Stem cell proliferation during in vitro development of the model cestode Mesocestoides corti from larva to adult worm

<p>Abstract</p> <p>Background</p> <p>In free-living flatworms somatic differentiated cells do not divide, and a separate population of stem cells (called neoblasts) is responsible for cell proliferation and renewal. In cestodes, there is evidence that similar mechanisms of cell renewal exist.</p> <p>Results</p> <p>In this work, we have characterized proliferative cells during the development of the model cestode <it>Mesocestoides corti </it>from larva (tetrathyridium) to young segmented worm. This was done by two complementary strategies with congruent results: characterizing cells in S phase and their progeny by incorporation of 5-bromo-2'-deoxyuridine, and characterizing cells in M phase by arresting mitotic cells with colchicine and studying their morphology and distribution. Proliferative cells are localized only in the inner parenchyma, particularly in close proximity to the inner muscle layer, but not in the cortical parenchyma nor in the sub-tegumental tissue. After proliferation some of these cells migrate to the outer regions were they differentiate. In the larvae, proliferative cells are more abundant in the anterior regions (scolex and neck), and their number diminishes in an antero-posterior way. During the development of adult segments periodic accumulation of proliferative cells are observed, including a central mass of cells that constitutes the genital primordium, which grows at least in part due to <it>in situ </it>proliferation. In later segments, the inner cells of genital primordia cease to proliferate and adopt a compact distribution, and proliferative cells are also found in the testes primordia.</p> <p>Conclusions</p> <p>Proliferative cells have a characteristic localization and morphology throughout development from larva to adult of <it>Mesocestoides corti</it>, which is similar, and probably evolutionary conserved, to that described in other model cestodes. The characteristics of proliferative cells suggest that these consist of undifferentiated stem cells.</p

An Overview of the Role of Lipofuscin in Age-Related Neurodegeneration

Despite aging being by far the greatest risk factor for highly prevalent neurodegenerative disorders, the molecular underpinnings of age-related brain changes are still not well understood, particularly the transition from normal healthy brain aging to neuropathological aging. Aging is an extremely complex, multifactorial process involving the simultaneous interplay of several processes operating at many levels of the functional organization. The buildup of potentially toxic protein aggregates and their spreading through various brain regions has been identified as a major contributor to these pathologies. One of the most striking morphologic changes in neurons during normal aging is the accumulation of lipofuscin (LF) aggregates, as well as, neuromelanin pigments. LF is an autofluorescent lipopigment formed by lipids, metals and misfolded proteins, which is especially abundant in nerve cells, cardiac muscle cells and skin. Within the Central Nervous System (CNS), LF accumulates as aggregates, delineating a specific senescence pattern in both physiological and pathological states, altering neuronal cytoskeleton and cellular trafficking and metabolism, and being associated with neuronal loss, and glial proliferation and activation. Traditionally, the accumulation of LF in the CNS has been considered a secondary consequence of the aging process, being a mere bystander of the pathological buildup associated with different neurodegenerative disorders. Here, we discuss recent evidence suggesting the possibility that LF aggregates may have an active role in neurodegeneration. We argue that LF is a relevant effector of aging that represents a risk factor or driver for neurodegenerative disorders

Curcumin and Ethanol Effects in Trembler-J Schwann Cell Culture.

Charcot-Marie-Tooth (CMT) syndrome is the most common progressive human motor and sensory peripheral neuropathy. CMT type 1E is a demyelinating neuropathy affecting Schwann cells due to peripheral-myelin-protein-22 (PMP22) mutations, modelized by Trembler-J mice. Curcumin, a natural polyphenol compound obtained from turmeric (Curcuma longa), exhibits dose- and time-varying antitumor, antioxidant and neuroprotective properties, however, the neurotherapeutic actions of curcumin remain elusive. Here, we propose curcumin as a possible natural treatment capable of enhancing cellular detoxification mechanisms, resulting in an improvement of the neurodegenerative Trembler-J phenotype. Using a refined method for obtaining enriched Schwann cell cultures, we evaluated the neurotherapeutic action of low dose curcumin treatment on the PMP22 expression, and on the chaperones and autophagy/mammalian target of rapamycin (mTOR) pathways in Trembler-J and wild-type genotypes. In wild-type Schwann cells, the action of curcumin resulted in strong stimulation of the chaperone and macroautophagy pathway, whereas the modulation of ribophagy showed a mild effect. However, despite the promising neuroprotective effects for the treatment of neurological diseases, we demonstrate that the action of curcumin in Trembler-J Schwann cells could be impaired due to the irreversible impact of ethanol used as a common curcumin vehicle necessary for administration. These results contribute to expanding our still limited understanding of PMP22 biology in neurobiology and expose the intrinsic lability of the neurodegenerative Trembler-J genotype. Furthermore, they unravel interesting physiological mechanisms of cellular resilience relevant to the pharmacological treatment of the neurodegenerative Tremble J phenotype with curcumin and ethanol. We conclude that the analysis of the effects of the vehicle itself is an essential and inescapable step to comprehensibly assess the effects and full potential of curcumin treatment for therapeutic purposes.TThis research was funded by the Comisión Sectorial de Investigación Científica de la Universidad de la República (CSIC I+D, 2013), Agencia Nacional de Investigación e Innovación (ANII, FCE_1_2019_1_155539) and Programa de Desarrollo de Ciencias Básicas (PEDECIBA, CCA-Bio/Res. 6.1-2/4/2019). This work was also supported by a grant PID2019-110401RB-100 from the Spanish, Ministry of Science and Innovation and the Spanish CIBERNED network (M.C.).S

Keys for the identification of genera and species of limnoterrestrial tardigrades (Tardigrada) from the Parque Nacional Nahuel Huapi and surroundings (Patagonia, Argentina)

La información acerca de la diversidad del Phylum Tardigrada en la Argentina yen particular en la región patagónica se encuentra fragmentada y dispersa. En esta contribución se presenta una clave para la identificación de los 23 géneros y 49 especies de tardígrados limnoterrestres registrados hasta el momento en el área del Parque Nacional Nahuel Huapi y sus alrededores.The information about the diversity of the Phylum Tardigrada in Argentina and particularly in the Patagonian region is fragmented and dispersed. In this contribution, keys for the identification of the 23 genera and 49 species of limnoterrestrial tardigrades registered up to now in the area of the Nahuel Huapi National Park and surroundings are presented.Fil: Meier, María Florencia. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche; ArgentinaFil: Rocha, Alejandra Mariana. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Biológicas; ArgentinaFil: Kun, Marcelo Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Messuti, Maria Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; Argentin

Poly(ADP-ribosylation) is present in murine sciatic nerve fibers and is altered in a Charcot-Marie-Tooth-1E neurodegenerative model

Background. Poly-ADP-ribose (PAR) is a polymer synthesized by poly-ADP-ribose polymerases (PARPs) as a postranslational protein modification and catabolized mainly by poly-ADP-ribose glycohydrolase (PARG). In spite of the existence of cytoplasmic PARPs and PARG, research has been focused on nuclear PARPs and PAR, demonstrating roles in the maintenance of chromatin architecture and the participation in DNA damage responses and transcriptional regulation. We have recently detected non-nuclear PAR structurally and functionally associated to the E-cadherin rich zonula adherens and the actin cytoskeleton of VERO epithelial cells. Myelinating Schwann cells (SC) are stabilized by E-cadherin rich autotypic adherens junctions (AJ). We wondered whether PAR would map to these regions. Besides, we have demonstrated an altered microfilament pattern in peripheral nerves of Trembler-J (Tr-J) model of CMT1-E. We hypothesized that cytoplasmic PAR would accompany such modified F-actin pattern. Methods. Wild-type (WT) and Tr-J mice sciatic nerves cryosections were subjected to immunohistofluorescence with anti-PAR antibodies (including antibody validation), F-actin detection with a phalloidin probe and DAPI/DNA counterstaining. Confocal image stacks were subjected to a colocalization highlighter and to semi-quantitative image analysis. Results. We have shown for the first time the presence of PAR in sciatic nerves. Cytoplasmic PAR colocalized with F-actin at non-compact myelin regions in WT nerves. Moreover, in Tr-J, cytoplasmic PAR was augmented in close correlation with actin. In addition, nuclear PAR was detected in WT SC and was moderately increased in Tr-J SC. Discussion. The presence of PAR associated to non-compact myelin regions (which constitute E-cadherin rich autotypic AJ /actin anchorage regions) and the co-alterations experienced by PAR and the actin cytoskeleton in epithelium and nerves, suggest that PAR may be a constitutive component of AJ /actin anchorage regions. Is PAR stabilizing the AJ -actin complexes? This question has strong implications in structural cell biology and cell signaling networks. Moreover, if PAR played a stabilizing role, such stabilization could participate in the physiological control of axonal branching. PARP and PAR alterations exist in several neurodegenerative pathologies including Alzheimer's, Parkinson's and Hungtington's diseases. Conversely, PARP inhibition decreases PAR and promotes neurite outgrowth in cortical neurons in vitro. Coherently, the PARP inhibitor XAV939 improves myelination in vitro, ex vivo and in vivo. Until now such results have been interpreted in terms of nuclear PARP activity. Our results indicate for the first time the presence of PARylation in peripheral nerve fibers, in a healthy environment. Besides, we have evidenced a PARylation increase in Tr-J, suggesting that the involvement of cytoplasmic PARPs and PARylation in normal and neurodegenerative conditions should be re-evaluated

Publisher Correction : Intensity distribution segmentation in ultrafast Doppler combined with scanning laser confocal microscopy for assessing vascular changes associated with ageing in murine hippocampi

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Intensity distribution segmentation in ultrafast Doppler combined with scanning laser confocal microscopy for assessing vascular changes associated with ageing in murine hippocampi

Acknowledgements This work was mainly funded by the Agencia Nacional de Investigación e Innovación (ANII), grant FCE_1_2019_1_155539. Te authors also thank the support of PEDECIBA, CSIC-UdelaR and the Institut Franco—Uruguayen de Physique (IFUP), LIA-CNRS-UdelaR. J.P.D., C.N., N.R., A.K. and J.Br. thank SNI-ANII. M.A.F. thanks the support of ANII through POS_NAC_M_2020_1_164127 scholarship. M.M. thanks the support of ANII through POS_FCE_2020_1_1009181 scholarship. N.R. thanks the support of CSIC I+D group grant CSIC2018—FID 13—Grupo ID 722.Peer reviewedPublisher PD

Colocalization Analysis of Peripheral Myelin Protein-22 and Lamin-B1 in the Schwann Cell Nuclei of Wt and TrJ Mice

Myelination of the peripheral nervous system requires Schwann cells (SC) differentiation into the myelinating phenotype. The peripheral myelin protein-22 (PMP22) is an integral membrane glycoprotein, expressed in SC. It was initially described as a growth arrest-specific (gas3) gene product, up-regulated by serum starvation. PMP22 mutations were pathognomonic for human hereditary peripheral neuropathies, including the Charcot-Marie-Tooth disease (CMT). Trembler-J (TrJ) is a heterozygous mouse model carrying the same pmp22 point mutation as a CMT1E variant. Mutations in lamina genes have been related to a type of peripheral (CMT2B1) or central (autosomal dominant leukodystrophy) neuropathy. We explore the presence of PMP22 and Lamin B1 in Wt and TrJ SC nuclei of sciatic nerves and the colocalization of PMP22 concerning the silent heterochromatin (HC: DAPI-dark counterstaining), the transcriptionally active euchromatin (EC), and the nuclear lamina (H3K4m3 and Lamin B1 immunostaining, respectively). The results revealed that the number of TrJ SC nuclei in sciatic nerves was greater, and the SC volumes were smaller than those of Wt. The myelin protein PMP22 and Lamin B1 were detected in Wt and TrJ SC nuclei and predominantly in peripheral nuclear regions. The level of PMP22 was higher, and those of Lamin B1 lower in TrJ than in Wt mice. The level of PMP22 was higher, and those of Lamin B1 lower in TrJ than in Wt mice. PMP22 colocalized more with Lamin B1 and with the transcriptionally competent EC, than the silent HC with differences between Wt and TrJ genotypes. The results are discussed regarding the probable nuclear role of PMP22 and the relationship with TrJ neuropathy.This research was funded by the Comisión Sectorial de Investigación Científica de la Universidad de la República (CSIC I+D, 2013), Agencia Nacional de Investigación e Innovación (ANII, FCE_1_2019_1_155539) and Programa de Desarrollo de Ciencias Básicas (PEDECIBA, annual fund allocation for academics).S

In vivo ultrafast Doppler imaging combined with confocal microscopy and behavioral approaches to gain insight into the central expression of Peripheral Neuropathy in Trembler-J Mice

Funding: Agencia Nacional de Investigación e Innovación (ANII), grant FCE_1_2019_1_155539. PEDECIBA, CSIC-UdelaR and the Institut Franco—Uruguayen de Physique (IFUP), LIA-CNRS-UdelaR. SNI-ANII (J.P.D., C.N., N.R., A.K. and J.BR.). ANII- POS_NAC_M_2020_1_164127 (M.A.F.).ANII- POS_FCE_2020_1_1009181 (M.M.B). CSIC I+D group grant CSIC2018—FID 13—Grupo ID 722 (N.R.). PID2019-110401RB-100 from the Spanish, Ministry of Science and Innovation and the Spanish CIBERNED network (M.C.). Acknowledgments: We would especially like to thank Dr. Cecilia Scorza, head of the Department of Experimental Neuropharmacology - Instituto de Investigaciones Biológicas Clemente Estable,Peer reviewedPublisher PD