Intracerebral transplantation of neural stem cells combined with trehalose ingestion alleviates pathology in a mouse model of Huntington's disease

The present investigation examined the neuroprotective benefits for combined trehalose administration with C17.2 neural stem cell transplantation in a transgenic mouse model of Huntington's disease (HD), R6/2. C17.2 neural stem cells have the potential of differentiating into a neuronal phenotype in vitro and have been shown to be effective in the treatment of a variety of lysosomal lipid storage disorders in the nervous system. In this study, we transplanted these cells into the lateral ventricle of R6/2 transgenic mice in order to examine the efficacy of using these cells for correcting the accumulated polyglutamine storage materials in HD. To improve efficacy, animals were fed with a diet rich in trehalose, which has been shown to be beneficial to retard aggregate formation. The combined treatment strategy not only decreased ubiquitin-positive aggregation in striatum, alleviated polyglutamine aggregation formation, and reduced striatal volume, but also extended life span in the R6/2 animal model. Behavioral evaluation showed that the combination treatment improved motor function. Statistical analysis revealed that the combination treatment was more effective than treatment with trehalose alone on the basis of the above biochemical and behavioral criteria. This study provides a strong a basis for further developing an effective therapeutic strategy for HD.     

IGF-1 protects against diabetic features in an in vivo model of Huntington's disease

Huntington's disease (HD) is the most prevalent polyglutamine expansion disorder. HD is caused by an expansion of CAG triplet in the huntingtin (HTT) gene, associated with striatal and cortical neuronal loss. Central and peripheral metabolic abnormalities and altered insulin-like growth factor-1 (IGF-1) levels have been described in HD. Thus, we hypothesized that restoration of IGF-1-mediated signaling pathways could rescue R6/2 mice from metabolic stress and behavioral changes induced by polyglutamine expansion. We analyzed the in vivo effect of continuous peripheral IGF-1 administration on diabetic parameters, body weight and motor behavior in the hemizygous R6/2 mouse model of HD. We used 9 week-old and age-matched wild-type mice, subjected to continuously infused recombinant IGF-I or vehicle, for 14 days. IGF-1 treatment prevented the age-related decrease in body weight in R6/2 mice. Although blood glucose levels were higher in R6/2 mice, they did not reach a diabetic state. Even though, IGF-1 ameliorated poor glycemic control in HD mice. This seemed to be associated with a decrease in blood insulin levels in R6/2 mice, which was increased following IGF-1 infusion. Similarly, blood IGF-1 levels decreased during aging in both wild-type and R6/2 mice, being significantly improved upon its continuous infusion. Although no significant differences were found in motor function in R6/2-treated mice, IGF-1 treatment highly improved paw clasping scores. In summary, these results suggest that IGF-1 has a protective role against HD-associated impaired glucose tolerance, by enhancing blood insulin levels.     

Heat shock proteins in the retina: Focus on HSP70 and alpha crystallins in ganglion cell survival

Heat shock proteins (HSPs) belong to a superfamily of stress proteins that are critical constituents of a complex defense mechanism that enhances cell survival under adverse environmental conditions. Cell protective roles of HSPs are related to their chaperone functions, antiapoptotic and antinecrotic effects. HSPs' anti-apoptotic and cytoprotective characteristics, their ability to protect cells from a variety of stressful stimuli, and the possibility of their pharmacological induction in cells under pathological stress make these proteins an attractive therapeutic target for various neurodegenerative diseases; these include Alzheimer's, Parkinson's, Huntington's, prion disease, and others. This review discusses the possible roles of HSPs, particularly HSP70 and small HSPs (alpha A and alpha B crystallins) in enhancing the survival of retinal ganglion cells (RGCs) in optic neuropathies such as glaucoma, which is characterized by progressive loss of vision caused by degeneration of RGCs and their axons in the optic nerve. Studies in animal models of RGC degeneration induced by ocular hypertension, optic nerve crush and axotomy show that upregulation of HSP70 expression by hyperthermia, zinc, geranyl–geranyl acetone, 17-AAG (a HSP90 inhibitor), or through transfection of retinal cells with AAV2-HSP70 effectively supports the survival of injured RGCs. RGCs survival was also stimulated by overexpression of alpha A and alpha B crystallins. These findings provide support for translating the HSP70- and alpha crystallin-based cell survival strategy into therapy to protect and rescue injured RGCs from degeneration associated with glaucomatous and other optic neuropathies.     

Effects of Schisandra chinensis Baillon (Schizandraceae) on lipopolysaccharide induced lung inflammation in mice

Aim of the study

This study was aimed to evaluate the neuroprotective and anti-aging activity of extracts in Caenorhabditis elegans from the roots and leaves of Damnacanthus officinarum Huang to provide the pharmacological basis in traditional medicine.

Materials and methods

Investigations on the neuroprotective and lifespan activity were carried out, which were observed by utilizing the following models: observing the worms’ chemosensory behavior test based on the aversion index in the assay plate, neuroprotective activity of nematode by evaluating the ASH neuron survival and lifespan test in C. elegans.

Results

It has been shown that the ethanol, n-butanol and aqueous extracts in the roots possessed significantly neuroprotective effect both in chemosensory behavior test and ASH neuron survival model. The same extracts in the leaves showed similar activities in two models, but have less potency revealing by the data. Four candidate extracts, possessing excellent neuroprotective activity, extend lifespan in C. elegans. The n-butanol extracts in the root part showed best efficacy among them.

Conclusion

The results show the n-butanol and aqueous extracts are the major pharmacological plant extracts. Moreover, the neuroprotective and lifespan-extension activity effects of root extracts are superior to leave extracts, supporting the traditional application of above-ground parts of DOH in treating various diseases associated with brain disorders and anti-aging.     

Pathological accumulation of atrophin-1 in dentatorubralpallidoluysian atrophy

Dentatorubral-pallidoluysian atrophy (DRPLA) is caused by the expansion of polyglutamine (polyQ) in atrophin-1 (ATN1), also known as DRPLA protein. ATN1 is ubiquitously expressed in the central nervous system (CNS), although selective regions of CNS are degenerated in DRPLA, and this selective neuronal damage gives rise to the specific clinical features of DRPLA. Accumulation of mutant ATN1 that carries an expanded polyQ tract seems to be the primary cause of DRPLA neurodegeneration, but it is still unclear how the accumulation of ATN1 leads to neu-rodegeneration. Recently, cleaved fragments of ATN1 were shown to accumulate in the disease models and the brain tissues of patients with DRPLA. Furthermore, proteolytic processing of ATN1 may regulate the intracellular localization of ATN1 and its fragments. Therefore, proteolytic processing of ATN1 may provide clues to disease pathogenesis and hopefully aid in the determination of molecular targets for effective therapeutic approaches for DRPLA.     

Evidence for sequestration of polyglutamine inclusions by Drosophila myeloid leukemia factor

Intracellular inclusions of abnormally long polyglutamine tracts and neurotoxicity are the hallmarks of several hereditary neurodegenerative disorders, including Huntington's disease (HD). In Drosophila melanogaster, dMLF, an ortholog of human myeloid leukemia factors, hMLF1 and hMLF2, suppressed polyglutamine toxicity and colocalized with the inclusions. In transfected primary rat neuronal cultures, dMLF and its orthologs reduced the morphological phenotypes and inclusions. Furthermore, dMLF reduced the recruitment of CBP and Hsp70 into the inclusions, both of which are among many essential proteins apparently trapped in the inclusions. These data suggest that a possible mechanism of suppression by dMLF is via the sequestration of polyglutamine oligomers or inclusions.     

Impaired ERAD and ER stress are early and specific events in polyglutamine toxicity

Protein misfolding, whether caused by aging, environmental factors, or genetic mutations, is a common basis for neurodegenerative diseases. The misfolding of proteins with abnormally long polyglutamine (polyQ) expansions causes several neurodegenerative disorders, such as Huntington’s disease (HD). Although many cellular pathways have been documented to be impaired in HD, the primary triggers of polyQ toxicity remain elusive. We report that yeast cells and neuron-like PC12 cells expressing polyQ-expanded huntingtin (htt) fragments display a surprisingly specific, immediate, and drastic defect in endoplasmic reticulum (ER)-associated degradation (ERAD). We further decipher the mechanistic basis for this defect in ERAD: the entrapment of the essential ERAD proteins Npl4, Ufd1, and p97 by polyQ-expanded htt fragments. In both yeast and mammalian neuron-like cells, overexpression of Npl4 and Ufd1 ameliorates polyQ toxicity. Our results establish that impaired ER protein homeostasis is a broad and highly conserved contributor to polyQ toxicity in yeast, in PC12 cells, and, importantly, in striatal cells expressing full-length polyQ-expanded huntingtin.     

Ataxin-2 intermediate-length polyglutamine: a possible risk factor for Chinese patients with amyotrophic lateral sclerosis

Intermediate-length polyglutamine (polyQ) expansions in the ataxin-2 (ATXN2) gene have recently been identified as a risk factor for sporadic amyotrophic lateral sclerosis (SALS). Our study aims to analyze cytosine, adenine, guanine (CAG)n expansions in the ATXN2 gene among Chinese patients with SALS. All patients diagnosed with adult-onset sporadic amyotrophic lateral sclerosis (ALS) were consecutively followed up, and their clinical characteristics were collected. To measure the repeat length of ATXN2 polyQ, fluorescence-polymerase chain reaction products were analyzed on a 3100-Avant Genetic Analyzer Applied Biosystem (Foster City, CA, USA) using the ROC-500 size standard. Three hundred forty-five patients with SALS were studied. The mean age of onset was 51.38 ± 12.45 years. ATXN2 polyQ with a repeat length greater than 27 was found to be weakly associated with amyotrophic lateral sclerosis in our study. There was no significant difference in mean age of onset, gender, and onset site between the group of SALS patients with and without ATXN2 polyQ expansion greater than 27. Our finding provides evidence that the ATXN2 polyQ expansion greater than 27 might be a risk factor for Chinese SALS patients.     

Engineered antibody therapies to counteract mutant huntingtin and related toxic intracellular proteins

The engineered antibody approach to Huntington's disease (HD) therapeutics is based on the premise that significantly lowering the levels of the primary misfolded mutant protein will reduce abnormal protein interactions and direct toxic effects of the misfolded huntingtin (HTT). This will in turn reduce the pathologic stress on cells, and normalize intrinsic proteostasis. Intracellular antibodies (intrabodies) are single-chain (scFv) and single-domain (dAb; nanobody) variable fragments that can retain the affinity and specificity of full-length antibodies, but can be selected and engineered as genes. Functionally, they represent a protein-based approach to the problem of aberrant mutant protein folding, post-translational modifications, protein-protein interactions, and aggregation. Several intrabodies that bind on either side of the expanded polyglutamine tract of mutant HTT have been reported to improve the mutant phenotype in cell and organotypic cultures, fruit flies, and mice. Further refinements to the difficult challenges of intraneuronal delivery, cytoplasmic folding, and long-term efficacy are in progress. This review covers published studies and emerging approaches on the choice of targets, selection and engineering methods, gene and protein delivery options, and testing of candidates in cell and animal models. The resultant antibody fragments can be used as direct therapeutics and as target validation/drug discovery tools for HD, while the technology is also applicable to a wide range of neurodegenerative and other diseases that are triggered by toxic proteins.