Regions Of Central Nervous System Research Articles

Opioid-Induced Hyperalgesia Is Associated with Dysregulation of Circadian Rhythm and Adaptive Immune Pathways in the Mouse Trigeminal Ganglia and Nucleus Accumbens.

The benefits of opioid-based treatments to mitigate chronic pain can be hindered by the side effects of opioid-induced hyperalgesia (OIH) that can lead to higher consumption and risk of addiction. The present study advances the understanding of the molecular mechanisms associated with OIH by comparing mice presenting OIH symptoms in response to chronic morphine exposure (OIH treatment) relative to control mice (CON treatment). Using RNA-Seq profiles, gene networks were inferred in the trigeminal ganglia (TG), a central nervous system region associated with pain signaling, and in the nucleus accumbens (NAc), a region associated with reward dependency. The biological process of nucleic acid processing was over-represented among the 122 genes that exhibited a region-dependent treatment effect. Within the 187 genes that exhibited a region-independent treatment effect, circadian rhythm processes were enriched among the genes over-expressed in OIH relative to CON mice. This enrichment was supported by the differential expression of the period circadian clock 2 and 3 genes (Per2 and Per3). Transcriptional regulators in the PAR bZip family that are influenced by the circadian clock and that modulate neurotransmission associated with pain and drug addiction were also over-expressed in OIH relative to CON mice. Also notable was the under-expression in OIH relative to CON mice of the Toll-like receptor, nuclear factor-kappa beta, and interferon gamma genes and enrichment of the adaptive immune processes. The results from the present study offer insights to advance the effective use of opioids for pain management while minimizing hyperalgesia.

Concentration-dependent effects of CSF1R inhibitors on oligodendrocyte progenitor cells ex vivo and in vivo

Microglia are the principal resident immune cells in the central nervous system (CNS) and play important roles in CNS development, maintenance and repair. The survival and development of microglia depends on colony-stimulating factor 1 receptor (CSF1R), a member of the platelet-derived growth factor receptor (PDGFR) family of tyrosine kinases. Recently pharmacological CSF1R inhibition has been used to investigate the effects of microglial depletion in numerous animal models of CNS disease. However, the effects of CSF1R inhibitors on other cell types in the CNS remains incompletely characterized. In this report, we compared the effect of two commonly used CSF1R inhibitors, PLX5622 and PLX3397, on microglia and oligodendrocyte progenitor cell (OPC) numbers. In ex vivo cerebellar slices and adult mouse brain, both PLX compounds caused robust microglia loss; the kinetics of microglial depletion was more rapid with PLX5622. While high-doses of PLX5622 and PLX3397 reduced OPC number in primary cultures in vitro and ex vivo, low-doses of PLX5622 did not affect the number of OPCs or mature oligodendroglia in culture or in vivo. In adult mice, treatment with PLX5622 had no effect on OPC numbers for 7 days; however, a mild reduction was observed after 21 days in some CNS regions. In contrast, PLX3397 caused significant OPC loss after 7 days of treatment, despite only modest microglia depletion. Neither PLX compound had a remarkable effect on mature oligodendrocytes or myelin protein expression following long-term oral administration. Our results show that CSF1R inhibition with PLX5622 can selectively deplete microglia ex vivo and in vivo without affecting OPC number, demonstrating that microglia are not essential for OPC viability in ex vivo slice cultures or adult CNS tissues.

Leukodystrophy caused by plasmalogen deficiency rescued by glyceryl 1-myristyl ether treatment.

Plasmalogens are the most abundant form of ether phospholipids in myelin and their deficiency causes Rhizomelic Chondrodysplasia Punctata (RCDP), a severe developmental disorder. Using the Gnpat-knockout (KO) mouse as a model of RCDP, we determined the consequences of a plasmalogen deficiency during myelination and myelin homeostasis in the central nervous system (CNS). We unraveled that the lack of plasmalogens causes a generalized hypomyelination in several CNS regions including the optic nerve, corpus callosum and spinal cord. The defect in myelin content evolved to a progressive demyelination concomitant with generalized astrocytosis and white matter-selective microgliosis. Oligodendrocyte precursor cells (OPC) and mature oligodendrocytes were abundant in the CNS of Gnpat KO mice during the active period of demyelination. Axonal loss was minimal in plasmalogen-deficient mice, although axonal damage was observed in spinal cords from aged Gnpat KO mice. Characterization of the plasmalogen-deficient myelin identified myelin basic protein and septin 7 as early markers of dysmyelination, whereas myelin-associated glycoprotein was associated with the active demyelination phase. Using in vitro myelination assays, we unraveled that the intrinsic capacity of oligodendrocytes to ensheath and initiate membrane wrapping requires plasmalogens. The defect in plasmalogens was rescued with glyceryl 1-myristyl ether [1-O-tetradecyl glycerol (1-O-TDG)], a novel alternative precursor in the plasmalogen biosynthesis pathway. 1-O-TDG treatment rescued myelination in plasmalogen-deficient oligodendrocytes and in mutant mice. Our results demonstrate the importance of plasmalogens for oligodendrocyte function and myelin assembly, and identified a novel strategy to promote myelination in nervous tissue.

Autoimmune glial fibrillary acidic protein astrocytopathy.

Purpose of reviewTo describe a recently characterized autoimmune, inflammatory central nervous system (CNS) disorder known as autoimmune glial fibrillary acidic protein (GFAP) astrocytopathy.Recent findingsAffected patients present with symptoms of one or more of meningitis (headache and neck ache), encephalitis (delirium, tremor, seizures, or psychiatric symptoms), and myelitis (sensory symptoms and weakness). Optic disc papillitis (blurred vision) is common. CNS inflammation is evident in characteristic T1 postgadolinium enhancement of GFAP-enriched CNS regions, and lymphocytic cerebrospinal fluid (CSF) white cell count elevation. CSF is more reliable than serum for GFAP-immunoglobulin G (IgG) testing. Ovarian teratoma commonly coexists, particularly among patients with accompanying N-methyl-D-aspartate receptor or aquaporin-4 autoimmunity. Parainfectious autoimmunity is suspected in some other patients, though the culprit organism is rarely verified. Pathophysiologic relevance of T cells is underscored by neuropathology and cases of dysregulated T-cell function (HIV or checkpoint inhibitor cancer therapy). Corticosteroid-responsiveness is a hallmark of the disease. Relapses occur in approximately 20% of patients, necessitating transition to a steroid-sparing drug. Reported outcomes vary, though in the authors’ experience, early and sustained intervention usually portends recovery.SummaryAutoimmune GFAP astrocytopathy is a treatable autoimmune CNS disease diagnosable by GFAP-IgG testing in CSF. This disease presents opportunities to explore novel mechanisms of CNS autoimmunity and inflammation.

Homozygous hydroxymethylbilane synthase knock-in mice provide pathogenic insights into the severe neurological impairments present in human homozygous dominant acute intermittent porphyria.

Acute intermittent porphyria (AIP) is an inborn error of heme biosynthesis due to the deficiency of hydroxymethylbilane synthase (HMBS) activity. Human AIP heterozygotes have episodic acute neurovisceral attacks that typically start after puberty, whereas patients with homozygous dominant AIP (HD-AIP) have early-onset chronic neurological impairment, including ataxia and psychomotor retardation. To investigate the dramatically different manifestations, knock-in mice with human HD-AIP missense mutations c.500G>A (p.Arg167Glu) or c.518_519GC>AG (p.Arg173Glu), designated R167Q or R173Q mice, respectively, were generated and compared with the previously established T1/T2 mice with ~30% residual HMBS activity and the heterozygous AIP phenotype. Homozygous R173Q mice were embryonic lethal, while R167Q homozygous mice (R167Q+/+) had ~5% of normal HMBS activity, constitutively elevated plasma and urinary 5-aminolevulinic acid (ALA) and porphobilinogen (PBG), profound early-onset ataxia, delayed motor development and markedly impaired rotarod performance. Central nervous system (CNS) histology was grossly intact, but CNS myelination was delayed and overall myelin volume was decreased. Heme concentrations in liver and brain were similar to those of T1/T2 mice. Notably, ALA and PBG concentrations in the cerebral spinal fluid and CNS regions were markedly elevated in R167Q+/+ mice compared with T1/T2 mice. When the T1/T2 mice were administered phenobarbital, ALA and PBG markedly accumulated in their liver and plasma, but not in the CNS, indicating that ALA and PBG do not readily cross the blood-brain barrier. Taken together, these studies suggest that the severe HD-AIP neurological phenotype results from decreased myelination and the accumulation of locally produced neurotoxic porphyrin precursors within the CNS.

Stereotaxic Targeting of Alpha-Synuclein Pathology in Mouse Brain Using Preformed Fibrils.

The accumulation of intraneuronal inclusions containing misfolded alpha-synuclein (aSyn) within the central nervous system (CNS) is a common feature found in several neurodegenerative disorders including Parkinson's disease (PD). Emerging evidence indicates that aSyn amyloid fibrils, a configuration that is present within these characteristic inclusions, are capable of self-replicating by templating the conversion of endogenously expressed aSyn in neurons. Stereotaxic administration of synthetic α-synuclein preformed fibrils (PFFs) into the mouse brain has been shown to seed the formation of intracellular aSyn pathology reminiscent of Lewy body (LB) inclusions present in human PD and related synucleinopathies. Moreover, pathology can be targeted to specific CNS regions. This experimental approach provides a versatile platform for investigating PD-like LB pathology in vivo. We focus here on procedures for initiating aSyn inclusion formation at various regions of the mouse brain using computer-assisted motorized stereotaxic microinjection of aSyn PFFs and discuss appropriate strategies for controls and analysis.

Piggybac CD19 CAR T Cells Eradicate CNS Leukemia By Direct Delivery into Cerebral Ventricle of Xenograft Mice Model

[Introduction]Despite the improvement in the treatment for childhood acute lymphoblastic leukemia (ALL), a central nervous system (CNS) involvement is still a risk factor for mortality. Moreover, CNS-directed treatments can cause acute and late adverse complications. Therefore, more effective and less toxic treatment strategy for CNS-ALL is needed.Recent clinical trials show that the anti-CD19 chimeric antigen receptor T-cell (CAR-T) therapy have an excellent effect against refractory and relapsed ALL. In these trials, some clinical effect of systemic intravenous (i.v.) delivery of CAR-T cells against CNS-ALL were reported and these reports implied clinical possibility and necessity for optimization of CAR-T therapy against CNS-ALL.The superior effect of direct delivery of CAR-T cells into solid tumors has been published, and we and others have shown the feasibility of intrathecal (IT) donor lymphocyte infusion for CNS-ALL without severe adverse events (Yanagisawa et al, IJH 2016). These reports inspired us to apply direct CAR-T cells infusion into CNS as a new therapeutic approach against CNS-ALL. However, as the lethally neurotoxicity has been reported in CAR-T clinical trials, preclinical study is a crucial step for clinical use of IT administration of CD19 CAR-T cells.We have previously reported ALL patient-derived xenograft (PDX) model with CNS infiltration in NOD/SCID/γc Null (NOG) mouse (Kato et al, ASH 2010). With this model, we have revealed the unique characteristics of CNS infiltrated leukemic cells and proposed new strategy targeting the CNS-ALL (Kato et al, Blood, 2018).In this study, we established an isolated CNS-ALL xenograft model with the intra-cerebroventricular (i.c.v.) injection of ALL cells and tested the feasibility and safety of the i.c.v. delivery of CAR-T cells into this model.[Method]CD19 CAR-T cells were generated with the piggyBac transposon system from isolated PBMCs donated from a healthy volunteer and expanded in the presence of IL-7 and IL-15 (Morita et al, Mol Ther Methdos Clin Dev 2018). SUSR cells, BCR-ABL fusion gene positive pre-B ALL cells, were genetically engineered to express GFP-FFLuc (SUSRGFP/luc).2×105 SUSRGFP/luc cells were injected by i.c.v. into 8-10 weeks old male NOG mice. Seven days after injection, confirming that SUSRGFP/luc cells were detected by IVIS imaging system only in CNS region, 2×106 piggyBac CD19 CAR-T cells injected by i.c.v. (CAR-T i.c.v.) (n=6), or i.v via tail-vein (CAR-T i.v) (n=5). As control groups, non-transduced T-cells from the same donor (Mock-T i.c.v.) (n=5) or vehicle (Medium i.c.v.) (n=5) were injected by i.c.v. No treatment group (n=4) received no i.c.v. injection. ALL invasion was followed by IVIS imaging. To assess the safety, we serially measured body weight, rectal temperature and scores of clinical symptoms of each mouse every morning after treatment.[Results]All mice in the Medium i.c.v. and no treatment group died by day 45. Both in the CAR-T i.v. and i.c.v. group, all mice were alive at day 45. Regardless of the route of injection, CAR-T administration prolonged the survival period. IVIS imaging revealed that 3/5 mice both in Mock-T i.c.v. and CAR-T i.v group failed to eliminate CNS-ALL at day 40. On the other hand, CAR-T i.c.v. completely eradicated ALL in all mice. Histopathological and flowcytometry analysis at day 4 after treatment also showed decrease of ALL cells and expansion of human CD3 positive T-cells in CAR-T i.c.v. mouse.Regarding clinical symptoms, weight loss, decrease in rectal temperature and elevation of clinical scores were observed only in SUSR transplanted CAR-T i.c.v. group during a few days after treatment. These changes were transient and not fatal. No neurological symptoms were observed in all mice. Histopathological analysis of CNS at day 4 showed slightly thickened epithelium of choroid plexus and edema localized around the lateral ventricle only in CAR-T i.c.v. mouse. Any other abnormalities associated neurotoxicity was not detected.[Discussion]In this preclinical study, we demonstrated that i.c.v. delivery of CD19 CAR-T cells had superior effect to i.v. delivery without any additional side effects. Our data suggests that IT administration of CD19 CAR-T cells would be an effective and feasible therapeutic approach against CNS-ALL. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Presentation Patterns and Management Strategies for Central Nervous System Involvement in Multiple Myeloma: A Systematic Review of Literature

Introduction:Central Nervous System (CNS) involvement in multiple myeloma (MM) is a rare extramedullary manifestation which occurs in less than 1% of MM cases. The median survival after the diagnosis (Dx) is 1-2 months (M). Literature review revealed us of various treatment modalities i.e. systemic chemotherapy (CT), intrathecal therapy (IT), and radiotherapy (RT). The primary aim of our analysis is to summarize published literature on presentation patterns and review effective management strategies regarding CNS involvement in MM and its outcome.Methods:We performed a systematic review of 2533 articles published from 2005 using five databases (PubMed, Embase, Cochrane Library, Web of Science and ClinicalTrials.gov). After a detailed screening, 28 studies were included.Results:A total of 550 patients (pts) data is included. Eighty-eight (16%) pts had CNS involvement at the time of their initial presentation and 462 (84%) pts had disease detected at the time of relapse / refractory (R/R) disease . The median reported follow up, from the time of initial Dx, was 18 months (M) [range (r) = 3.4-75M]. The median age of pts was 58 years (y) (r= 40-71). The clinical presentations were heterogeneous with cranial nerve palsy (21%), headache (17%), confusion (17%), visual disturbances (17%), extremity weakness (9%), cord symptoms (5%) and nausea / vomiting (5%). The CNS region involved was identified in 366 pts: 163 (44.5%) pts had leptomeningeal (LM) involvement, 98 (26.8%) pts had dural (D)/osteodural (OD) involvement, 10 (2.7%) pts had LM + D/OD involvement, 90 (24.6%) pts had intraparenchymal (IP) involvement and 5 (1.4%) pts had LM + IP involvement. Hundred twenty-nine pts had International Staging System (ISS) information availabe at the time of MM Dx, out of which 39 (30%) pts had stage I disease, 32 (25%) pts had stage II disease and 58(45%) pts had stage III disease. The median time ( reported in studies) for CNS involvement after MM Dx ranges from 2.5-122 M in pts who underwent systemic treatment and 7-96 M in patients who underwent stem cell transplant (SCT). Five hundred twelve (93%) pts underwent treatment, out of which 42 (8.2%) pts had IT therapy with methotrexate and/or cytarabine, 44 (8.5%) pts had RT, 170 (33.2%) pts had CT, 103 (20.1%) pts had IT + RT + CT, 77 (15%) pts had RT + CT, 16 (3.1%) pts had IT + RT and 60 (11.7%) pts had IT + CT. One hundred two pts had SCT along with the other therapies. Among the pts who received systemic treatment, 34 patients received therapy with conventional agents (CA), 80 patients received therapy with novel agents (NA), 347 patients were treated with combination therapy of CA and NA. Data regarding the rest 51 patients were not available. Bortezomib (V) based regimens were given in 158 pts; immune-modulators (IMiD) based regimens in 153 pts; vincristine, adriamycin, dexamethasone (VAd) regimen in 21 pts; alkylators in 85 pts; carfilzomib in 7 pts; bendamustine in 5 pts; pomalidomide in 5 pts and daratumumab was given in 2 pts. The mOS in patients who received NA therapy was 4-25 M. The mOS in patients who received CA therapy was 2.7-8 M. The mOS in patients who received both CA and NA was 2-7.4 M. Seventy-five out of 512 patients were evaluated for efficacy, out of which, 30 pts showed complete response (CR), 6 pts showed very good partial response (VGPR), 17 pts showed partial response (PR) and progressive disease (PD) was seen in 22 pts. Death was reported in 370 out of total 550 pts.Conclusion:Our analysis demonstrated that systemic CT with CA & NA, RT and IT therapy either alone or in combination are the currently available strategies employed in treating CNS myeloma. Furthermore, NA therapies have shown an increase in the overall survival i.e. up to 25 months. The IMiD have shown good CNS penetrance [thalidomide (30-40%), lenalidomide (11%) and pomalidomide (39-49%)] and effectiveness in the clearance of myeloma cells from CSF. There is no established standard of care for CNS myeloma. As prognosis remain dismal for such patients, newer innovative approaches need to be tested in clinical trials (use of drugs like thiotepa, IT Daratumomab, combination regimens for IT therapy coupled with CNS penetrating systemic therapy etc.) to improve current treatment outcomes. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Expression and Function of IL-33/ST2 Axis in the Central Nervous System Under Normal and Diseased Conditions.

Interleukin-33 (IL-33) is a well-recognized immunomodulatory cytokine which plays critical roles in tissue function and immune-mediated diseases. The abundant expression of IL-33 in brain and spinal cord prompted many scientists to explore its unique role in the central nervous system (CNS) under physiological and pathological conditions. Indeed emerging evidence from over a decade's research suggests that IL-33 acts as one of the key molecular signaling cues coordinating the network between the immune and CNS systems, particularly during the development of neurological diseases. Here, we highlight the recent advances in our knowledge regarding the distribution and cellular localization of IL-33 and its receptor ST2 in specific CNS regions, and more importantly the key roles IL-33/ST2 signaling pathway play in CNS function under normal and diseased conditions.

Kat2a and Kat2b Acetyltransferase Activity Regulates Craniofacial Cartilage and Bone Differentiation in Zebrafish and Mice.

Cranial neural crest cells undergo cellular growth, patterning, and differentiation within the branchial arches to form cartilage and bone, resulting in a precise pattern of skeletal elements forming the craniofacial skeleton. However, it is unclear how cranial neural crest cells are regulated to give rise to the different shapes and sizes of the bone and cartilage. Epigenetic regulators are good candidates to be involved in this regulation, since they can exert both broad as well as precise control on pattern formation. Here, we investigated the role of the histone acetyltransferases Kat2a and Kat2b in craniofacial development using TALEN/CRISPR/Cas9 mutagenesis in zebrafish and the Kat2ahat/hat (also called Gcn5) allele in mice. kat2a and kat2b are broadly expressed during embryogenesis within the central nervous system and craniofacial region. Single and double kat2a and kat2b zebrafish mutants have an overall shortening and hypoplastic nature of the cartilage elements and disruption of the posterior ceratobranchial cartilages, likely due to smaller domains of expression of both cartilage- and bone-specific markers, including sox9a and col2a1, and runx2a and runx2b, respectively. Similarly, in mice we observe defects in the craniofacial skeleton, including hypoplastic bone and cartilage and altered expression of Runx2 and cartilage markers (Sox9, Col2a1). In addition, we determined that following the loss of Kat2a activity, overall histone 3 lysine 9 (H3K9) acetylation, the main epigenetic target of Kat2a/Kat2b, was decreased. These results suggest that Kat2a and Kat2b are required for growth and differentiation of craniofacial cartilage and bone in both zebrafish and mice by regulating H3K9 acetylation.

Isolation and Culture of Embryonic Mouse Neural Stem Cells.

Neural stem cells (NSCs) are multipotent and can give rise to the three major cell types of the central nervous system (CNS). In vitro culture and expansion of NSCs provide a suitable source of cells for neuroscientists to study the function of neurons and glial cells along with their interactions. There are several reported techniques for the isolation of neural stem cells from adult or embryo mammalian brains. During the microsurgical operation to isolate NSCs from different regions of the embryonic CNS, it is very important to reduce the damage to the brain cells to obtain the highest ratio of live and expandable stem cells. A possible technique for stress reduction during isolation of these cells from the mouse embryo brain is the reduction of surgical time. Here, we demonstrate a developed technique for rapid isolation of these cells from the E13 mouse embryo ganglionic eminence. Surgical procedures include harvesting E13 mouse embryos from the uterus, cutting the frontal fontanelle of the embryo with a bent needle tip, extracting the brain from the skull, microdissection of the isolated brain to harvest the ganglionic eminence, dissociation of the harvested tissue in NSC medium to gain a single cell suspension, and finally plating cells in suspension culture to generate neurospheres.

Neuroprotective and antihyperalgesic effects of orexin-A in rats with painful diabetic neuropathy

Aim of studyDiabetes mellitus is related to the development of neuronal tissue injury in different peripheral and central nervous system regions. A common complication of diabetes is painful diabetic peripheral neuropathy (PDN). We have studied the neuroprotective and anti-nociceptive properties of neuropeptide orexin-A in an animal experimental model of diabetic neuropathy. MethodsAll experiments were carried out on male Wistar rats (220-250 g). Diabetes was induced by a single intraperitoneal injection of 55 mg/kg (i.p.) streptozotocin (STZ). Orexin-A was chronically administrated into the implanted intrathecal catheter (0.6, 2.5 and 5 nM/L, daily, 4 weeks). The tail-flick and rotarod treadmill tests were used to evaluate the nociceptive threshold and motor coordination of these diabetic rats, respectively. Cleaved caspase-3, Bax, Bcl2 and the Bax/Bcl-2 ratio, as the biochemical indicators of apoptosis, were investigated in the dorsal half of the lumbar spinal cord tissue by western blotting method. ResultsTreatment of the diabetic rats with orexin-A (5 nM/L) significantly attenuated the hyperalgesia and motor deficit in diabetic animals. Furthermore, orexin-A (5 nM/L) administration suppressed pro-apoptotic cleaved caspase-3 and Bax proteins. Also, orexin-A (5 nM/L) reduced the expression of Bax/Bcl-2 ratio in spinal cord dorsal half of rats with PDN. ConclusionsAltogether our data suggest that the orexin-A has anti-hyperalgesic and neuroprotective effects in rats with PDN. Cellular mechanisms underlying the observed effects may, at least partially, be related to reducing the neuronal apoptosis.

Visual Evoked Potentials as a Biomarker in Multiple Sclerosis and Associated Optic Neuritis

: ABSTRACT:: Multiple sclerosis (MS) is an inflammatory, degenerative disease of the central nervous system (CNS) characterized by progressive neurological decline over time. The need for better "biomarkers" to more precisely capture and track the effects of demyelination, remyelination, and associated neuroaxonal injury is a well-recognized challenge in the field of MS. To this end, visual evoked potentials (VEPs) have a role in assessing the extent of demyelination along the optic nerve, as a functionally eloquent CNS region. Moreover, VEPs testing can be used to predict the extent of recovery after optic neuritis (ON) and capture disabling effects of clinical and subclinical demyelination events in the afferent visual pathway. In this review, the evolving role of VEPs in the diagnosis of patients with ON and MS and the utility of VEPs testing in determining therapeutic benefits of emerging MS treatments is discussed.

Differences in brain regions of three mice strains identified by label-free micro-Raman

The analysis of different central nervous system regions is interesting and necessary as each one is involved in specific physiological processes and pathologies. On that matter, differences in the chemical composition between the same brain regions in different mice strains have been reported. In this sense, the development of a simple method for the identification of these regions depending on their chemical composition becomes relevant. Raman microspectroscopy, a non-destructive analytical chemical approach for biological samples, is a widely used method for qualitative, quantitative, and structural analysis in biochemical research. Ten brain structures in three different mice strains (Triple transgenic for Alzheimer Disease, 3xTgAD; Cluster 57 black 6, C57BL/6; and the Swiss strain, CD1) were analyzed, and variations among samples from several brain regions were found. Particularly, the pattern of signals from the hippocampus, the prefrontal and temporal cortices, the basal forebrain, the striatum, the cerebellum, and the hypothalamus was discernable. Interestingly, notable signals regarding non-peptide small neurotransmitters were observed, including those related to acetylcholine. These bands were present in the Raman spectra of the basal forebrain and prefrontal cortex in the three mice strains, consistent with the relative abundance of this neurotransmitter in those regions. However, signals with lower intensities appeared in the basal forebrain of C57BL/6 in comparison with the same tissue of the other two strains. In addition, the Raman intensity of bands assigned to catecholamines in the striatum was lower in the 3xTgAD than those from both CD1 and C57BL/6 mice strains. This approach, as well as the reported differences, has potential application for designing analysis on specific murine models of brain diseases.

Transcriptional Convergence of Oligodendrocyte Lineage Progenitors during Development

SummaryPdgfra+ oligodendrocyte precursor cells (OPCs) arise in distinct specification waves during embryogenesis in the central nervous system (CNS). It is unclear whether there is a correlation between these waves and different oligodendrocyte (OL) states at adult stages. Here, we present bulk and single-cell transcriptomics resources providing insights on how transitions between these states occur. We found that post-natal OPCs from brain and spinal cord present similar transcriptional signatures. Moreover, post-natal OPC progeny of E13.5 Pdgfra+ cells present electrophysiological and transcriptional profiles similar to OPCs derived from subsequent specification waves, indicating that Pdgfra+ pre-OPCs rewire their transcriptional network during development. Single-cell RNA-seq and lineage tracing indicates that a subset of E13.5 Pdgfra+ cells originates cells of the pericyte lineage. Thus, our results indicate that embryonic Pdgfra+ cells in the CNS give rise to distinct post-natal cell lineages, including OPCs with convergent transcriptional profiles in different CNS regions.

BDNF haploinsufficiency exerts a transient and regionally different influence upon oligodendroglial lineage cells during postnatal development

Brain-Derived Neurotrophic Factor (BDNF) plays important roles in promoting myelination in the developing central nervous system (CNS), however the influence it exerts on oligodendrocyte development in vivo remains unclear. As BDNF knockout mice die in the perinatal period, we undertook a systematic developmental analysis of oligodendroglial lineage cells within multiple CNS regions of BDNF heterozygous (HET) mice. Our data identify that BDNF heterozygosity results in transient reductions in oligodendroglial lineage cell density and progression that are largely restricted to the optic nerve, whereas the corpus callosum, cerebral cortex, basal forebrain and spinal cord white matter tracts are unaffected. In the first two postnatal weeks, BDNF HET mice exhibit reductions in the density of oligodendroglial lineage cells, oligodendrocyte precursor cells (OPCs) and postmitotic oligodendrocytes selectively in the optic nerve, but not in the brain or spinal cord white matter tracts. However, this normalizes later in development. The overall proportion of OPCs and mature oligodendrocytes remains unchanged from P9 to P30 in all CNS regions. This study identifies that BDNF exerts transient effects on oligodendroglial lineage cells selectively in the optic nerve during postnatal development. Taken together, this provides compelling evidence that BDNF haploinsufficiency exerts modest effects upon oligodendroglial cell density and lineage progression in vivo, suggesting its major role is restricted to promoting oligodendrocyte myelination.

The Tenascin-C-Derived Peptide VSWRAPTA Promotes Neuronal Branching Via Transcellular Activation of the Focal Adhesion Kinase (FAK) and the ERK1/2 Signaling Pathway In Vitro.

The central nervous system (CNS) of mammals has a limited regeneration capacity after traumatic events, which causes chronic functional disability. The development of biomaterials aims at providing support for the regeneration process. One strategy integrates peptides that mimic functional domains of extracellular matrix (ECM) or cell adhesion molecules with synthetic polymers designed to present growth-supporting cues to the neuronal microenvironment. Thus, small peptide sequences originating from molecules of the ECM may serve as promising bio-additives, acting as artificial matricryptins to gear cellular processes. The glycoprotein tenascin-C (Tnc) is a major constituent of the ECM of the developing brain and persists in the neurogenic regions of the adult CNS. It is a multimodular glycoprotein that comprises distinct domains with neurite growth promoting and axon growth repulsing properties. In the present study, the novel peptide motif VSWRAPTA that is encoded in the neurite growth promoting 6th fibronectin type III repeat close to the alternative splice site of Tnc was tested for its effects on neuron differentiation. When this newly synthesized biomimetic peptide was added to cultures of embryonic cortical neurons it significantly promoted the outgrowth of neurites. The neuron differentiation supporting effect was thereby associated with the trans-cellular activation of the focal adhesion kinase (FAK) and the extracellular signal-regulated kinase 1/2 (ERK1/2) pathway. Cortical neurons supplemented with the Tnc peptide displayed a dose-dependent increase in neurite outgrowth that saturated at a peptide concentration of 50μg/ml (56.4mMol/l). The analysis of neuron morphology revealed that neurite branching rather than fiber length was stimulated by the Tnc peptide. Therefore, we predict that the analyzed peptide motif of the 6th constitutively expressed FNIII domain of the Tnc molecule might be a major contributor for neurite outgrowth and guiding events in the native CNS microenvironment. In conclusion, the Tnc-derived VSWRAPTA peptide may represent a promising tool to spike regeneration supportive microenvironments.

Physical Linkage of Estrogen Receptor α and Aromatase in Rat: Oligocrine and Endocrine Actions of CNS-Produced Estrogens

Rapid-signaling membrane estrogen receptors (mERs) and aromatase (Aro) are present throughout the central nervous system (CNS), enabling acute regulation of CNS estrogenic signaling. We previously reported that spinal membrane Aro (mAro) and mERα oligomerize (1). As their organizational relationship would likely influence functions of locally produced estrogens, we quantified the mAro and mERα that are physically associated and nonassociated in two functionally different regions of rat CNS: the spinal cord, which has predominantly neural functionalities, and the hypothalamus, which has both neural and endocrine capabilities. Quantitative immunoprecipitation (IP), coimmunoprecipitation, and Western blot analysis were used to quantify the associated and nonassociated subpopulations of mAro and mERα. Regardless of estrous-cycle stage, virtually all mAro was oligomerized with mERα in the spinal cord, whereas only ∼15% was oligomerized in the hypothalamus. The predominance of nonassociated mAro in the hypothalamus, in combination with findings that many hypothalamic Aro-immunoreactive neurons could be retrogradely labeled with peripherally injected Fluoro-Gold, suggests that a portion of hypothalamic estrogens is secreted, potentially regulating pituitary function. Moreover, circulating estrogens increased hypothalamic Aro activity (quantified by the tritiated water-release assay) in the absence of increased Aro protein, revealing nongenomic regulation of Aro activity in the mammalian CNS. The demonstrated presence of associated and nonassociated mAro and mERα subpopulations in the CNS suggests that their selective targeting could restore impaired estrogen-dependent CNS functionalities while minimizing unwanted effects. The full physiological ramifications of brain-secreted estrogens remain to be explored.

Neuroprotective and antinociceptive effects of rosemary (Rosmarinus officinalis L.) extract in rats with painful diabetic neuropathy.

Diabetes mellitus is associated with the development of neuronal tissue damage in different central and peripheral nervous system regions. A common complication of diabetes is painful diabetic peripheral neuropathy. We have explored the antihyperalgesic and neuroprotective properties of Rosmarinus officinalis L. extract (RE) in a rat model of streptozotocin (STZ)-induced diabetes. The nociceptive threshold and motor coordination of these diabetic rats was assessed using the tail-flick and rotarod treadmill tests, respectively. Activated caspase-3 and the Bax:Bcl-2 ratio, both biochemical indicators of apoptosis, were assessed in the dorsal half of the lumbar spinal cord tissue by western blotting. Treatment of the diabetic rats with RE improved hyperglycemia, hyperalgesia and motor deficit, suppressed caspase-3 activation and reduced the Bax:Bcl-2 ratio, suggesting that the RE has antihyperalgesic and neuroprotective effects in this rat model of STZ-induced diabetes. Cellular mechanisms underlying the observed effects may, at least partially, be related to the inhibition of neuronal apoptosis.

Circadian signaling in Homarus americanus: Region-specific de novo assembled transcriptomes show that both the brain and eyestalk ganglia possess the molecular components of a putative clock system

Essentially all organisms exhibit recurring patterns of physiology/behavior that oscillate with a period of ~24-h and are synchronized to the solar day. Crustaceans are no exception, with robust circadian rhythms having been documented in many members of this arthropod subphylum. However, little is known about the molecular underpinnings of their circadian rhythmicity. Moreover, the location of the crustacean central clock has not been firmly established, although both the brain and eyestalk ganglia have been hypothesized as loci. The American lobster, Homarus americanus, is known to exhibit multiple circadian rhythms, and immunodetection data suggest that its central clock is located within the eyestalk ganglia rather than in the brain. Here, brain- and eyestalk ganglia-specific transcriptomes were generated and used to assess the presence/absence of transcripts encoding the commonly recognized protein components of arthropod circadian signaling systems in these two regions of the lobster central nervous system. Transcripts encoding putative homologs of the core clock proteins clock, cryptochrome 2, cycle, period and timeless were found in both the brain and eyestalk ganglia assemblies, as were transcripts encoding similar complements of putative clock-associated, clock input pathway and clock output pathway proteins. The presence and identity of transcripts encoding core clock proteins in both regions were confirmed using PCR. These findings suggest that both the brain and eyestalk ganglia possess all of the molecular components needed for the establishment of a circadian signaling system. Whether the brain and eyestalk clocks are independent of one another or represent a single timekeeping system remains to be determined. Interestingly, while most of the proteins deduced from the identified transcripts are shared by both the brain and eyestalk ganglia, assembly-specific isoforms were also identified, e.g., several period variants, suggesting the possibility of region-specific variation in clock function, especially if the brain and eyestalk clocks represent independent oscillators.