Alterations in Leptin Signaling in Amyotrophic Lateral Sclerosis (ALS).

Leptin has been suggested to play a role in amyotrophic lateral sclerosis (ALS), a fatal progressive neurodegenerative disease. This adipokine has previously been shown to be associated with a lower risk of ALS and to confer a survival advantage in ALS patients. However, the role of leptin in the progression of ALS is unknown. Indeed, our understanding of the mechanisms underlying leptin's effects in the pathogenesis of ALS is very limited, and it is fundamental to determine whether alterations in leptin's actions take place in this neurodegenerative disease. To characterize the association between leptin signaling and the clinical course of ALS, we assessed the mRNA and protein expression profiles of leptin, the long-form of the leptin receptor (Ob-Rb), and leptin-related signaling pathways at two different stages of the disease (onset and end-stage) in TDP-43A315T mice compared to age-matched WT littermates. In addition, at selected time-points, an immunoassay analysis was conducted to characterize plasma levels of total ghrelin, the adipokines resistin and leptin, and metabolic proteins (plasminogen activator inhibitor type 1 (PAI-1), gastric inhibitory peptide (GIP), glucagon-like peptide 1 (GLP-1), insulin and glucagon) in TDP-43A315T mice compared to WT controls. Our results indicate alterations in leptin signaling in the spinal cord and the hypothalamus on the backdrop of TDP-43-induced deficits in mice, providing new evidence about the pathways that could link leptin signaling to ALS.

Alterations to metabolic hormones in amyotrophic lateral sclerosis and frontotemporal dementia postmortem human tissue.

Metabolic changes are observed in patients with both amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Although regulation of metabolic processes in the CNS is predominantly carried out within the hypothalamus, extra-hypothalamic CNS areas contain metabolic hormone receptors, including those for leptin (LEPR), insulin (INSR), and neuropeptide Y (NPY), indicating that they may play a role in biological processes underlying pathogenic disease processes. The status of these hormones within regions vulnerable in ALS/FTD is not well described. This study sought to determine whether the expression of these hormones and their receptors is altered in pathology-rich regions in cases of human FTD (superior frontal gyrus and insular cortex) and ALS (primary motor cortex and lumbar spinal cord) with TDP-43 pathology compared to matched healthy controls. LEPR mRNA was increased within the superior frontal gyrus of FTD cases and within primary motor cortex and lumbar spinal cord of ALS cases; INSR mRNA was increased in superior frontal gyrus and insular cortex of FTD cases. NPY protein was decreased in primary motor cortex and lumbar spinal cord of ALS cases. Our results demonstrate that metabolic hormones undergo complex alterations in ALS and FTD and suggest that these hormones could play critical roles in the pathogenesis of these diseases.

The potential benefit of leptin therapy against amyotrophic lateral sclerosis (ALS).

BACKGROUND: Targeting leptin could represent a rational strategy to treat amyotrophic lateral sclerosis (ALS), as previously clinical studies have shown its levels to be associated with a lower risk of ALS disease. However, very little is known about the potential influence of leptin in altering disease progression in ALS, as it has thus far been correlated with the protection exerted by increased fat mass stores. METHODS: We studied the impact of leptin treatment beginning at 42-days of age (asymptomatic stage of disease) in the TDP-43 (TDP43A315T ) transgenic (Tg) ALS mouse model. RESULTS: Our study shows that leptin treatment was associated with altered expression of adipokines and metabolic proteins in TDP43A315T mice. We also observed that weight loss decline was less prominent after leptin treatment in TDP43A315T mice relative to vehicle-treated animals. In TDP43A315T mice treated with leptin the disease duration lasted longer along with an improvement in motor performance relative to vehicle-treated animals. CONCLUSIONS: Collectively, our results support leptin as a potential novel treatment approach for ALS.

Ozone modified hypothalamic signaling enhancing thermogenesis in the TDP-43A315T transgenic model of Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS), a devastating progressive neurodegenerative disease, has no effective treatment. Recent evidence supports a strong metabolic component in ALS pathogenesis. Indeed, metabolic abnormalities in ALS correlate to disease susceptibility and progression, raising additional therapeutic targets against ALS. Ozone (O3), a natural bioactive molecule, has been shown to elicit beneficial effects to reduce metabolic disturbances and improved motor behavior in TDP-43A315T mice. However, it is fundamental to determine the mechanism through which O3 acts in ALS. To characterize the association between O3 exposure and disease-associated weight loss in ALS, we assessed the mRNA and protein expression profile of molecular pathways with a main role in the regulation of the metabolic homeostasis on the hypothalamus and the brown adipose tissue (BAT) at the disease end-stage, in TDP-43A315T mice compared to age-matched WT littermates. In addition, the impact of O3 exposure on the faecal bacterial community diversity, by Illumina sequencing, and on the neuromuscular junctions (NMJs), by confocal imaging, were analysed. Our findings suggest the effectiveness of O3 exposure to induce metabolic effects in the hypothalamus and BAT of TDP-43A315T mice and could be a new complementary non-pharmacological approach for ALS therapy.

Design of Mesoporous Silica Nanoparticles for the Treatment of Amyotrophic Lateral Sclerosis (ALS) with a Therapeutic Cocktail Based on Leptin and Pioglitazone.

Amyotrophic lateral sclerosis (ALS) is a devasting neurodegenerative disease with no cure to date. Therapeutic agents used to treat ALS are very limited, although combined therapies may offer a more effective treatment strategy. Herein, we have studied the potential of nanomedicine to prepare a single platform based on mesoporous silica nanoparticles (MSNs) for the treatment of an ALS animal model with a cocktail of agents such as leptin (neuroprotective) and pioglitazone (anti-inflammatory), which have already demonstrated promising therapeutic ability in other neurodegenerative diseases. Our goal is to study the potential of functionalized mesoporous materials as therapeutic agents against ALS using MSNs as nanocarriers for the proposed drug cocktail leptin/pioglitazone (MSN-LEP-PIO). The nanostructured materials have been characterized by different techniques, which confirmed the incorporation of both agents in the nanosystem. Subsequently, the effect, in vivo, of the proposed drug cocktail, MSN-LEP-PIO, was used in the murine model of TDP-43 proteinopathy (TDP-43A315T mice). Body weight loss was studied, and using the rotarod test, motor performance was assessed, observing a continuous reduction in body weight and motor coordination in TDP-43A315T mice and wild-type (WT) mice. Nevertheless, the disease progression was slower and showed significant improvements in motor performance, indicating that TDP-43A315T mice treated with MSN-LEP-PIO seem to have less energy demand in the late stage of the symptoms of ALS. Collectively, these results seem to indicate the efficiency of the systems in vivo and the usefulness of their use in neurodegenerative models, including ALS.

Cancer mortality inequalities in urban areas: a Bayesian small area analysis in Spanish cities.

BACKGROUND: Intra-urban inequalities in mortality have been infrequently analysed in European contexts. The aim of the present study was to analyse patterns of cancer mortality and their relationship with socioeconomic deprivation in small areas in 11 Spanish cities. METHODS: It is a cross-sectional ecological design using mortality data (years 1996-2003). Units of analysis were the census tracts. A deprivation index was calculated for each census tract. In order to control the variability in estimating the risk of dying we used Bayesian models. We present the RR of the census tract with the highest deprivation vs. the census tract with the lowest deprivation. RESULTS: In the case of men, socioeconomic inequalities are observed in total cancer mortality in all cities, except in Castellon, Cordoba and Vigo, while Barcelona (RR = 1.53 95%CI 1.42-1.67), Madrid (RR = 1.57 95%CI 1.49-1.65) and Seville (RR = 1.53 95%CI 1.36-1.74) present the greatest inequalities. In general Barcelona and Madrid, present inequalities for most types of cancer. Among women for total cancer mortality, inequalities have only been found in Barcelona and Zaragoza. The excess number of cancer deaths due to socioeconomic deprivation was 16,413 for men and 1,142 for women. CONCLUSION: This study has analysed inequalities in cancer mortality in small areas of cities in Spain, not only relating this mortality with socioeconomic deprivation, but also calculating the excess mortality which may be attributed to such deprivation. This knowledge is particularly useful to determine which geographical areas in each city need intersectorial policies in order to promote a healthy environment.

Methodology Aspects of Colony Maintain for a Murine Model of Amyotrophic Lateral Sclerosis (ALS) TDP-43 Proteinopathy.

The use of genetically engineered mouse (GEMs) models provides an unprecedented opportunity to study the genetic basis of diseases and gene function, therefore it is paramount to determine reproductive parameters that guarantee proper colony maintenance. We studied the reproductive parameters of mice hemizygous for TDP-43A315T transgene, which are viable, fertile, and express a mutant human TAR DNA binding protein (hTDP-43) cDNA harboring an amino acid substitution associated with familial amyotrophic lateral sclerosis (fALS). TDP43A315T mice were backcrossed to a C57Bl6/J pure background for four consecutive generations. The Tg offspring genotype were then confirmed by PCR assays. Our statistical analysis indicated there were no differences in the sex and number of pups per offspring when hemizygous female and male TDP43A315T mice were backcrossed to C57Bl6/J mice. Interestingly, our results showed significant differences in the number of offspring expressing the transgene when hemizygous TDP43A315T male mice were used as breeders. Therefore, our findings suggest that male TDP43A315T mice transfer the transgene with a greater genetic strengths. Such is an important breeding consideration to ensure the principle of reduction in animal experimentation considering most basic research with models focuses on males and excludes female mice.

Enhanced Anti-Amyloid Effect of Combined Leptin and Pioglitazone in APP/PS1 Transgenic Mice.

BACKGROUND: Alzheimer's disease (AD) has challenged single-target therapeutic strategies, raising the possibility that combined therapies may offer a more effective treatment strategy. OBJECTIVE: There is substantial evidence for the efficacy of leptin (L) (neuroprotective hormone) and pioglitazone (P) (anti-inflammatory agent) as monotherapies in AD. We have previously shown that combination treatment of L+P in APP/PS1 mice at the onset of pathology significantly improved memory and reduced brain Aß levels relative to control mice. In this new study, we sought to replicate our previous findings in a new cohort of APP/PS1 mice to further confirm whether the combined treatment of L+P is superior to each treatment individually. METHODS: We have re-evaluated the effects of L+P co-treatment in APP/PS1 mice using thioflavin-S staining, MOAß immunolabeling, and enzyme-linked immunosorbent assay (ELISA) to examine effects on Aß levels and pathology, relative to animals that received L or P individually. RESULTS: We demonstrated that a combination of L and P significantly enhances the anti-Aß effect of L or P in the hippocampus of APP/PS1 mice. CONCLUSION: Our findings suggest that combining L and P significantly enhances the anti-Aß effect of L or P in the hippocampus of APP/PS1 mice and maybe a potential new effective strategy for AD therapy.

Central s-resistin deficiency ameliorates hypothalamic inflammation and increases whole body insulin sensitivity.

S-resistin, a non-secretable resistin isoform, acts as an intracrine factor that regulates adipocyte maduration, inflammatory and insulin response in 3T3-L1 cells. However, its intracellular function in vivo is still unknown. In this study, we analyze the central role of s-resistin, decreasing its hypothalamic expression using an intracerebroventricular injection of lentiviral RNAi. The data present herein support an improvement in the hypothalamic leptin and insulin signaling pathway upon s-resistin downregulation. Furthermore, hypothalamic levels of pro-inflammatory markers decrease, meanwhile those of the anti-inflammatory cytokine IL-10 increases. Interestingly, peripheral NEFA decreases alike circulating leptin and resistin levels. These data demonstrate that hypothalamic s-resistin controls fuel mobilization and adipokines secretion. Importantly, central s-resistin downregulation improves systemic insulin sensitivity, as demonstrated after an IPGTT. Interestingly, our data also indicate that s-resistin downregulation could improve hypothalamic inflammation in aged Wistar rats. Altogether, our findings suggest that hypothalamic s-resistin seems to be a key regulator of the brain-fat axis which links inflammation with metabolic homeostasis.

Combination treatment with leptin and pioglitazone in a mouse model of Alzheimer's disease.

INTRODUCTION: Combination therapy approaches may be necessary to address the many facets of pathologic change in the brain in Alzheimer's disease (AD). The drugs leptin and pioglitazone have previously been shown individually to have neuroprotective and anti-inflammatory actions, respectively, in animal models. METHODS: We studied the impact of combined leptin and pioglitazone treatment in 6-month-old APP/PS1 (APPswe/PSEN1dE9) transgenic AD mouse model. RESULTS: We report that an acute 2-week treatment with combined leptin and pioglitazone resulted in a reduction of spatial memory deficits (Y maze) and brain ß-amyloid levels (soluble ß-amyloid and amyloid plaque burden) relative to vehicle-treated animals. Combination treatment was also associated with amelioration in plaque-associated neuritic pathology and synapse loss, and also a significantly reduced neocortical glial response. DISCUSSION: Combination therapy with leptin and pioglitazone ameliorates pathologic changes in APP/PS1 mice and may represent a potential treatment approach for AD.

Environmental novelty exacerbates stress hormones and Aß pathology in an Alzheimer's model.

Cognitive stimulation has been proposed as a non-pharmacological intervention to be used in primary, secondary and tertiary prevention approaches for Alzheimer's disease. A common familial Alzheimer's disease transgenic model showed heightened levels of the stress hormone, corticosterone. When exposed to periodic enhanced cognitive stimulation, these animals demonstrated further heightened levels of corticosterone as well as increased Aß pathology. Hence, Alzheimer's disease may be associated with hypothalamic-pituitary-adrenal (HPA) axis dysfunction, causing stimulatory environments to become stress-inducing, leading to a glucocorticoid-pathology cycle contributing to further Aß release and plaque formation. This finding suggests that stimulation-based interventions and local environments for people with Alzheimer's disease need to be designed to minimise a stress response that may exacerbate brain pathology.

Mid-life environmental enrichment increases synaptic density in CA1 in a mouse model of Aß-associated pathology and positively influences synaptic and cognitive health in healthy ageing.

Early-life cognitive enrichment may reduce the risk of experiencing cognitive deterioration and dementia in later-life. However, an intervention to prevent or delay dementia is likely to be taken up in mid to later-life. Hence, we investigated the effects of environmental enrichment in wildtype mice and in a mouse model of Aß neuropathology (APPSWE /PS1dE9 ) from 6 months of age. After 6 months of housing in standard laboratory cages, APPSWE /PS1dE9 (n = 27) and healthy wildtype (n = 21) mice were randomly assigned to either enriched or standard housing. At 12 months of age, wildtype mice showed altered synaptic protein levels and relatively superior cognitive performance afforded by environmental enrichment. Environmental enrichment was not associated with alterations to Aß plaque pathology in the neocortex or hippocampus of APPSWE /PS1dE9 mice. However, a significant increase in synaptophysin immunolabeled puncta in the hippocampal subregion, CA1, in APPSWE /PS1dE9 mice was detected, with no significant synaptic density changes observed in CA3, or the Fr2 region of the prefrontal cortex. Moreover, a significant increase in hippocampal BDNF was detected in APPSWE /PS1dE9 mice exposed to EE, however, no changes were detected in neocortex or between Wt animals. These results demonstrate that mid to later-life cognitive enrichment has the potential to promote synaptic and cognitive health in ageing, and to enhance compensatory capacity for synaptic connectivity in pathological ageing associated with Aß deposition.

Erratum: C9ORF72 expression and cellular localization over mouse development.

After publication of this article it was noticed there was an error in the Methods section under the subsection: Protein extraction and western blot analysis. The text including the error is as follows: "Denatured protein samples (15 µg) from each time-point were electrophoresed into 10 % SDS-PAGE gels (BioRad), transferred to PVDF membranes (BioRad) and incubated in primary antibodies overnight (Table 1)". Instead it should read: "…antibodies, C9ORF72 (1:500, Santa Cruz, sc-138763) and GAPDH (1:7000, Millipore), overnight." This error has since been updated in the article.

Defining the earliest pathological changes of Alzheimer's disease.

The prospects for effectively treating well-established dementia, such as Alzheimer's disease (AD), are slim, due to the destruction of key brain pathways that underlie higher cognitive function. There has been a substantial shift in the field towards detecting conditions such as AD in their earliest stages, which would allow preventative or therapeutic approaches to substantially reduce risk and/or slow the progression of disease. AD is characterized by hallmark pathological changes such as extracellular Aß plaques and intracellular neurofibrillary pathology, which selectively affect specific subclasses of neurons and brain circuits. Current evidence indicates that Aß plaques begin to form many years before overt dementia, a gradual and progressive pathology which offers a potential target for early intervention. Early Aß changes in the brain result in localized damage to dendrites, axonal processes and synapses, to which excitatory synapses and the processes of projection neurons are highly vulnerable. Aß pathology is replicated in a range of transgenic models overexpressing mutant human familial AD genes (e.g. APP and presenilin 1). Studying the development of aberrant regenerative and degenerative changes in neuritic processes associated with Aß plaques may represent the best opportunity to understand the relationship between the pathological hallmarks of AD and neuronal damage, and to develop early interventions to prevent, slow down or mitigate against Aß pathology and/or the neuronal alterations that leads to cognitive impairment.

Neurofilament light gene deletion exacerbates amyloid, dystrophic neurite, and synaptic pathology in the APP/PS1 transgenic model of Alzheimer's disease.

Alzheimer's disease (AD) is a progressive neurodegenerative disease associated with the loss of cognitive function. Neurofilament (NF) triplet proteins, the major structural (intermediate filament) proteins of neurons, are expressed in a subset of pyramidal cells that show a high degree of vulnerability to degeneration in AD. Alterations in the NF triplet proteins in amyloid-beta (Aß) plaque-associated dystrophic neurites (DNs) represent the first cytoskeletal aberration to occur in the neocortex in the earliest stages of AD. We generated transgenic APP/PS1 (APPswe/PSEN1dE9) mice on the neurofilament light knockout (NFL KO) background to explore the role of NFL deletion in the context of DN formation, synaptic changes, and other neuropathologic features. Our analysis demonstrated that NFL deficiency significantly increased neocortical DN pathology, Aß deposition, synapse vulnerability, and microgliosis in APP/PS1 mice. Thus, NFs may have a role in protecting neurites from dystrophy and in regulating cellular pathways related to the generation of Aß plaques.

Changes in TDP-43 expression in development, aging, and in the neurofilament light protein knockout mouse.

The transactive response DNA-binding protein 43 (TDP-43) has been identified as a neurofilament light (NF-L) messenger RNA (mRNA)-binding protein. Abnormally increased levels of TDP-43 are detected in patients with amyotrophic lateral sclerosis and a downregulation of NF-L mRNA. However, links between NF-L and TDP-43 expressions are unclear. In this study, we investigated whether the deficiency of NF-L protein can result in alterations in TDP-43 localization or protein expression and whether this is altered with aging. There was a significant increase in TDP-43 protein levels in the cortex and lumbar spinal cord in 12-month-old NF-L knockout (NF-L KO) mice, compared with wild-type (WT) C57BL/6 mice. However, there was no difference in either the phosphorylation of TDP-43 between WT and NF-L KO mice or the abnormal mislocalization of TDP-43 to the cytoplasm in NF-L KO animals. Our findings suggest that NF-L protein or mRNA may negatively affect the expression of TDP-43 in the central nervous system. However, altered phosphorylation of TDP-43 may be more highly associated with aging than the levels of TDP-43 expression.

C9ORF72 expression and cellular localization over mouse development.

INTRODUCTION: A majority of familial frontotemporal lobar dementia and amyotrophic lateral sclerosis cases are associated with a large repeat expansion in a non-coding region of the C9ORF72 gene. Currently, little is known about the normal function and the expression pattern of the C9ORF72 protein. The aims of this study were to characterize the expression pattern and cellular localization of the three reported mouse isoforms of C9orf72, over a developmental time-course in primary cultured cortical neurons and brain tissue from C57BL/6 mice. RESULTS: We demonstrated that the different isoforms of C9ORF72 at the mRNA and protein level undergo alterations in expression during development and into adulthood. Cellular fractionation and immunofluorescence demonstrated that levels of nuclear and cytoplasmic expression of isoforms changed significantly over the time course. Additionally, immunofluorescence studies showed C9ORF72 labeling as puncta throughout neurons, extending beyond the microtubule cytoskeleton into actin-rich structures such as filopodia and growth cones. Finally, synaptosome preparations demonstrated the presence of C9ORF72 isoform 1 in synaptic-rich fractions from adult mouse brain. CONCLUSION: In summary, the presence of C9ORF72 as puncta and within synaptic-rich fractions may indicate involvement at the synapse and differential expression of isoforms in nuclei and cytoplasm may suggest distinct roles for the isoforms. Determining the physiological role of C9ORF72 protein may help to determine the role it plays in disease.