Light-Induced Activation of a Specific Type-5 Metabotropic Glutamate Receptor Antagonist in the Ventrobasal Thalamus Causes Analgesia in a Mouse Model of Breakthrough Cancer Pain.

Breakthrough cancer pain (BTcP) refers to a sudden and transient exacerbation of pain, which develops in patients treated with opioid analgesics. Fast-onset analgesia is required for the treatment of BTcP. Light-activated drugs offer a novel potential strategy for the rapid control of pain without the typical adverse effects of systemic analgesic drugs. mGlu5 metabotropic glutamate receptor antagonists display potent analgesic activity, and light-induced activation of one of these compounds (JF-NP-26) in the thalamus was found to induce analgesia in models of inflammatory and neuropathic pain. We used an established mouse model of BTcP based on the injection of cancer cells into the femur, followed, 16 days later, by systemic administration of morphine. BTcP was induced by injection of endothelin-1 (ET-1) into the tumor, 20 min after morphine administration. Mice were implanted with optic fibers delivering light in the visible spectrum (405 nm) in the thalamus or prelimbic cortex to locally activate systemically injected JF-NP-26. Light delivery in the thalamus caused rapid and substantial analgesia, and this effect was specific because light delivery in the prelimbic cortex did not relieve BTcP. This finding lays the groundwork for the use of optopharmacology in the treatment of BTcP.

Analgesia induced by the epigenetic drug, L-acetylcarnitine, outlasts the end of treatment in mouse models of chronic inflammatory and neuropathic pain.

Background L-acetylcarnitine, a drug marketed for the treatment of chronic pain, causes analgesia by epigenetically up-regulating type-2 metabotropic glutamate (mGlu2) receptors in the spinal cord. Because the epigenetic mechanisms are typically long-lasting, we hypothesized that analgesia could outlast the duration of L-acetylcarnitine treatment in models of inflammatory and neuropathic pain. Results A seven-day treatment with L-acetylcarnitine (100 mg/kg, once a day, i.p.) produced an antiallodynic effect in the complete Freund adjuvant mouse model of chronic inflammatory pain. L-Acetylcarnitine-induced analgesia persisted for at least 14 days after drug withdrawal. In contrast, the analgesic effect of pregabalin, amitryptiline, ceftriaxone, and N-acetylcysteine disappeared seven days after drug withdrawal. L-acetylcarnitine treatment enhanced mGlu2/3 receptor protein levels in the dorsal region of the spinal cord. This effect also persisted for two weeks after drug withdrawal and was associated with increased levels of acetylated histone H3 bound to the Grm2 gene promoter in the dorsal root ganglia. A long-lasting analgesic effect of L-acetylcarnitine was also observed in mice subjected to chronic constriction injury of the sciatic nerve. In these animals, a 14-day treatment with pregabalin, amitryptiline, tramadol, or L-acetylcarnitine produced a significant antiallodynic effect, with pregabalin displaying the greatest efficacy. In mice treated with pregabalin, tramadol or L-acetylcarnitine the analgesic effect was still visible 15 days after the end of drug treatment. However, only in mice treated with L-acetylcarnitine analgesia persisted 37 days after drug withdrawal. This effect was associated with an increase in mGlu2/3 receptor protein levels in the dorsal horns of the spinal cord. Conclusions Our findings suggest that L-acetylcarnitine has the unique property to cause a long-lasting analgesic effect that might reduce relapses in patients suffering from chronic pain.

N-Acetyl-cysteine causes analgesia by reinforcing the endogenous activation of type-2 metabotropic glutamate receptors.

BACKGROUND: Pharmacological activation of type-2 metabotropic glutamate receptors (mGlu2 receptors) causes analgesia in experimental models of inflammatory and neuropathic pain. Presynaptic mGlu2 receptors are activated by the glutamate released from astrocytes by means of the cystine/glutamate antiporter (System x(c)(-) or Sx(c)(-)). We examined the analgesic activity of the Sx(c)(-) activator, N-acetyl-cysteine (NAC), in mice developing inflammatory or neuropathic pain. RESULTS: A single injection of NAC (100 mg/kg, i.p.) reduced nocifensive behavior in the second phase of the formalin test. NAC-induced analgesia was abrogated by the Sxc- inhibitor, sulphasalazine (8 mg/kg, i.p.) or by the mGlu2/3 receptor antagonist, LY341495 (1 mg/kg, i.p.). NAC still caused analgesia in mGlu3(-/-) mice, but was inactive in mGlu2(-/-) mice. In wild-type mice, NAC retained the analgesic activity in the formalin test when injected daily for 7 days, indicating the lack of tolerance. Both single and repeated injections of NAC also caused analgesia in the complete Freund's adjuvant (CFA) model of chronic inflammatory pain, and, again, analgesia was abolished by LY341495. Data obtained in mice developing neuropathic pain in response to chronic constriction injury (CCI) of the sciatic nerve were divergent. In this model, a single injection of NAC caused analgesia that was reversed by LY341495, whereas repeated injections of NAC were ineffective. Thus, tolerance to NAC-induced analgesia developed in the CCI model, but not in models of inflammatory pain. The CFA and CCI models differed with respect to the expression levels of xCT (the catalytic subunit of Sx(c)(-)) and activator of G-protein signaling type-3 (AGS3) in the dorsal portion of the lumbar spinal cord. CFA-treated mice showed no change in either protein, whereas CCI mice showed an ipislateral reduction in xCT levels and a bilateral increase in AGS3 levels in the spinal cord. CONCLUSIONS: These data demonstrate that pharmacological activation of Sxc- causes analgesia by reinforcing the endogenous activation of mGlu2 receptors. NAC has an excellent profile of safety and tolerability when clinically used as a mucolytic agent or in the management of acetaminophen overdose. Thus, our data encourage the use of NAC for the experimental treatment of inflammatory pain in humans.

The conditioned eyeblink reflex: a potential tool for the detection of cerebellar dysfunction in multiple sclerosis.

The delayed conditioned eyeblink reflex, in which an individual learns to close the eyelid in response to a conditioned stimulus (e.g. a tone) relies entirely on the functional integrity of a cerebellar motor circuitry that involves the contingent activation of Purkinje cells by parallel and climbing fibres. Molecular changes that disrupt the function of this circuitry, in particular a loss of type-1 metabotropic glutamate receptors (mGlu1 receptors), occur in Purkinje cells of patients with multiple sclerosis and in mice with experimental autoimmune encephalomyelitis as a result of neuroinflammation. mGlu1 receptors are required for cerebellar motor learning associated with the conditioned eyeblink reflex. We propose that the delayed paradigm of the eyeblink conditioning might be particularly valuable for the detection of subtle abnormalities of cerebellar motor learning that are clinically silent and are not associated with demyelinating lesions or axonal damage. In addition, the test might have predictive value following a clinically isolated syndrome, and might be helpful for the evaluation of the efficacy of drug treatment in multiple sclerosis.

Cardiac complications in a patient affected by systemic mastocytosis and primitive myelofibrosis: A case report.

Systemic mastocytosis with associated primitive myelofibrosis is a rare and complex disease with a difficult therapeutic management. The release of several inflammation mediators can trigger acute cardiovascular events.

Perineuronal nets are under the control of type-5 metabotropic glutamate receptors in the developing somatosensory cortex.

mGlu5 metabotropic glutamate receptors are highly functional in the early postnatal life, and regulate developmental plasticity of parvalbumin-positive (PV+) interneurons in the cerebral cortex. PV+ cells are enwrapped by perineuronal nets (PNNs) at the closure of critical windows of cortical plasticity. Changes in PNNs have been associated with neurodevelopmental disorders. We found that the number of Wisteria Fluoribunda Agglutinin (WFA)+ PNNs and the density of WFA+/PV+ cells were largely increased in the somatosensory cortex of mGlu5-/- mice at PND16. An increased WFA+ PNN density was also observed after pharmacological blockade of mGlu5 receptors in the first two postnatal weeks. The number of WFA+ PNNs in mGlu5-/- mice was close to a plateau at PND16, whereas continued to increase in wild-type mice, and there was no difference between the two genotypes at PND21 and PND60. mGlu5-/- mice at PND16 showed increases in the transcripts of genes involved in PNN formation and a reduced expression and activity of type-9 matrix metalloproteinase in the somatosensory cortex suggesting that mGlu5 receptors control both PNN formation and degradation. Finally, unilateral whisker stimulation from PND9 to PND16 enhanced WFA+ PNN density in the contralateral somatosensory cortex only in mGlu5+/+ mice, whereas whisker trimming from PND9 to PND16 reduced WFA+ PNN density exclusively in mGlu5-/- mice, suggesting that mGlu5 receptors shape the PNN response to sensory experience. These findings disclose a novel undescribed mechanism of PNN regulation, and lay the groundwork for the study of mGlu5 receptors and PNNs in neurodevelopmental disorders.

Enhanced tau phosphorylation in the hippocampus of mice treated with 3,4-methylenedioxymethamphetamine ("Ecstasy").

3,4-Methylenedioxymethamphetamine (MDMA) ("Ecstasy") produces neurotoxic effects, which result into an impairment of learning and memory and other neurological dysfunctions. We examined whether MDMA induces increases in tau protein phosphorylation, which are typically associated with Alzheimer's disease and other chronic neurodegenerative disorders. We injected mice with MDMA at cumulative doses of 10-50 mg/kg intraperitoneally, which are approximately equivalent to doses generally consumed by humans. MDMA enhanced the formation of reactive oxygen species and induced reactive gliosis in the hippocampus, without histological evidence of neuronal loss. An acute or 6 d treatment with MDMA increased tau protein phosphorylation in the hippocampus, revealed by both anti-phospho(Ser(404))-tau and paired helical filament-1 antibodies. This increase was restricted to the CA2/CA3 subfields and lasted 1 and 7 d after acute and repeated MDMA treatment, respectively. Tau protein was phosphorylated as a result of two nonredundant mechanisms: (1) inhibition of the canonical Wnt (wingless-type MMTV integration site family) pathway, with ensuing activation of glycogen synthase kinase-3beta; and (2) activation of type-5 cyclin-dependent kinase (Cdk5). MDMA induced the expression of the Wnt antagonist, Dickkopf-1, and the expression of the Cdk5-activating protein, p25. In addition, the increase in tau phosphorylation was attenuated by strategies that rescued the Wnt pathway or inhibited Cdk5. Finally, an impairment in hippocampus-dependent spatial learning was induced by doses of MDMA that increased tau phosphorylation, although the impairment outlasted this biochemical event. We conclude that tau hyperphosphorylation in the hippocampus may contribute to the impairment of learning and memory associated with MDMA abuse.

REN: a novel, developmentally regulated gene that promotes neural cell differentiation.

Expansion and fate choice of pluripotent stem cells along the neuroectodermal lineage is regulated by a number of signals, including EGF, retinoic acid, and NGF, which also control the proliferation and differentiation of central nervous system (CNS) and peripheral nervous system (PNS) neural progenitor cells. We report here the identification of a novel gene, REN, upregulated by neurogenic signals (retinoic acid, EGF, and NGF) in pluripotent embryonal stem (ES) cells and neural progenitor cell lines in association with neurotypic differentiation. Consistent with a role in neural promotion, REN overexpression induced neuronal differentiation as well as growth arrest and p27Kip1 expression in CNS and PNS neural progenitor cell lines, and its inhibition impaired retinoic acid induction of neurogenin-1 and NeuroD expression. REN expression is developmentally regulated, initially detected in the neural fold epithelium of the mouse embryo during gastrulation, and subsequently throughout the ventral neural tube, the outer layer of the ventricular encephalic neuroepithelium and in neural crest derivatives including dorsal root ganglia. We propose that REN represents a novel component of the neurogenic signaling cascade induced by retinoic acid, EGF, and NGF, and is both a marker and a regulator of neuronal differentiation.

GD3 nuclear localization after apoptosis induction in HUT-78 cells.

Glycosphingolipids are essential components of plasma membrane and act as antigens, mediators of cell adhesion, and modulators of signal transduction. Following activation of the Fas receptor, gangliosides are recuited in various intracellular compartments. We have evaluated whether the pro-apoptotic anti-CD95 antibody induces a nuclear localization of GD3 in HUT-78 cells. Our data shows that GD3 translocation from cytosol to nuclei is strongly correlated to concomitant rapid phosphorylation of histone H1 shortly after induction of apoptosis. This work advances the hypothesis that GD3 induces a post-translational modification of histone H1 thus influencing the apoptosis process through transcriptional activation/repression of specific genes.

Rusty Microglia: Trainers of Innate Immunity in Alzheimer's Disease.

Alzheimer's disease, the most common form of dementia, is marked by progressive cognitive and functional impairment believed to reflect synaptic and neuronal loss. Recent preclinical data suggests that lipopolysaccharide (LPS)-activated microglia may contribute to the elimination of viable neurons and synapses by promoting a neurotoxic astrocytic phenotype, defined as A1. The innate immune cells, including microglia and astrocytes, can either facilitate or inhibit neuroinflammation in response to peripherally applied inflammatory stimuli, such as LPS. Depending on previous antigen encounters, these cells can assume activated (trained) or silenced (tolerized) phenotypes, augmenting or lowering inflammation. Iron, reactive oxygen species (ROS), and LPS, the cell wall component of gram-negative bacteria, are microglial activators, but only the latter can trigger immune tolerization. In Alzheimer's disease, tolerization may be impaired as elevated LPS levels, reported in this condition, fail to lower neuroinflammation. Iron is closely linked to immunity as it plays a key role in immune cells proliferation and maturation, but it is also indispensable to pathogens and malignancies which compete for its capture. Danger signals, including LPS, induce intracellular iron sequestration in innate immune cells to withhold it from pathogens. However, excess cytosolic iron increases the risk of inflammasomes' activation, microglial training and neuroinflammation. Moreover, it was suggested that free iron can awaken the dormant central nervous system (CNS) LPS-shedding microbes, engendering prolonged neuroinflammation that may override immune tolerization, triggering autoimmunity. In this review, we focus on iron-related innate immune pathology in Alzheimer's disease and discuss potential immunotherapeutic agents for microglial de-escalation along with possible delivery vehicles for these compounds.

mGlu1 Receptors Monopolize the Synaptic Control of Cerebellar Purkinje Cells by Epigenetically Down-Regulating mGlu5 Receptors.

In cerebellar Purkinje cells (PCs) type-1 metabotropic glutamate (mGlu1) receptors play a key role in motor learning and drive the refinement of synaptic innervation during postnatal development. The cognate mGlu5 receptor is absent in mature PCs and shows low expression levels in the adult cerebellar cortex. Here we found that mGlu5 receptors were heavily expressed by PCs in the early postnatal life, when mGlu1α receptors were barely detectable. The developmental decline of mGlu5 receptors coincided with the appearance of mGlu1α receptors in PCs, and both processes were associated with specular changes in CpG methylation in the corresponding gene promoters. It was the mGlu1 receptor that drove the elimination of mGlu5 receptors from PCs, as shown by data obtained with conditional mGlu1α receptor knockout mice and with targeted pharmacological treatments during critical developmental time windows. The suppressing activity of mGlu1 receptors on mGlu5 receptor was maintained in mature PCs, suggesting that expression of mGlu1α and mGlu5 receptors is mutually exclusive in PCs. These findings add complexity to the the finely tuned mechanisms that regulate PC biology during development and in the adult life and lay the groundwork for an in-depth analysis of the role played by mGlu5 receptors in PC maturation.

Metabotropic glutamate receptors: beyond the regulation of synaptic transmission.

Metabotropic glutamate (mGlu) receptors are G-protein coupled receptors activated by glutamate, the major excitatory neurotransmitter of the CNS. A growing body of evidence suggests that the function of mGlu receptors is not restricted to the regulation of synaptic transmission. mGlu receptors are expressed in a variety of peripheral cells, including inter alia hepatocytes, pancreatic cells, osteoblasts and immune cells. Within the immunological synapses, mGlu receptors expressed by T cells might contribute to the vast array of signals generated by the antigen-presenting cells. mGlu receptors are also found in embryonic and neural stem cells. This suggests their involvement in the pathophysiology of brain tumors, which likely originates from cancer stem cells similar to neural stem cells. Ligands of mGlu3 and mGlu4 receptors are potential candidates for the experimental treatment of malignant gliomas and medulloblastomas, respectively.

Expression of the K+/Cl- cotransporter, KCC2, in cerebellar Purkinje cells is regulated by group-I metabotropic glutamate receptors.

The neuronal K+/Cl- symporter, KCC2, shapes synaptic responses mediated by Cl--permeant GABAA receptors. Moving from the evidence that excitatory neurotransmission drives changes in KCC2 expression in cerebellar neurons, we studied the regulation of KCC2 expression by group-I metabotropic glutamate (mGlu) receptors in the cerebellum of adult mice. Mice lacking mGlu5 receptors showed a large reduction in cerebellar KCC2 protein levels and a loss of KCC2 immunoreactivity in Purkinje cells. Similar changes were seen in mice treated with the mGlu5 receptor antagonist, MPEP, whereas treatment with the mGlu5 receptor positive allosteric modulator (PAM), VU0360172, increased KCC2 expression. In contrast, pharmacological inhibition of mGlu1 receptors with JNJ16259685 enhanced cerebellar KCC2 protein levels and KCC2 immunoreactivity in Purkinje cells, whereas treatment with the mGlu1 receptor PAM, RO0711401, reduced KCC2 expression. To examine whether the reduction in KCC2 expression caused by the absence or the inhibition of mGlu5 receptors could affect GABAergic transmission, we performed electrophysiological and behavioral studies. Recording of extracellular action potentials in Purkinje cells showed that the inhibitory effect of the GABAA receptor agonist, muscimol, was lost in cerebellar slices prepared from mGlu5-/- mice or from mice treated systemically with MPEP, in line with the reduction in KCC2 expression. Similarly, motor impairment caused by the GABAA receptor PAM, diazepam, was attenuated in mice pre-treated with MPEP. These findings disclose a novel function of mGlu5 receptors in the cerebellum and suggest that mGlu5 receptor ligands might influence GABAergic transmission in the cerebellum and affect motor responses to GABA-mimetic drugs. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.

The α2δ Subunit and Absence Epilepsy: Beyond Calcium Channels?

BACKGROUND: Spike-wave discharges, underlying absence seizures, are generated within a cortico-thalamo-cortical network that involves the somatosensory cortex, the reticular thalamic nucleus, and the ventrobasal thalamic nuclei. Activation of T-type voltage-sensitive calcium channels (VSCCs) contributes to the pathological oscillatory activity of this network, and some of the first-line drugs used in the treatment of absence epilepsy inhibit T-type calcium channels. The α2δ subunit is a component of high voltage-activated VSCCs (i.e., L-, N-, P/Q-, and R channels) and studies carried out in heterologous expression systems suggest that it may also associate with T channels. The α2δ subunit is also targeted by thrombospondins, which regulate synaptogenesis in the central nervous system. OBJECTIVE: To discuss the potential role for the thrombospondin/α2δ axis in the pathophysiology of absence epilepsy. METHODS: We searched PubMed articles for the terms "absence epilepsy", "T-type voltage-sensitive calcium channels", "α2δ subunit", "ducky mice", "pregabalin", "gabapentin", "thrombospondins", and included papers focusing this Review's scope. RESULTS: We moved from the evidence that mice lacking the α2δ-2 subunit show absence seizures and α 2δ ligands (gabapentin and pregabalin) are detrimental in the treatment of absence epilepsy. This suggests that α2δ may be protective against absence epilepsy via a mechanism that does not involve T channels. We discuss the interaction between thrombospondins and α2δ and its potential relevance in the regulation of excitatory synaptic formation in the cortico-thalamo-cortical network. CONCLUSION: We speculate on the possibility that the thrombospondin/α2 δ axis is critical for the correct functioning of the cortico-thalamo-cortical network, and that abnormalities in this axis may play a role in the pathophysiology of absence epilepsy.

Huntingtin fragmentation and increased caspase 3, 8 and 9 activities in lymphoblasts with heterozygous and homozygous Huntington's disease mutation.

Huntington's disease (HD) is caused by mutated huntingtin (htt), a toxic protein ubiquitously expressed in nervous and non-nervous system tissues. Fragmentation of htt by caspases and further accumulation in cells of protein aggregates contribute to cell dysfunction and death. In the attempt to elucidate whether this mechanism depends on patients' genotype, we analysed the pattern of htt fragmentation, the caspase 3, 8 and 9 activities and their variation in lymphoblasts with heterozygous and homozygous CAG mutation and in controls. Cells homozygous for expanded mutation showed greater amount of mutated fragments than heterozygotes and controls, caspase 3, 8 and 9 activities greater in mutated than control cell lines, after cyanide treatment, the caspase 3 and 8 particularly increased in homozygotes. This data offers a biological explanation to the clinical in-patients evidence of mutation homozygosity associated with more severe phenotype.

Role of gangliosides in the association of ErbB2 with lipid rafts in mammary epithelial HC11 cells.

We analyzed the role of gangliosides in the association of the ErbB2 receptor tyrosine-kinase (RTK) with lipid rafts in mammary epithelial HC11 cells. Scanning confocal microscopy experiments revealed a strict ErbB2-GM3 colocalization in wild-type cells. In addition, analysis of membrane fractions obtained using a linear sucrose gradient showed that ErbB2, epidermal growth factor receptor (EGFR) and Shc-p66 (proteins correlated with the ErbB2 signal transduction pathway) were preferentially enriched in lipid rafts together with gangliosides. Blocking of endogenous ganglioside synthesis by (+/-)-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol hydrochloride ([D]-PDMP) induced a drastic cell-surface redistribution of ErbB2, EGFR and Shc-p66, within the Triton-soluble fractions, as revealed by linear sucrose-gradient analysis. This redistribution was partially reverted when exogenous GM3 was added to ganglioside-depleted HC11 cells. The results point out the key role of ganglioside GM3 in retaining ErbB2 and signal-transduction-correlated proteins in lipid rafts.

Context-dependent regulation of embryonic stem cell differentiation by mGlu4 metabotropic glutamate receptors.

The mGlu5 receptor is the only metabotropic glutamate receptor subtype expressed by mouse embryonic stem (ES) cells grown under non-differentiating conditions [Cappuccio, I., Spinanti, P. Porcellini, A., Desiderati, F., De Vita, T., Storto, M., Capobianco, L., Battaglia, G., Nicoletti, F., Melchiorri, D., 2005. Endogenous activation of mGlu5 metabotropic glutamate receptors supports self-renewal of cultured mouse embryonic stem cells. Neuropharmacology 1, 196-205]. We now report that ES cells differentiating into embryoid bodies (EBs) progressively lose mGlu5 receptors and begin to express mGlu4 receptors at both mRNA and proteinc level. A 4-day treatment of EBs with the mGlu4 receptor agonist, L-2-amino-4-phosphonobutanoate (L-AP4), increased mRNA levels of the mesoderm marker, brachyury and the endoderm marker, H19, and decreased the expression of the transcript for the primitive ectoderm marker, fibroblast-growth factor-5 (FGF-5). These effects were prevented by the mGlu4 receptor antagonists, alpha-methylserine-O-phosphate (MSOP). Plating of EBs for 4 days in vitro in ITSFn medium induced cell differentiation towards a neural lineage, as reflected by the expression of the intermediate filament protein, nestin, and the homeobox protein, Dlx-2. Pharmacological activation of mGlu4 receptors during cell incubation in ITSFn medium increased the expression of both neural markers. Similar results were obtained when neural differentiation was induced by exposure of EBs to retinoic acid. These data suggest that differentiation of cultured ES cells is associated with changes in the expression pattern of mGlu receptors and that activation of mGlu4 receptors affects cell differentiation in a context-dependent manner.

Sinonasal adenocarcinoma in a patient without exposure to risk factors Case report and review of the literature.

OBJECTIVE: Sinonasal adenocarcinoma is a tumor typically associated with exposure to occupational carcinogens. The International Agency for Research on Cancer (IARC) published several data in order to classify carcinogenic power of physical-chemical agents as far as sinonasal cancer is concerned. MATERIALS AND METHODS: We report a clinical case of sinonasal adenocarcinoma observed in an 84 years old patient, without clinical history of past exposure to carcinogens, smoke and alcohol. RESULTS AND CONCLUSIONS: A sinonasal adenocarcinoma in a patient without risk factors is extremely rare. It is very important to recognize this cancer at an early stage in order to give better survival rates to the patients. KEY WORDS: Carcinogens, Intestinal-type adenocarcinoma, Sinonasal cancer.

Beta-amyloid-induced synthesis of the ganglioside GD3 is a requisite for cell cycle reactivation and apoptosis in neurons.

We have shown that cortical neurons challenged with toxic concentrations of beta-amyloid peptide (betaAP) enter the S phase of the cell cycle before apoptotic death. Searching for a signaling molecule that lies at the border between cell proliferation and apoptotic death, we focused on the disialoganglioside GD3. Exposure of rat cultured cortical neurons to 25 microm betaAP(25-35) induced a substantial increase in the intracellular levels of GD3 after 4 hr, a time that precedes neuronal entry into S phase. GD3 levels decreased but still remained higher than in the control cultures after 16 hr of exposure to betaAP(25-35). Confocal microscopy analysis showed that the GD3 synthesized in response to betaAP colocalized with nuclear chromatin. The increase in GD3 was associated with a reduction of sphingomyelin (the main source of the ganglioside precursor ceramide) and with the induction of alpha-2,8-sialyltransferase (GD3 synthase), the enzyme that forms GD3 from the monosialoganglioside GM3. A causal relationship between GD3, cell-cycle activation, and apoptosis was demonstrated by treating the cultures with antisense oligonucleotides directed against GD3 synthase. This treatment, which reduced betaAP(25-35)-stimulated GD3 formation by approximately 50%, abolished the neuronal entry into the S phase and was protective against betaAP(25-35)-induced apoptosis.

Proteomic and epigenomic markers of sepsis-induced delirium (SID).

In elderly population sepsis is one of the leading causes of intensive care unit (ICU) admissions in the United States. Sepsis-induced delirium (SID) is the most frequent cause of delirium in ICU (Martin et al., 2010). Together delirium and SID represent under-recognized public health problems which place an increasing financial burden on the US health care system, currently estimated at 143-152 billion dollars per year (Leslie et al., 2008). The interest in SID was recently reignited as it was demonstrated that, contrary to prior beliefs, cognitive deficits induced by this condition may be irreversible and lead to dementia (Pandharipande et al., 2013; Brummel et al., 2014). Conversely, it is construed that diagnosing SID early or mitigating its full blown manifestations may preempt geriatric cognitive disorders. Biological markers specific for sepsis and SID would facilitate the development of potential therapies, monitor the disease process and at the same time enable elderly individuals to make better informed decisions regarding surgeries which may pose the risk of complications, including sepsis and delirium. This article proposes a battery of peripheral blood markers to be used for diagnostic and prognostic purposes in sepsis and SID. Though each individual marker may not be specific enough, we believe that together as a battery they may achieve the necessary accuracy to answer two important questions: who may be vulnerable to the development of sepsis, and who may develop SID and irreversible cognitive deficits following sepsis?