•Morphology of Agave salmiana.•Geographical distribution of agaves.•Population studies of agave.
Agave salmiana represents a high economic and cultural relevance in Mexican society. Cultivated in ...arid zones of Mexico, it is the agave species primarily used for the production of mezcal, a traditional Mexican alcoholic beverage. In this study, we performed a morphological comparison among 145 accessions of Agave salmiana ssp. crassispina and ssp. salmiana from 14 municipalities in northern Guanajuato. A total of 12 morphological variables of leaf size, spines and teeth were measured. In order to perform this evaluation, agave plants were considered either as cultivated or wild-type. Statistical analyzes were conducted and a dendrogram was constructed with the nearest neighbor method, analysis of variance (ANOVA) and Fisher’s Least Significant Difference (LSD) multiple comparisons. Several groups were established within the dendrogram and the distance among the groups was found to be small. The ANOVA shows significant differences among the subspecies and the populations, whereas the multiple comparisons detected several groups. The statistical analyses showed a morphological variation among the studied plants. However, the whole population under study falls within a range of morphological homogeneity.
Cellular responses in the V2 secondary visual cortex to simple as well as complex visual stimuli have been well studied. However, the role of area V2 in visual memory remains unexplored. We found ...that layer 6 neurons of V2 are crucial for the processing of object-recognition memory (ORM). Using the protein regulator of G protein signaling-14 (RGS-14) as a tool, we found that the expression of this protein into layer 6 neurons of rat-brain area V2 promoted the conversion of a normal short-term ORM that normally lasts for 45 minutes into long-term memory detectable even after many months. Furthermore, elimination of the same-layer neurons by means of injection of a selective cytotoxin resulted in the complete loss of normal as well as protein-mediated enhanced ORM.
Display omitted
•This is the first report of a lipolytic enzyme identified in vivo in papaya.•CpLIP2 was successfully cloned and functionally expressed in N. benthamiana.•CpLIP2 has a preference for ...short-chain triglycerides as papaya latex.
Plants are a very interesting and new source of lipases for a variety of applications. Carica papaya is a remarkable source of lipases, as its genome reveals several putative lipolytic genes whose expression, function and applications remain undefined. In this study, total RNA from papaya leaves was isolated and used as a template to amplify the open reading frame (ORF) of a putative GDSL lipase gene, CpLIP2, by RT-PCR. It was found that CpLIP2 expression is induced by inoculation of papaya plants with the fungal pathogen Corynespora cassiicola. The CpLIP2 ORF was further cloned into a viral provector module for transient expression in Nicotiana benthamiana plants. The presence of CpLIP2 transcripts in CpLIP2-transformed plants was demonstrated by RT-PCR. Importantly, lipase activity was only detected in extracts from plants transformed with the CpLIP2 gene and not in those from plants transformed with an irrelevant gene used as a negative control, confirming that the gene was successfully expressed and that its product retained activity. A characterization of substrate specificity showed that CpLIP2 has a preference for short-chain rather than medium- and long-chain triglycerides.
Neurotrophins, activating the PI3K/Akt signaling pathway, control neuronal survival and plasticity. Alterations in NGF, BDNF, IGF-1, or insulin signaling are implicated in the pathogenesis of ...Alzheimer disease. We have previously characterized a bigenic PS1×APP transgenic mouse displaying early hippocampal Aβ deposition (3 to 4 months) but late (17 to 18 months) neurodegeneration of pyramidal cells, paralleled to the accumulation of soluble Aβ oligomers. We hypothesized that PI3K/Akt/GSK-3β signaling pathway could be involved in this apparent age-dependent neuroprotective/neurodegenerative status. In fact, our data demonstrated that, as compared with age-matched nontransgenic controls, the Ser-9 phosphorylation of GSK-3β was increased in the 6-month PS1×APP hippocampus, whereas in aged PS1×APP animals (18 months), GSK-3β phosphorylation levels displayed a marked decrease. Using N2a and primary neuronal cell cultures, we demonstrated that soluble amyloid precursor protein-α (sAPPα), the predominant APP-derived fragment in young PS1×APP mice, acting through IGF-1 and/or insulin receptors, activated the PI3K/Akt pathway, phosphorylated the GSK-3β activity, and in consequence, exerted a neuroprotective action. On the contrary, several oligomeric Aβ forms, present in the soluble fractions of aged PS1×APP mice, inhibited the induced phosphorylation of Akt/GSK-3β and decreased the neuronal survival. Furthermore, synthetic Aβ oligomers blocked the effect mediated by different neurotrophins (NGF, BDNF, insulin, and IGF-1) and sAPPα, displaying high selectivity for NGF. In conclusion, the age-dependent appearance of APP-derived soluble factors modulated the PI3K/Akt/GSK-3β signaling pathway through the major neurotrophin receptors. sAPPα stimulated and Aβ oligomers blocked the prosurvival signaling. Our data might provide insights into the selective vulnerability of specific neuronal groups in Alzheimer disease.
Abstract
Background
Microglia, the brain‐resident myeloid cells, play a major role in the immune responses of the nervous system and in the pathogenesis of Alzheimer’s disease (AD). However, the ...presence of peripheral myeloid cells in the AD brains, and their contribution to disease progression, remain to be demonstrated.
Method
Cellular (immunostainings and image analysis) and molecular (qPCR and western blots) approaches have been carried out in post‐mortem hippocampal samples from patients with AD (Braak V‐VI) and age‐matched controls without neurological symptoms (Braak II).
Results
Our study provides evidence that circulating monocytes infiltrate the AD brains. Our findings showed that a high proportion of demented individuals was associated with up‐regulation of genes rarely expressed by microglial cells and abundant in monocytes‐derived cells (MDC), among which stands the scavenger receptor Cd163. These Cd163‐positive MDC invaded the brain parenchyma, acquired a microglial‐like morphology, and were located in close proximity to blood vessels. These cells infiltrated the nearby amyloid plaques contributing to plaque‐associated myeloid cell heterogeneity. Besides, control individuals with high amyloid pathology, showed no signs of MDC brain infiltration or plaque invasion. The MDC infiltration was associated with the progression and severity of AD pathology.
Conclusion
These results reveal the co‐existence of distinct myeloid populations associated with amyloid plaques during disease progression, as well their region‐specific contribution to neuroimmune protection. The recruitment of monocytes could be a consequence rather than the cause of the severity of the disease. Whether monocyte infiltration is beneficial or detrimental to AD pathology remains to be fully elucidated. These findings open the opportunity to design targeted therapies, not only to microglia, but also to peripheral immune cell population to modulate amyloid pathology and provide a better understanding of the immunological mechanisms underlying AD progression.
Supported by ISCiii grants(PI21‐0915 (to AG),PI21‐00914 (to JV) co‐financed by FEDER funds from European Union, by Junta de Andalucia grants P18‐RT‐2233 (to AG) and US‐1262734 (to JV) co‐financed by Programa Operativo FEDER 2014‐2020, and by grant PPIT.UMA.B1‐2019‐07 (to ESM).
Abstract
Background
Alzheimer’s disease (AD) is characterized by presenting a complex pathology, not fully resolved yet. This fact, together with the lack of reliable models, has impeded the ...development of effective therapies. Recently, several studies have shown that functional glial cell defects have a key role in the pathology of AD. However, this glial dysfunction, currently, cannot be correctly modeled using the available animal models, so we hypothesized that cells derived from Alzheimer’s patients can serve as a better platform for studying the disease. In this sense, human pluripotent stem cells (hPSC) allow the generation of different types of neural cells, which can be used for disease modeling, identification of new targets and drugs development.
Method
We have a collection of hiPSCs derived from patients with sporadic forms of AD stratified based on APOE genotype. We have differentiated these cells towards neural cells and mature them to neurons or astrocytes using a serum‐free approach, to assess intrinsic differences between those derived from AD patients or healthy controls.
Result
We have implemented a serum‐free approach and generated neural precursors and astrocytes from all the lines tested. We observe differences at the phenotypic level and a reduced capacity to differentiate towards neural lineage in those lines derived from APOE4 carriers.
Conclusion
Our preliminary data suggest intrinsic differences in the neural differentiation capacity between cell lines derived from APOE4 or APOE3 carrier subjects. Further experiments would contribute to elucidate novel pathogenic pathways associated with neurodegeneration and susceptible of therapeutic modulation, likely contributing to the development of new effective drugs against AD.
Acknowledgments: This study was supported by Instituto de Salud Carlos III (ISCiii) of Spain, co‐financed by FEDER funds from European Union, through grants PI21/00915 (to AG) and PI21/00914 (to JV); by Junta de Andalucia through Consejería de Economía y Conocimiento grants UMA20‐FEDERJA‐048 (to JAGL), PY18‐RT‐2233 (to AG) and US‐1262734 (to JV) co‐financed by Programa Operativo FEDER 2014‐2020, University of Malaga (B1‐2020_04) to JAGL and Programa Operativo de Empleo Juvenil SNGJ4‐11 to LCP.
Misfolded Aβ is involved in the progression of Alzheimer's disease (AD). However, the role of its polymorphic variants or conformational strains in AD pathogenesis is not fully understood. Here, we ...study the seeding properties of two structurally defined synthetic misfolded Aβ strains (termed 2F and 3F) using in vitro and in vivo assays. We show that 2F and 3F strains differ in their biochemical properties, including resistance to proteolysis, binding to strain‐specific dyes, and in vitro seeding. Injection of these strains into a transgenic mouse model produces different pathological features, namely different rates of aggregation, formation of different plaque types, tropism to specific brain regions, differential recruitment of Aβ40/Aβ42 peptides, and induction of microglial and astroglial responses. Importantly, the aggregates induced by 2F and 3F are structurally different as determined by ssNMR. Our study analyzes the biological properties of purified Aβ polymorphs that have been characterized at the atomic resolution level and provides relevant information on the pathological significance of misfolded Aβ strains.
Synopsis
Two structurally defined Aβ conformational variants differ in their biochemical properties in vitro and induce different pathological features in a transgenic mouse model.
Amyloid pathology induced by different Aβ strains is characterized by different tropism, morphology, and tinctorial properties.
Synthetic Aβ fibrils (2F and 3F) preferentially seed Aβ40 while in vivo‐derived seeds have a preference to recruit Aβ42.
Neuroinflammation induced in treated mice is Aβ strain specific.
Seeded aggregates induced by structurally different Aβ strains in mice display different conformations.
Two structurally defined Aβ conformational variants differ in their biochemical properties in vitro and induce different pathological features in a transgenic mouse model.
The expression of glutaminase in glial cells has been a controversial issue and matter of debate for many years. Actually, glutaminase is essentially considered as a neuronal marker in brain. ...Astrocytes are endowed with efficient and high capacity transport systems to recapture synaptic glutamate which seems to be consistent with the absence of glutaminase in these glial cells. In this work, a comprehensive study was devised to elucidate expression of glutaminase in neuroglia and, more concretely, in astrocytes. Immunocytochemistry in rat and human brain tissues employing isoform‐specific antibodies revealed expression of both Gls and Gls2 glutaminase isozymes in glutamatergic and GABAergic neuronal populations as well as in astrocytes. Nevertheless, there was a different subcellular distribution: Gls isoform was always present in mitochondria while Gls2 appeared in two different locations, mitochondria and nucleus. Confocal microscopy and double immunofluorescence labeling in cultured astrocytes confirmed the same pattern previously seen in brain tissue samples. Astrocytic glutaminase expression was also assessed at the mRNA level, real‐time quantitative RT‐PCR detected transcripts of four glutaminase isozymes but with marked differences on their absolute copy number: the predominance of Gls isoforms over Gls2 transcripts was remarkable (ratio of 144:1). Finally, we proved that astrocytic glutaminase proteins possess enzymatic activity by in situ activity staining: concrete populations of astrocytes were labeled in the cortex, cerebellum and hippocampus of rat brain demonstrating functional catalytic activity. These results are relevant for the stoichiometry of the Glu/Gln cycle at the tripartite synapse and suggest novel functions for these classical metabolic enzymes. GLIA 2015;63:365–382
Main Points
This is the first comprehensive report demonstrating astroglial glutaminase expression at three different levels: mRNA, protein and enzymatic activity.
Astrocytes express both Gls and Gls2 glutaminase isoforms with a clear subcellular segregation involving mitochondria and cell nuclei.
Inhibitory GABAergic neurons also express Gls and Gls2 protein isoforms.
Mitochondrial expression of glutaminase isoforms is relevant for both astrocytic energy metabolism and Glu/Gln cycle while nuclear expression might be associated with transcriptional regulation.
Abstract
In congenital hydrocephalus, cerebrospinal fluid accumulation is associated with increased intracranial pressure (ICP), ischemia/hypoxia, metabolic impairment, neuronal damage, and ...astrocytic reaction. The aim of this study was to identify whether a metabolite profile revealing tissue responses according to the severity of hydrocephalus can be detected. The hyh mutant mouse used for this study exhibits 2 different forms of hydrocephalus, severe and moderate. In a comprehensive investigation into the 2 progressions of hydrocephalus, mice with severe hydrocephalus were found to have higher ICP and astrocytic reaction. Several metabolites from the mouse brain cortex were analyzed with 1H high-resolution magic angle spinning nuclear magnetic resonance (1H HR-MAS NMR) spectroscopy. A differential profile for metabolites including glutamate and glutamine was found to correlate with the severity of hydrocephalus and can be explained due to differential astrocytic reactions, neurodegenerative conditions, and the presence of ischemia. The glutamate transporter EAAT2 and the metabolite taurine were found to be key histopathological markers of affected parenchymata. In conclusion, a differential metabolite profile can be detected according to the severity of hydrocephalus and associated ICP and therefore can be used to monitor the efficacy of experimental therapies.
PDF
