DPSCs derived from individuals with genetic disorders such as HD could be a potential source of personal stem cells for therapeutic purposes.

Fibroblast Growth Factor 9 Stimulates Neuronal Length Through NF-kB Signaling in Striatal Cell Huntington's Disease Models.

Proper development of neuronal cells is important for brain functions, and impairment of neuronal development may lead to neuronal disorders, implying that improvement in neuronal development may be a therapeutic direction for these diseases. Huntington's disease (HD) is a neurodegenerative disease characterized by impairment of neuronal structures, ultimately leading to neuronal death and dysfunctions of the central nervous system. Based on previous studies, fibroblast growth factor 9 (FGF9) may provide neuroprotective functions in HD, and FGFs may enhance neuronal development and neurite outgrowth. However, whether FGF9 can provide neuronal protective functions through improvement of neuronal morphology in HD is still unclear. Here, we study the effects of FGF9 on neuronal length in HD and attempt to understand the related working mechanisms. Taking advantage of striatal cell lines from HD knock-in mice, we found that FGF9 increases total neuronal length and upregulates several structural and synaptic proteins under HD conditions. In addition, activation of nuclear factor kappa B (NF-kB) signaling by FGF9 was observed to be significant in HD cells, and blockage of NF-kB leads to suppression of these structural and synaptic proteins induced by FGF9, suggesting the involvement of NF-kB signaling in these effects of FGF9. Taken these results together, FGF9 may enhance total neuronal length through upregulation of NF-kB signaling, and this mechanism could serve as an important mechanism for neuroprotective functions of FGF9 in HD.

FGF9 induces neurite outgrowth upon ERK signaling in knock-in striatal Huntington's disease cells.

AIMS: Huntington's disease (HD) is a neurodegenerative disease that causes deficits in neurite outgrowth, which suggests that enhancement of neurite outgrowth is a potential direction by which to improve HD. Our previous publications showed that fibroblast growth factor 9 (FGF9) provides anti-apoptosis and anti-oxidative functions in striatal cell models of HD through the extracellular signal-regulated kinases (ERK) pathway, and FGF9 also stimulates cytoskeletons to enhance neurite outgrowth via nuclear factor kappa B (NF-kB) signaling. In this study, we further demonstrate the importance of the ERK pathway for the neurite outgrowth induced by FGF9 in HD striatal models. MATERIALS AND METHODS: FGF9 was treated with ERK (U0126) or NF-kB (BAY11-7082) inhibitors in STHdhQ7/Q7 and STHdhQ111/Q111 striatal knock-in cell lines to examine neurite outgrowth, cytoskeletal markers, and synaptic proteins via immunofluorescence staining and Western blotting. NF-kB activity was analyzed by NF-kB promoter reporter assay. KEY FINDINGS: Here, we show that suppression of ERK signaling significantly inhibits FGF9-induced neurite outgrowth, cytoskeletal markers, and synaptic proteins in HD striatal cells. In addition, we also show suppression of ERK signaling significantly decreases FGF9-induced NF-kB activation, whereas suppression of NF-kB does not decrease FGF9-induced ERK signaling. These results suggest that FGF9 activates ERK signaling first, stimulates NF-kB upregulation, and then enhances neurite outgrowth in HD striatal cells. SIGNIFICANCE: We elucidate the more detailed mechanisms of neurite outgrowth enhanced by FGF9 in these HD striatal cells. This study may provide insights into targeting neurite outgrowth for HD therapy.

Monkey hybrid stem cells develop cellular features of Huntington's disease.

BACKGROUND: Pluripotent stem cells that are capable of differentiating into different cell types and develop robust hallmark cellular features are useful tools for clarifying the impact of developmental events on neurodegenerative diseases such as Huntington's disease. Additionally, a Huntington's cell model that develops robust pathological features of Huntington's disease would be valuable for drug discovery research. RESULTS: To test this hypothesis, a pluripotent Huntington's disease monkey hybrid cell line (TrES1) was established from a tetraploid Huntington's disease monkey blastocyst generated by the fusion of transgenic Huntington's monkey skin fibroblast and a wild-type non-transgenic monkey oocyte. The TrES1 developed key Huntington's disease cellular pathological features that paralleled neural development. It expressed mutant huntingtin and stem cell markers, was capable of differentiating to neural cells, and developed teratoma in severely compromised immune deficient (SCID) mice. Interestingly, the expression of mutant htt, the accumulation of oligomeric mutant htt and the formation of intranuclear inclusions paralleled neural development in vitro , and even mutant htt was ubiquitously expressed. This suggests the development of Huntington's disease cellular features is influenced by neural developmental events. CONCLUSIONS: Huntington's disease cellular features is influenced by neural developmental events. These results are the first to demonstrate that a pluripotent stem cell line is able to mimic Huntington's disease progression that parallels neural development, which could be a useful cell model for investigating the developmental impact on Huntington's disease pathogenesis.

Putative dental pulp-derived stem/stromal cells promote proliferation and differentiation of endogenous neural cells in the hippocampus of mice.

Until now, interest in dental pulp stem/stromal cell (DPSC) research has centered on mineralization and tooth repair. Beginning a new paradigm in DPSC research, we grafted undifferentiated, untreated DPSCs into the hippocampus of immune-suppressed mice. The rhesus DPSC (rDPSC) line used was established from the dental pulp of rhesus macaques and found to be similar to human bone marrow/mesenchymal stem cells, which express Nanog, Rex-1, Oct-4, and various cell surface antigens, and have multipotent differentiation capability. Implantation of rDPSCs into the hippocampus of mice stimulated proliferation of endogenous neural cells and resulted in the recruitment of pre-existing Nestin(+) neural progenitor cells (NPCs) and beta-tubulin-III(+) mature neurons to the site of the graft. Additionally, many cells born during the first 7 days after implantation proliferated, forming NPCs and neurons, and, to a lesser extent, underwent astrogliosis, forming astrocytes and microglia, by 30 days after implantation. Although the DPSC graft itself was short term, it had long-term effects by promoting growth factor signaling. Implantation of DPSCs enhanced the expression of ciliary neurotrophic factor, vascular endothelial growth factor, and fibroblast growth factor for up to 30 days after implantation. In conclusion, grafting rDPSCs promotes proliferation, cell recruitment, and maturation of endogenous stem/progenitor cells by modulating the local microenvironment. Our results suggest that DPSCs have a valuable, unique therapeutic potential, specifically as a stimulator and modulator of the local repair response in the central nervous system. DPSCs would be a preferable cell source for therapy due to the possibility of a "personalized" stem cell, avoiding the problems associated with host immune rejection. Disclosure of potential conflicts of interest is found at the end of this article.

Fibroblast growth factor 9 activates anti-oxidative functions of Nrf2 through ERK signalling in striatal cell models of Huntington's disease.

Huntington's disease (HD) is a heritable neurodegenerative disorder, and has been characterized as an increase of oxidative stress in brain regions. In our previous results, we showed fibroblast growth factor 9 (FGF9) provides neuroprotective functions to suppress cell death in HD striatal cells dominantly through ERK signalling. However, whether the working mechanism of FGF9 is related to anti-oxidative stress in HD is still unknown. In this study, STHdhQ7/Q7 (Q7) and STHdhQ111/Q111 (Q111) striatal knock-in cell lines were used to examine the neuroprotective effects of FGF9 against oxidative stress in HD. Results show that FGF9 alleviates oxidative stress induced by starvation in Q7 and Q111 cells. The treatment of FGF9 not only induces upregulation and activation of nuclear factor erythroid 2-like 2 (Nrf2), a critical transcription factor for anti-oxidative stress, but also further upregulates its downstream targets, such as superoxide dismutase 2, gamma-glutamylcysteine synthetase and glutathione reductase. Furthermore, blockage of the Nrf2 pathway abolishes the anti-oxidative functions of FGF9, and inhibition of ERK signalling reduces the activation of the FGF9-Nrf2 pathway, resulting in higher level of oxidative stress in HD cells. These results support the neuroprotective effects of FGF9 against oxidative stress through the ERK-Nrf2 pathway, and imply one of potential strategies for therapy of HD.

Lentiviral integration preferences in transgenic mice.

Lentiviral gene transfer has a significant impact on the development of biomedical research. One of the most important features of lentiviruses is the capability to infect both dividing and nondividing cells. However, little is known whether integration preference exists, specifically in early embryos. An in-depth genome analysis on 112 independent lentiviral integration sites from 43 transgenic founder mice was performed to determine if there are preferable sites for lentiviral integration in early embryonic genome. Our results demonstrated that lentiviruses were biased in integrating within intragenic regions, especially in the introns. However, no integration preference was found associated with specific chromosomes, repetitive elements, or CpG islands, nor was there any preference for integrating at close proximity to transcription start sites. Our findings suggested that lentiviruses were biased to integrate into the intragenic regions of early embryonic genome of mouse.

Postnatal stem/progenitor cells derived from the dental pulp of adult chimpanzee.

BACKGROUND: Chimpanzee dental pulp stem/stromal cells (ChDPSCs) are very similar to human bone marrow derived mesenchymal stem/stromal cells (hBMSCs) as demonstrated by the expression pattern of cell surface markers and their multipotent differentiation capability. RESULTS: ChDPSCs were isolated from an incisor and a canine of a forty-seven year old female chimpanzee. A homogenous population of ChDPSCs was established in early culture at a high proliferation rate and verified by the expression pattern of thirteen cell surface markers. The ChDPSCs are multipotent and were capable of differentiating into osteogenic, adipogenic and chondrogenic lineages under appropriate in vitro culture conditions. ChDPSCs also express stem cell (Sox-2, Nanog, Rex-1, Oct-4) and osteogenic (Osteonectin, osteocalcin, osteopontin) markers, which is comparable to reported results of rhesus monkey BMSCs (rBMSCs), hBMSCs and hDPSCs. Although ChDPSCs vigorously proliferated during the initial phase and gradually decreased in subsequent passages, the telomere length indicated that telomerase activity was not significantly reduced. CONCLUSION: These results demonstrate that ChDPSCs can be efficiently isolated from post-mortem teeth of adult chimpanzees and are multipotent. Due to the almost identical genome composition of humans and chimpanzees, there is an emergent need for defining the new role of chimpanzee modeling in comparative medicine. Teeth are easy to recover at necropsy and easy to preserve prior to the retrieval of dental pulp for stem/stromal cells isolation. Therefore, the establishment of ChDPSCs would preserve and maximize the applications of such a unique and invaluable animal model, and could advance the understanding of cellular functions and differentiation control of adult stem cells in higher primates.

miR-196a Enhances Neuronal Morphology through Suppressing RANBP10 to Provide Neuroprotection in Huntington's Disease.

MicroRNAs (miRNAs) play important roles in several neurobiological processes, including the development and progression of diseases. Previously, we identified that one specific miRNA, miR-196a, provides neuroprotective effects on Huntington's disease (HD), although the detailed mechanism is still unclear. Based on our bioinformatic analyses, we hypothesize miR-196a might offer neuroprotective functions through improving cytoskeletons of brain cells. Here, we show that miR-196a could enhance neuronal morphology, further ameliorating intracellular transport, synaptic plasticity, neuronal activity, and learning and memory abilities. Additionally, we found that miR-196a could suppress the expression of RAN binding protein 10 (RANBP10) through binding to its 3' untranslated region, and higher expression of RANBP10 exacerbates neuronal morphology and intracellular transport. Furthermore, miR-196a enhances neuronal morphology through suppressing RANBP10 and increasing the ability of ß-tubulin polymerization. Most importantly, we observed higher expression of RANBP10 in the brains of HD transgenic mice, and higher expression of RANBP10 might exacerbate the pathological aggregates in HD. Taken together, we provide evidence that enhancement of neuronal morphology through RANBP10 is one of the neuroprotective mechanisms for miR-196a. Since miR-196a has also been reported in other neuronal diseases, this study might offer insights with regard to the therapeutic use of miR-196a in other neuronal diseases.

The Truncated C-terminal Fragment of Mutant ATXN3 Disrupts Mitochondria Dynamics in Spinocerebellar Ataxia Type 3 Models.

Spinocerebellar ataxia type 3 (SCA3), known as Machado-Joseph disease, is an autosomal dominant disease caused by an abnormal expansion of polyglutamine in ATXN3 gene, leading to neurodegeneration in SCA3 patients. Similar to other neurodegenerative diseases, the dysfunction of mitochondria is observed to cause neuronal death in SCA3 patients. Based on previous studies, proteolytic cleavage of mutant ATXN3 is found to produce truncated C-terminal fragments in SCA3 models. However, whether these truncated mutant fragments disturb mitochondrial functions and result in pathological death is still unclear. Here, we used neuroblastoma cell and transgenic mouse models to examine the effects of truncated mutant ATXN3 on mitochondria functions. In different models, we observed truncated mutant ATXN3 accelerated the formation of aggregates, which translocated into the nucleus to form intranuclear aggregates. In addition, truncated mutant ATXN3 caused more mitochondrial fission, and decreased the expression of mitochondrial fusion markers, including Mfn-1 and Mfn-2. Furthermore, truncated mutant ATXN3 decreased the mitochondrial membrane potential, increased reactive oxygen species and finally increased cell death rate. In transgenic mouse models, truncated mutant ATXN3 also led to more mitochondrial dysfunction, neurodegeneration and cell death in the cerebellums. This study supports the toxic fragment hypothesis in SCA3, and also provides evidence that truncated mutant ATXN3 is severer than full-length mutant one in vitro and in vivo.

Lentiviral transgenesis in mice via a simple method of viral concentration.

Transgenic animals are important in vivo models for biological research. However, low transgenic rates are commonly reported in the literature. Lentiviral transgenesis is a promising method that has greater efficiency with regard to generating transgenic animals, although the transgenic rate of this approach is highly dependent on different transgenes and concentrated lentiviruses. In this study, we modified a method to concentrate lentiviruses using a table centrifuge, commonly available in most laboratories, and carried out analysis of the transgenic efficiency in mice. Based on 26 individual constructs and 627 live pups, we found that the overall transgenic rate was more than 30%, which is higher than obtained with pronuclear microinjection. In addition, we did not find any significant differences in transgenic efficiency when the size of inserts was less than 5000 bp. These results not only show that our modified method can successfully generate transgenic mice but also suggest that this approach could be generally applied to different constructs when the size of inserts is less than 5000 bp. It is anticipated that the results of this study can help encourage the wider laboratory use of lentiviral transgenesis in mice.

Stem cell transplantation therapy in Parkinson's disease.

Ineffective therapeutic treatments and inadequate repair ability in the central nervous system are disturbing problems for several neurological diseases. Fortunately, the development of clinically applicable populations of stem cells has provided an avenue to overcome the failure of endogenous repair systems and substitute new cells into the damaged brain. However, there are still several existing obstacles to translating into clinical application. Here we review the stem-cell based therapies for Parkinson's disease and discuss the potential advantages and drawbacks. We hope this review may provide suggestions for viable strategies to overcome the current technical and biological issues associated with the application of stem cells in Parkinson's disease.