Últimos artículos publicados por el Departamento

CD300f immunoreceptor is associated with major depressive disorder and decreased microglial metabolic fitness

Mié, 11/03/2020 - 07:00

Proc Natl Acad Sci U S A. 2020 Mar 24;117(12):6651-6662. doi: 10.1073/pnas.1911816117. Epub 2020 Mar 9.

ABSTRACT

A role for microglia in neuropsychiatric diseases, including major depressive disorder (MDD), has been postulated. Regulation of microglial phenotype by immune receptors has become a central topic in many neurological conditions. We explored preclinical and clinical evidence for the role of the CD300f immune receptor in the fine regulation of microglial phenotype and its contribution to MDD. We found that a prevalent nonsynonymous single-nucleotide polymorphism (C/T, rs2034310) of the human CD300f receptor cytoplasmic tail inhibits the protein kinase C phosphorylation of a threonine and is associated with protection against MDD, mainly in women. Interestingly, CD300f-/- mice displayed several characteristic MDD traits such as augmented microglial numbers, increased interleukin 6 and interleukin 1 receptor antagonist messenger RNA, alterations in synaptic strength, and noradrenaline-dependent and persistent depressive-like and anhedonic behaviors in females. This behavioral phenotype could be potentiated inducing the lipopolysaccharide depression model. RNA sequencing and biochemical studies revealed an association with impaired microglial metabolic fitness. In conclusion, we report a clear association that links the function of the CD300f immune receptor with MDD in humans, depressive-like and anhedonic behaviors in female mice, and altered microglial metabolic reprogramming.

PMID:32152116 | PMC:PMC7104369 | DOI:10.1073/pnas.1911816117

Spotlight edition on South America

Jue, 27/02/2020 - 08:00

Gene Ther. 2020 Feb;27(1-2):1. doi: 10.1038/s41434-020-0129-9. Epub 2020 Feb 25.

NO ABSTRACT

PMID:32099107 | DOI:10.1038/s41434-020-0129-9

A novel form of Deleted in breast cancer 1 (DBC1) lacking the N-terminal domain does not bind SIRT1 and is dynamically regulated in vivo

Mié, 09/10/2019 - 07:00

Sci Rep. 2019 Oct 7;9(1):14381. doi: 10.1038/s41598-019-50789-7.

ABSTRACT

The protein Deleted in Breast Cancer-1 is a regulator of several transcription factors and epigenetic regulators, including HDAC3, Rev-erb-alpha, PARP1 and SIRT1. It is well known that DBC1 regulates its targets, including SIRT1, by protein-protein interaction. However, little is known about how DBC1 biological activity is regulated. In this work, we show that in quiescent cells DBC1 is proteolytically cleaved, producing a protein (DN-DBC1) that misses the S1-like domain and no longer binds to SIRT1. DN-DBC1 is also found in vivo in mouse and human tissues. Interestingly, DN-DBC1 is cleared once quiescent cells re-enter to the cell cycle. Using a model of liver regeneration after partial hepatectomy, we found that DN-DBC1 is down-regulated in vivo during regeneration. In fact, WT mice show a decrease in SIRT1 activity during liver regeneration, coincidentally with DN-DBC1 downregulation and the appearance of full length DBC1. This effect on SIRT1 activity was not observed in DBC1 KO mice. Finally, we found that DBC1 KO mice have altered cell cycle progression and liver regeneration after partial hepatectomy, suggesting that DBC1/DN-DBC1 transitions play a role in normal cell cycle progression in vivo after cells leave quiescence. We propose that quiescent cells express DN-DBC1, which either replaces or coexist with the full-length protein, and that restoring of DBC1 is required for normal cell cycle progression in vitro and in vivo. Our results describe for the first time in vivo a naturally occurring form of DBC1, which does not bind SIRT1 and is dynamically regulated, thus contributing to redefine the knowledge about its function.

PMID:31591441 | PMC:PMC6779753 | DOI:10.1038/s41598-019-50789-7

Signaling pathways in cytoskeletal responses to plasma membrane depolarization in corneal endothelial cells

Vie, 20/09/2019 - 07:00

J Cell Physiol. 2020 Mar;235(3):2947-2962. doi: 10.1002/jcp.29200. Epub 2019 Sep 18.

ABSTRACT

In previous work, we reported that plasma membrane potential depolarization (PMPD) provokes cortical F-actin remodeling in bovine corneal endothelial (BCE) cells in culture, which eventually leads to the appearance of intercellular gaps. In kidney epithelial cells it has been shown that PMPD determines an extracellular-signal-regulated kinase (ERK)/Rho-dependent increase in diphosphorylated myosin light chain (ppMLC). The present study investigated the signaling pathways involved in the response of BCE cells to PMPD. Differently to renal epithelial cells, we observed that PMPD leads to a decrease in monophosphorylated MLC (pMLC) without affecting diphosphorylated MLC. Also, that the pMLC reduction is a consequence of cyclic adenosine 3',5'-monophosphate (cAMP)/protein kinase A (PKA) activation. In addition, we found evidence that the cAMP increase mostly depends on soluble adenylyl cyclase activity. Inhibition of this enzyme reduces the effect of PMPD on the cAMP rise, F-actin remodeling, and pMLC decrease. No changes in phosho-ERK were observed, although we could determine that RhoA undergoes activation. Our results suggested that active RhoA is not involved in the intercellular gap formation. Overall, the findings of this study support the view that, differently to renal epithelial cells, in BCE cells PMPD determines cytoskeletal reorganization via activation of the cAMP/PKA pathway.

PMID:31535377 | DOI:10.1002/jcp.29200

Preoptic Area Activation and Vasotocin Involvement in the Reproductive Behavior of a Weakly Pulse-Type Electric Fish, <em>Brachyhypopomus gauderio</em>

Jue, 29/08/2019 - 07:00

Front Integr Neurosci. 2019 Aug 13;13:37. doi: 10.3389/fnint.2019.00037. eCollection 2019.

ABSTRACT

Social behavior exhibits a wide diversity among vertebrates though it is controlled by a conserved neural network, the social behavior network (SBN). The activity of the SBN is shaped by hypothalamic nonapeptides of the vasopressin-oxytocin family. The weakly electric fish Brachyhypopomus gauderio emits social electrical signals during courtship. Three types of vasotocin (AVT) cells occur in the preoptic area (POA), one of the SBN nodes. In this study, we aimed to test if POA neurons of the nucleus preopticus ventricularis anterior (PPa) and posterior (PPp), and in particular AVT+ cells, were activated by social stimuli using a 2-day behavioral protocol. During the first night, male-female dyads were recorded to identify courting males. During the second night, these males were divided in two experimental conditions: isolated and social (male with a female). Both AVT cells and the cellular activation of the POA neurons (measured by FOS) were identified. We found that the PPa of social males showed more FOS+ cells than the PPa of isolated males, and that the PPa had more AVT+ cells in social males than in isolated males. The double-immunolabeling for AVT and FOS indicated the activation of AVT+ neurons. No significant differences in the activation of AVT+ cells were found between conditions, but a clear association was observed between the number of AVT+ cells and certain behavioral traits. In addition, a different activation of AVT+ cell-types was observed for social vs. isolated males. We conclude that the POA of B. gauderio exhibits changes induced by social stimuli in reproductive context, involving an increase in AVT production and a different profile activation among AVT+ cell populations.

PMID:31456670 | PMC:PMC6700327 | DOI:10.3389/fnint.2019.00037

Mitofusins modulate the increase in mitochondrial length, bioenergetics and secretory phenotype in therapy-induced senescent melanoma cells

Jue, 22/08/2019 - 07:00

Biochem J. 2019 Sep 10;476(17):2463-2486. doi: 10.1042/BCJ20190405.

ABSTRACT

Cellular senescence is an endpoint of chemotherapy, and targeted therapies in melanoma and the senescence-associated secretory phenotype (SASP) can affect tumor growth and microenvironment, influencing treatment outcomes. Metabolic interventions can modulate the SASP, and an enhanced mitochondrial energy metabolism supports resistance to therapy in melanoma cells. Herein, we assessed the mitochondrial function of therapy-induced senescent melanoma cells obtained after exposing the cells to temozolomide (TMZ), a methylating chemotherapeutic agent. Senescence induction in melanoma was accompanied by a substantial increase in mitochondrial basal, ATP-linked, and maximum respiration rates and in coupling efficiency, spare respiratory capacity, and respiratory control ratio. Further examinations revealed an increase in mitochondrial mass and length. Alterations in mitochondrial function and morphology were confirmed in isolated senescent cells, obtained by cell-size sorting. An increase in mitofusin 1 and 2 (MFN1 and 2) expression and levels was observed in senescent cells, pointing to alterations in mitochondrial fusion. Silencing mitofusin expression with short hairpin RNA (shRNA) prevented the increase in mitochondrial length, oxygen consumption rate and secretion of interleukin 6 (IL-6), a component of the SASP, in melanoma senescent cells. Our results represent the first in-depth study of mitochondrial function in therapy-induced senescence in melanoma. They indicate that senescence increases mitochondrial mass, length and energy metabolism; and highlight mitochondria as potential pharmacological targets to modulate senescence and the SASP.

PMID:31431479 | PMC:PMC6735661 | DOI:10.1042/BCJ20190405

Glutaric Acid Affects Pericyte Contractility and Migration: Possible Implications for GA-I Pathogenesis

Lun, 20/05/2019 - 07:00

Mol Neurobiol. 2019 Nov;56(11):7694-7707. doi: 10.1007/s12035-019-1620-4. Epub 2019 May 18.

ABSTRACT

Glutaric acidemia I (GA-I) is an inherited neurometabolic childhood disease characterized by bilateral striatal neurodegeneration upon brain accumulation of millimolar concentrations of glutaric acid (GA) and related metabolites. Vascular dysfunction, including abnormal cerebral blood flow and blood-brain barrier damage, is an early pathological feature in GA-I, although the affected cellular targets and underlying mechanisms remain unknown. In the present study, we have assessed the effects of GA on capillary pericyte contractility in cerebral cortical slices and pericyte cultures, as well as on the survival, proliferation, and migration of cultured pericytes. GA induced a significant reduction in capillary diameter at distances up to ~ 10 μm from the center of pericyte somata. However, GA did not affect the contractility of cultured pericytes, suggesting that the response elicited in slices may involve GA evoking pericyte contraction by acting on other cellular components of the neurovascular unit. Moreover, GA indirectly inhibited migration of cultured pericytes, an effect that was dependent on soluble glial factors since it was observed upon application of conditioned media from GA-treated astrocytes (CM-GA), but not upon direct GA addition to the medium. Remarkably, CM-GA showed increased expression of cytokines and growth factors that might mediate the effects of increased GA levels not only on pericyte migration but also on vascular permeability and angiogenesis. These data suggest that some effects elicited by GA might be produced by altering astrocyte-pericyte communication, rather than directly acting on pericytes. Importantly, GA-evoked alteration of capillary pericyte contractility may account for the reduced cerebral blood flow observed in GA-I patients.

PMID:31104295 | DOI:10.1007/s12035-019-1620-4

Transcriptomic analysis of fetal membranes reveals pathways involved in preterm birth

Mié, 03/04/2019 - 07:00

BMC Med Genomics. 2019 Apr 1;12(1):53. doi: 10.1186/s12920-019-0498-3.

ABSTRACT

BACKGROUND: Preterm birth (PTB), defined as infant delivery before 37 weeks of completed gestation, results from the interaction of both genetic and environmental components and constitutes a complex multifactorial syndrome. Transcriptome analysis of PTB has proven challenging because of the multiple causes of PTB and the numerous maternal and fetal gestational tissues that must interact to facilitate parturition. The transcriptome of the chorioamnion membranes at the site of rupture in PTB and term fetuses may reflect the molecular pathways of preterm labor.

METHODS: In this work, chorioamnion membranes from severe preterm and term fetuses were analyzed using RNA sequencing. Functional annotations and pathway analysis of differentially expressed genes were performed with the GAGE and GOSeq packages. A subset of differentially expressed genes in PTB was validated in a larger cohort using qRT-PCR and by comparing our results with genes and pathways previously reported in the literature.

RESULTS: A total of 270 genes were differentially expressed (DE): 252 were upregulated and 18 were down-regulated in severe preterm births relative to term births. Inflammatory and immunological pathways were upregulated in PTB. Both types of pathways were previously suggested to lead to PTB. Pathways that were not previously reported in PTB, such as the hemopoietic pathway, appeared upregulated in preterm membranes. A group of 18 downregulated genes discriminated between term and severe preterm cases. These genes potentially characterize a severe preterm transcriptome pattern and therefore are candidate genes for understanding the syndrome. Some of the downregulated genes are involved in the nervous system, morphogenesis (WNT1, DLX5, PAPPA2) and ion channel complexes (KCNJ16, KCNB1), making them good candidates as biomarkers of PTB.

CONCLUSIONS: The identification of this DE gene pattern will help with the development of a multi-gene disease classifier. These markers were generated in an admixed South American population in which PTB has a high incidence. Since the genetic background may differentially impact different populations, it is necessary to include populations such as those from South America and Africa, which are usually excluded from high-throughput approaches. These classifiers should be compared to those in other populations to obtain a global landscape of PTB.

PMID:30935390 | PMC:PMC6444860 | DOI:10.1186/s12920-019-0498-3

Safe and neuroprotective vectors for long-term traumatic brain injury gene therapy

Dom, 31/03/2019 - 07:00

Gene Ther. 2020 Feb;27(1-2):96-103. doi: 10.1038/s41434-019-0073-8. Epub 2019 Mar 29.

ABSTRACT

Traumatic brain injury (TBI) is a complex and progressive brain injury with no approved treatments that needs both short- and long-term therapeutic strategies to cope with the variety of physiopathological mechanisms involved. In particular, neuroinflammation is a key process modulating TBI outcome, and the potentiation of these mechanisms by pro-inflammatory gene therapy vectors could contribute to the injury progression. Here, we evaluate in the controlled cortical impact model of TBI, the safety of integrative-deficient lentiviral vectors (IDLVs) or the non-viral HNRK recombinant modular protein/DNA nanovector. These two promising vectors display different tropisms, transduction efficiencies, short- or long-term transduction or inflammatory activation profile. We show that the brain intraparenchymal injection of these vectors overexpressing green fluorescent protein after a CCI is not neurotoxic, and interestingly, can decrease the short-term sensory neurological deficits, and diminish the brain tissue loss at 90 days post lesion (dpl). Moreover, only IDLVs were able to mitigate the memory deficits elicited by a CCI. These vectors did not alter the microglial or astroglial reactivity at 90 dpl, suggesting that they do not potentiate the on-going neuroinflammation. Taken together, these data suggest that both types of vectors could be interesting tools for the design of gene therapy strategies targeting immediate or long-term neuropathological mechanisms of TBI.

PMID:30926962 | DOI:10.1038/s41434-019-0073-8

Distribution of sperm antigen 6 (SPAG6) and 16 (SPAG16) in mouse ciliated and non-ciliated tissues

Mié, 27/03/2019 - 07:00

J Mol Histol. 2019 Jun;50(3):189-202. doi: 10.1007/s10735-019-09817-z. Epub 2019 Mar 25.

ABSTRACT

The cilia and flagella of eukaryotic cells serve many functions, exhibiting remarkable conservation of both structure and molecular composition in widely divergent eukaryotic organisms. SPAG6 and SPAG16 are the homologous in the mice to Chlamydomonas reinhardtii PF16 and PF20. Both proteins are associated with the axonemal central apparatus and are essential for ciliary and flagellar motility in mammals. Recent data derived from high-throughput studies revealed expression of these genes in tissues that do not contain motile cilia. However, the distribution of SPAG6 and SPAG16 in ciliated and non-ciliated tissues is not completely understood. In this work, we performed a quantitative analysis of the expression of Spag6 and Spag16 genes in parallel with the immune-localization of the proteins in several tissues of adult mice. Expression of mRNA was higher in the testis and tissues bearing motile cilia than in the other analyzed tissues. Both proteins were present in ciliated and non-ciliated tissues. In the testis, SPAG6 was detected in spermatogonia, spermatocytes, and in the sperm flagella whereas SPAG16 was found in spermatocytes and in the sperm flagella. In addition, both proteins were detected in the cytoplasm of cells from the brain, spinal cord, and ovary. A small isoform of SPAG16 was localized in the nucleus of germ cells and some neurons. In a parallel set of experiments, we overexpressed EGFP-SPAG6 in cultured cells and observed that the protein co-localized with a subset of acetylated cytoplasmic microtubules. A role of these proteins stabilizing the cytoplasmic microtubules of eukaryotic cells is discussed.

PMID:30911868 | DOI:10.1007/s10735-019-09817-z

Ibogaine Administration Modifies GDNF and BDNF Expression in Brain Regions Involved in Mesocorticolimbic and Nigral Dopaminergic Circuits

Jue, 21/03/2019 - 07:00

Front Pharmacol. 2019 Mar 5;10:193. doi: 10.3389/fphar.2019.00193. eCollection 2019.

ABSTRACT

Ibogaine is an atypical psychedelic alkaloid, which has been subject of research due to its reported ability to attenuate drug-seeking behavior. Recent work has suggested that ibogaine effects on alcohol self-administration in rats are related to the release of Glial cell Derived Neurotrophic Factor (GDNF) in the Ventral Tegmental Area (VTA), a mesencephalic region which hosts the soma of dopaminergic neurons. Although previous reports have shown ibogaine's ability to induce GDNF expression in rat midbrain, there are no studies addressing its effect on the expression of GDNF and other neurotrophic factors (NFs) such as Brain Derived Neurotrophic Factor (BDNF) or Nerve Growth Factor (NGF) in distinct brain regions containing dopaminergic neurons. In this work, we examined the effect of ibogaine acute administration on the expression of these NFs in the VTA, Prefrontal Cortex (PFC), Nucleus Accumbens (NAcc) and the Substantia Nigra (SN). Rats were i.p. treated with ibogaine 20 mg/kg (I20), 40 mg/kg (I40) or vehicle, and NFs expression was analyzed after 3 and 24 h. At 24 h an increase of the expression of the NFs transcripts was observed in a site and dose dependent manner. Only for I40, GDNF was selectively upregulated in the VTA and SN. Both doses elicited a large increase in the expression of BDNF transcripts in the NAcc, SN and PFC, while in the VTA a significant effect was found only for I40. Finally, NGF mRNA was upregulated in all regions after I40, while I20 showed a selective upregulation in PFC and VTA. Regarding protein levels, an increase of GDNF was observed in the VTA only for I40 but no significant increase for BDNF was found in all the studied areas. Interestingly, an increase of proBDNF was detected in the NAcc for both doses. These results show for the first time a selective increase of GDNF specifically in the VTA for I40 but not for I20 after 24 h of administration, which agrees with the effective dose found in previous self-administration studies in rodents. Further research is needed to understand the contribution of these changes to ibogaine's ability to attenuate drug-seeking behavior.

PMID:30890941 | PMC:PMC6411846 | DOI:10.3389/fphar.2019.00193

Leukocyte Profiles Reflect Geographic Range Limits in a Widespread Neotropical Bat

Sáb, 16/03/2019 - 07:00

Integr Comp Biol. 2019 Nov 1;59(5):1176-1189. doi: 10.1093/icb/icz007.

ABSTRACT

Quantifying how the environment shapes host immune defense is important for understanding which wild populations may be more susceptible or resistant to pathogens. Spatial variation in parasite risk, food and predator abundance, and abiotic conditions can each affect immunity, and these factors can also manifest at both local and biogeographic scales. Yet identifying predictors and the spatial scale of their effects is limited by the rarity of studies that measure immunity across many populations of broadly distributed species. We analyzed leukocyte profiles from 39 wild populations of the common vampire bat (Desmodus rotundus) across its wide geographic range throughout the Neotropics. White blood cell differentials varied spatially, with proportions of neutrophils and lymphocytes varying up to six-fold across sites. Leukocyte profiles were spatially autocorrelated at small and very large distances, suggesting that local environment and large-scale biogeographic factors influence cellular immunity. Generalized additive models showed that bat populations closer to the northern and southern limits of the species range had more neutrophils, monocytes, and basophils, but fewer lymphocytes and eosinophils, than bats sampled at the core of their distribution. Habitats with access to more livestock also showed similar patterns in leukocyte profiles, but large-scale patterns were partly confounded by time between capture and sampling across sites. Our findings suggest that populations at the edge of their range experience physiologically limiting conditions that predict higher chronic stress and greater investment in cellular innate immunity. High food abundance in livestock-dense habitats may exacerbate such conditions by increasing bat density or diet homogenization, although future spatially and temporally coordinated field studies with common protocols are needed to limit sampling artifacts. Systematically assessing immune function and response over space will elucidate how environmental conditions influence traits relevant to epidemiology and help predict disease risks with anthropogenic disturbance, land conversion, and climate change.

PMID:30873523 | PMC:PMC6907035 | DOI:10.1093/icb/icz007

Experimental polycystic ovarian syndrome is associated with reduced expression and function of P2Y2 receptors in rat theca cells

Jue, 10/01/2019 - 08:00

Mol Reprod Dev. 2019 Mar;86(3):308-318. doi: 10.1002/mrd.23106. Epub 2019 Jan 17.

ABSTRACT

Extracellular purines through specific receptors have been recognized as new regulators of ovarian function. It is known that P2Y2 receptor activity induces theca cell proliferation, we hypothesized that purinergic signaling controls the changes related to hyperthecosis in polycystic ovarian syndrome (PCOS). The aim of this study was to analyze the expression of UTP-sensitive P2Y receptors and their role in theca cells (TC) proliferation in experimentally-induced PCOS (EI-PCOS). In primary cultures of TC from intact rats, all the transcripts of P2Y receptors were detected by polymerase chain reaction; in these cells, UTP (10 μM) induced extracellular signal-regulated kinases (ERK) phosphorylation. Rats with EI-PCOS showed a reduced expression of P2Y2R in TC whereas P2Y4R did not change. By analyzing ERK phosphorylation, it was determined that P2Y2R is the most relevant receptor in TC. UTP promoted cell proliferation in TC from control but not from EI-PCOS rats. The in silico analysis of P2yr2 promoter indicated the presence of androgen response elements; the stimulation of TC primary cultures with testosterone promoted a significant reduction in the expression of the P2yr2 transcript. We concluded that P2Y2R participates in controlling the proliferative rate of TCs from healthy ovaries, but this regulation is lost during EI-PCOS.

PMID:30624816 | DOI:10.1002/mrd.23106

First ovarian response to gonadotrophin stimulation in rats exposed to neonatal androgen excess

Jue, 11/10/2018 - 07:00

J Mol Histol. 2018 Dec;49(6):631-637. doi: 10.1007/s10735-018-9800-5. Epub 2018 Oct 9.

ABSTRACT

This study analyzes the effects of neonatal androgenization on follicular growth and first ovulation in response to gonadotrophins, using a model of exogenous stimulation or the use of subcutaneous ovary grafts in castrated animals to replace the hypothalamus-pituitary signal. Neonatal rats (days 1-5) were treated with testosterone, dihydrotestosterone or vehicle. At juvenile period, rats were stimulated with PMSG, hCG (alone or combined) or used as ovarian donors to be grafted on castrated adult female rats. Ovulation and ovarian histology were analyzed in both groups. Animals treated with vehicle or dihydrotestosterone stimulated with gonadotrophins (pharmacological or by using an ovary graft) ovulated, showing a normal histological morphology whereas rats exposed to testosterone and injected with the same doses of gonadotrophins did not it. In this group, ovulation was reached using a higher dose of hCG. Ovaries in the testosterone group were characterized by the presence of follicles with atretic appearance and a larger size than those observed in control or dihydrotestosterone groups. A similar appearance was observed in testosterone ovary grafts although luteinization and some corpora lutea were also identified. Our findings suggest that neonatal exposure to aromatizable androgens induces a more drastic signalling on the ovarian tissue that those driven by non-aromatizable androgens in response to gonadotrophins.

PMID:30302594 | DOI:10.1007/s10735-018-9800-5

Impact of monomeric, oligomeric and fibrillar alpha-synuclein on astrocyte reactivity and toxicity to neurons

Vie, 07/09/2018 - 07:00

Biochem J. 2018 Oct 11;475(19):3153-3169. doi: 10.1042/BCJ20180297.

ABSTRACT

Synucleinopathies are a group of neurodegenerative disorders characterized by the presence of aggregated and fibrillar forms of alpha-synuclein (α-syn). Here, we analyze the effect of different species of α-syn, including monomeric, oligomeric and fibrillar forms of the protein, on rat astrocytes. Astrocytes treated with these distinct forms of α-syn showed an increase in long and thin processes and glial fibrillary acidic protein expression, indicating cell activation, high levels of intracellular oxidants and increased expression of cytokines. Moreover, astrocytes incubated with the different species induced hippocampal neuronal death in co-culture, and cytotoxicity was particularly enhanced by exposure to fibrillar α-syn. Further exploration of the mechanisms behind astrocyte activation and cytotoxicity revealed differences between the assessed α-syn species. Only oligomers induced mitochondrial dysfunction in astrocytes and significantly increased extracellular hydrogen peroxide production by these cells. Besides, TNF-α and IL-1β (interleukin 1β) expression presented different kinetics and levels depending on which species induced the response. Our data suggest that α-syn species (monomeric, oligomeric and fibrillar) induce astrocyte activation that can lead to neuronal death. Nevertheless, the tested α-syn species act through different preferential mechanisms and potency. All together these results help to understand the effect of α-syn species on astrocyte function and their potential impact on the pathogenesis of Parkinson's disease and related α-synucleinopathies.

PMID:30185433 | DOI:10.1042/BCJ20180297

Mitochondrial Modulation by Dichloroacetate Reduces Toxicity of Aberrant Glial Cells and Gliosis in the SOD1G93A Rat Model of Amyotrophic Lateral Sclerosis

Vie, 31/08/2018 - 07:00

Neurotherapeutics. 2019 Jan;16(1):203-215. doi: 10.1007/s13311-018-0659-7.

ABSTRACT

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by motor neuron (MN) degeneration and gliosis. Neonatal astrocytes obtained from the SOD1G93A rat model of ALS exhibit mitochondrial dysfunction and neurotoxicity that can be reduced by dichloroacetate (DCA), a metabolic modulator that has been used in humans, and shows beneficial effects on disease outcome in SOD1G93A mice. Aberrant glial cells (AbGC) isolated from the spinal cords of adult paralytic SOD1G93A rats exhibit highly proliferative and neurotoxic properties and may contribute to disease progression. Here we analyze the mitochondrial activity of AbGC and whether metabolic modulation would modify their phenotypic profile. Our studies revealed fragmented mitochondria and lower respiratory control ratio in AbGC compared to neonatal SOD1G93A and nontransgenic rat astrocytes. DCA (5 mM) exposure improved AbGC mitochondrial function, reduced their proliferative rate, and importantly, decreased their toxicity to MNs. Furthermore, oral DCA administration (100 mg/kg, 10 days) to symptomatic SOD1G93A rats reduced MN degeneration, gliosis, and the number of GFAP/S100β double-labeled hypertrophic glial cells in the spinal cord. DCA treatment of AbGC reduced extracellular lactate levels indicating that the main recognized DCA action, targeting the pyruvate dehydrogenase kinase/pyruvate dehydrogenase complex, may underlie our findings. Our results show that AbGC metabolic phenotype is related to their toxicity to MNs and indicate that its modulation can reduce glial mediated pathology in the spinal cord. Together with previous findings, these results further support glial metabolic modulation as a valid therapeutic strategy in ALS.

PMID:30159850 | PMC:PMC6361051 | DOI:10.1007/s13311-018-0659-7

CD200 modulates spinal cord injury neuroinflammation and outcome through CD200R1

Mié, 06/06/2018 - 07:00

Brain Behav Immun. 2018 Oct;73:416-426. doi: 10.1016/j.bbi.2018.06.002. Epub 2018 Jun 2.

ABSTRACT

The interaction between CD200 and its receptor CD200R1 is among the central regulators of microglia and macrophage phenotype. However, it remains to be established whether, in the context of a traumatic CNS injury, CD200R1 act as a negative regulator of these particular innate immune cells, and if the exogenous delivery of CD200 may ameliorate neurological deficits. In the present study, we first evaluated whether preventing the local interaction between the pair CD200-CD200R1, by using a selective blocking antibody against CD200R1, has a role on functional and inflammatory outcome after contusion-induced spinal cord injury (SCI) in mice. The injection of the αCD200R1, but not control IgG1, into the lesioned spinal cord immediately after the SCI worsened locomotor performance and exacerbated neuronal loss and demyelination. At the neuroimmunological level, we observed that microglial cells and macrophages showed increased levels of iNOS and Ly6C upon CD200R1 blockade, indicating that the disruption of CD200R1 drove these cells towards a more pro-inflammatory phenotype. Moreover, although CD200R1 blockade had no effect in the initial infiltration of neutrophils into the lesioned spinal cord, it significantly impaired their clearance, which is a key sign of excessive inflammation. Interestingly, intraparenchymal injection of recombinant CD200-His immediately after the injury induced neuroprotection and robust and long-lasting locomotor recovery. In conclusion, this study reveals that interaction of CD200-CD200R1 plays a crucial role in limiting inflammation and lesion progression after SCI, and that boosting the stimulation of this pathway may constitute a new therapeutic approach.

PMID:29870752 | DOI:10.1016/j.bbi.2018.06.002

Profile of Arachidonic Acid-Derived Inflammatory Markers and Its Modulation by Nitro-Oleic Acid in an Inherited Model of Amyotrophic Lateral Sclerosis

Mié, 16/05/2018 - 07:00

Front Mol Neurosci. 2018 Apr 30;11:131. doi: 10.3389/fnmol.2018.00131. eCollection 2018.

ABSTRACT

The lack of current treatments for amyotrophic lateral sclerosis (ALS) highlights the need of a comprehensive understanding of the biological mechanisms of the disease. A consistent neuropathological feature of ALS is the extensive inflammation around motor neurons and axonal degeneration, evidenced by accumulation of reactive astrocytes and activated microglia. Final products of inflammatory processes may be detected as a screening tool to identify treatment response. Herein, we focus on (a) detection of arachidonic acid (AA) metabolization products by lipoxygenase (LOX) and prostaglandin endoperoxide H synthase in SOD1G93A mice and (b) evaluate its response to the electrophilic nitro-oleic acid (NO2-OA). Regarding LOX-derived products, a significant increase in 12-hydroxyeicosatetraenoic acid (12-HETE) levels was detected in SOD1G93A mice both in plasma and brain whereas no changes were observed in age-matched non-Tg mice at the onset of motor symptoms (90 days-old). In addition, 15-hydroxyeicosatetraenoic acid (15-HETE) levels were greater in SOD1G93A brains compared to non-Tg. Prostaglandin levels were also increased at day 90 in plasma from SOD1G93A compared to non-Tg being similar in both types of animals at later stages of the disease. Administration of NO2-OA 16 mg/kg, subcutaneously (s/c) three times a week to SOD1G93A female mice, lowered the observed increase in brain 12-HETE levels compared to the non-nitrated fatty acid condition, and modified many others inflammatory markers. In addition, NO2-OA significantly improved grip strength and rotarod performance compared to vehicle or OA treated animals. These beneficial effects were associated with increased hemeoxygenase 1 (HO-1) expression in the spinal cord of treated mice co-localized with reactive astrocytes. Furthermore, significant levels of NO2-OA were detected in brain and spinal cord from NO2-OA -treated mice indicating that nitro-fatty acids (NFA) cross brain-blood barrier and reach the central nervous system to induce neuroprotective actions. In summary, we demonstrate that LOX-derived oxidation products correlate with disease progression. Overall, we are proposing that key inflammatory mediators of AA-derived pathways may be useful as novel footprints of ALS onset and progression as well as NO2-OA as a promising therapeutic compound.

PMID:29760648 | PMC:PMC5936757 | DOI:10.3389/fnmol.2018.00131

Thy1-YFP-H Mice and the Parallel Rod Floor Test to Evaluate Short- and Long-Term Progression of Traumatic Brain Injury

Jue, 08/03/2018 - 08:00

Curr Protoc Immunol. 2018 Feb 21;120:24.1.1-24.1.25. doi: 10.1002/cpim.42.

ABSTRACT

Traumatic brain injury (TBI) is a leading cause of death and disability and is a risk factor for the later development of neuropsychiatric disorders and neurodegenerative diseases. Many models of TBI have been developed, but their further refinement and a more detailed long-term follow-up is needed. We have used the Thy1-YFP-H transgenic mouse line and the parallel rod floor test to produce an unbiased and robust method for the evaluation of the multiple effects of a validated model of controlled cortical injury. This approach reveals short- and long-term progressive changes, including compromised biphasic motor function up to 85 days post-lesion, which correlates with neuronal atrophy, dendrite and spine loss, and long-term axonal pathology evidenced by axon spheroids and fragmentation. Here we present methods for inducing a controlled cortical injury in the Thy1-YFP-H transgenic mouse line and for evaluating the resulting deficits in the parallel rod floor test. This technique constitutes a new, unbiased, and robust method for the evaluation of motor and behavioral alterations after TBI. © 2018 by John Wiley & Sons, Inc.

PMID:29512144 | DOI:10.1002/cpim.42

Kinesin 1 regulates cilia length through an interaction with the Bardet-Biedl syndrome related protein CCDC28B

Vie, 16/02/2018 - 08:00

Sci Rep. 2018 Feb 14;8(1):3019. doi: 10.1038/s41598-018-21329-6.

ABSTRACT

Bardet-Biedl syndrome (BBS) is a ciliopathy characterized by retinal degeneration, obesity, polydactyly, renal disease and mental retardation. CCDC28B is a BBS-associated protein that we have previously shown plays a role in cilia length regulation whereby its depletion results in shortened cilia both in cells and Danio rerio (zebrafish). At least part of that role is achieved by its interaction with the mTORC2 component SIN1, but the mechanistic details of this interaction and/or additional functions that CCDC28B might play in the context of cilia remain poorly understood. Here we uncover a novel interaction between CCDC28B and the kinesin 1 molecular motor that is relevant to cilia. CCDC28B interacts with kinesin light chain 1 (KLC1) and the heavy chain KIF5B. Notably, depletion of these kinesin 1 components results in abnormally elongated cilia. Furthermore, through genetic interaction studies we demonstrate that kinesin 1 regulates ciliogenesis through CCDC28B. We show that kinesin 1 regulates the subcellular distribution of CCDC28B, unexpectedly, inhibiting its nuclear accumulation, and a ccdc28b mutant missing a nuclear localization motif fails to rescue the phenotype in zebrafish morphant embryos. Therefore, we uncover a previously unknown role of kinesin 1 in cilia length regulation that relies on the BBS related protein CCDC28B.

PMID:29445114 | PMC:PMC5813027 | DOI:10.1038/s41598-018-21329-6

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