Joint effect of the SMN2 and SERF1A genes on childhood-onset types of spinal muscular atrophy in Serbian patients.

Spinal muscular atrophy (SMA) is caused by functional loss of the survival of motor neuron 1 (SMN1) gene. Despite genetic homogeneity, phenotypic variability indicates the involvement of disease modifiers. SMN1 is located in 5q13.2 segmental duplication, enriched in genes and prone to unequal rearrangements, which results in copy number polymorphism (CNP). We examined the influence of CNP of 5q13.2 genes and their joint effect on childhood-onset SMA phenotype. Multiplex ligation-dependent probe amplification (MLPA) was used to construct 5q13.2 alleles and assess copy number of the SMN2, small EDRK-rich factor 1A (SERF1A) and NLR family apoptosis inhibitory protein (NAIP) genes in 99 Serbian patients with SMN1 homozygous absence (23-type I, 37-type II and 39-mild type III) and 122 patients' parents. Spearman rank test was performed to test correlation of individual genes and SMA type. Generalized linear models and backward selection were performed to obtain a model explaining phenotypic variation with the smallest set of variables. 5q13.2 alleles most commonly associated with type I harbored large-scale deletions, while those detected in types II and III originated from conversion of SMN1 to SMN2. Inverse correlation was observed between SMN2, SERF1A and NAIP CNP and SMA type (P=2.2e-16, P=4.264e-10, P=2.722e-8, respectively). The best minimal model describing phenotypic variability included SMN2 (P<2e-16), SERF1A (P<2e-16) and their interaction (P=0.02628). SMN2 and SERF1A have a joint modifying effect on childhood-onset SMA phenotype.

Effects of MK-886, a 5-lipoxygenase activating protein (FLAP) inhibitor, and 5-lipoxygenase deficiency on the forced swimming behavior of mice.

A common biological pathway may contribute to the comorbidity of atherosclerosis and depression. Increased activity of the enzymatic 5-lipoxygenase (5-LOX, 5LO) pathway is a contributing factor in atherosclerosis and a 5-LOX inhibitor, MK-886, is beneficial in animal models of atherosclerosis. In the brain, MK-886 increases phosphorylation of the glutamate receptor subunit GluR1, and the increased phosphorylation of this receptor has been associated with antidepressant treatment. In this work, we evaluated the behavioral effects of MK-886 in an automated assay of mouse forced swimming, which identifies antidepressant activity as increased climbing behavior and/or decreased rest time. Whereas a single injection of MK-886 (3 and 10 mg/kg) did not affect forced swimming behaviors assayed 30 min later, six daily injections of 3 mg/kg MK-886 slightly increased climbing and significantly reduced rest time in wild-type mice but not in 5-LOX-deficient mice. A diet delivery of MK-886, 4 micro/(100 mg(body-weight)day), required 3 weeks to affect forced swimming; it increased climbing behavior. Climbing behavior was also increased in naive 5-LOX-deficient mice compared to naive wild-type controls. These results suggest that 5-LOX inhibition and deficiency may be associated with antidepressant activity. Increased climbing in a forced swimming assay is a typical outcome of antidepressants that increase noradrenergic and dopaminergic activity. Interestingly, 5-LOX deficiency and MK-886 treatment have been shown to be capable of increasing the behavioral effects of a noradrenaline/dopamine-potentiating drug, cocaine. Future research is needed to evaluate the clinical relevance of our findings.

5-Lipoxygenase inhibitor MK-886 increases GluR1 phosphorylation in neuronal cultures in vitro and in the mouse cortex in vivo.

Modifications of AMPA glutamate receptor GluR1 phosphorylation are critical for neuroplastic mechanisms. Previous in vitro studies in brain slices employed MK-886, a functional inhibitor of the enzyme 5-lipoxygenase (5-LOX), and found increased GluR1 phosphorylation. Since slice preparations have accompanying postmortem phosphorylation changes, e.g., decreased GluR1 phosphorylation, it remains to be clarified whether MK-886 can affect GluR1 phosphorylation in intact neurons and in the brain in vivo. We used primary neuronal cultures prepared from embryonic mouse brain and in vivo drug administration to investigate the effects of MK-886 on GluR1 phosphorylation using quantitative Western immunoblotting assays. In vitro, MK-886 increased GluR1 phosphorylation at both serine 831 and serine 845. In vivo, repeated but not a single MK-886 injection increased GluR1 phosphorylation in the prefrontal cortex. These findings indicate that MK-886 has an intrinsic effect on neuronal phosphorylation both in vitro and in vivo and support the use of MK-886 as a pharmacological tool in studies of not only the 5-LOX pathway but also neuronal GluR1 functioning.

Techniques: fruit flies as models for neuropharmacological research.

An unlikely animal model is gaining popularity in neuropharmacological research: the 2-mm fruit fly (Drosophila melanogaster). Drugs have been administered to adult flies in their food and, more recently, via gasses and injections. Pharmacological tools have introduced behavioral alterations in Drosophila reminiscent of human behavior, rescued flies from gene-alteration-triggered neuropathologies, and triggered gene silencing. Combined, these methods hold promise for significant neuropharmacological advancement.

Reliability assessment of an automated forced swim test device using two mouse strains.

The Porsolt forced swim test (FST) is one of the most widely used behavioral tests in the evaluation of the antidepressant effects of drugs. It is based on the fact that these drugs reduce the depression-related behaviors of learned helplessness. The model has been modified for use in mice. In contrast to rats, mice are exposed to forced swimming only once and their immobility behavior is measured and considered a "depression-like" phenotype. Like many other behavioral tests, FST can be affected by observer-related artifacts. In recent years, automated testing systems have been developed to decrease artifacts that may greatly influence the interpretation of results. In this work, we used two strains of mice, i.e., C3H/HeJ and C57BL/6J, which differ in their FST immobility times. We employed a new commercially available automated FST device and a blinded observer-based FST, and we examined their ability to measure behavioral differences between these two mouse strains. Our results suggest that the tested automated FST system generates reliable data comparable to results obtained by trained observers.

Drosophila GABA(B) receptors are involved in behavioral effects of gamma-hydroxybutyric acid (GHB).

Gamma-hydroxybutyric acid (GHB) can be synthesized in the brain but is also a known drug of abuse. Although putative GHB receptors have been cloned, it has been proposed that, similar to the behavior-impairing effects of ethanol, the in vivo effects of pharmacological GHB may involve metabotropic gamma-aminobutyric acid (GABA) GABA(B) receptors. We developed a fruitfly (Drosophila melanogater) model to investigate the role of these receptors in the behavioral effects of exogenous GHB. Injecting GHB into male flies produced a dose-dependent motor impairment (measured with a computer-assisted automated system), which was greater in ethanol-sensitive cheapdate mutants than in wild-type flies. These effects of pharmacological concentrations of GHB require the presence and activation of GABA(B) receptors. The evidence for this was obtained by pharmacological antagonism of GABA(B) receptors with CGP54626 and by RNA interference (RNAi)-induced knockdown of the GABA(B(1)) receptor subtype. Both procedures inhibited the behavioral effects of GHB. GHB pretreatment diminished the behavioral response to subsequent GHB injections; i.e., it triggered GHB tolerance, but did not produce ethanol tolerance. On the other hand, ethanol pretreatment produced both ethanol and GHB tolerance. It appears that in spite of many similarities between ethanol and GHB, the primary sites of their action may differ and that recently cloned putative GHB receptors may participate in actions of GHB that are not mediated by GABA(B) receptors. These receptors do not have a Drosophila orthologue. Whether Drosophila express a different GHB receptor should be explored.

Developmental role of GABAB(1) receptors in Drosophila.

Previously, an RNA interference (RNAi) knockdown of GABAB(1) subunit in adult Drosophila was used for behavioral studies. Here we report on developmental deficits caused by embryonic Drosophila GABAB(1) RNAi and drug antagonism. Injecting embryos with CGP54626 (a GABAB receptor antagonist) reduced hatching and caused lethality. Similar effects were produced by injecting embryos with GABAB(1) double-stranded RNA (RNAi). The surviving GABAB(1) RNAi larvae were significantly smaller than controls and showed a peculiar phenotype; their tracheae were folded. Our results suggest that GABAB receptors are required for normal development and that the Drosophila model could be used to investigate the participating molecular mechanisms.

Fruit flies for anti-pain drug discovery.

Recent work has indicated that fruit flies (Drosophila melanogaster) can be used in nociception research. Genetic screening identified a gene, painless, that is required for thermal and mechanical nociception in Drosophila larvae. On the other hand, pharmacological techniques and noxious heat were used to assay antinocieceptive behavior in intact adult Drosophila. In general, animal models for pain research are bound by ethical concerns. Since no serious ethical controversies have been raised regarding experiments in insects, Drosophila may be, for the time being an ethically acceptable animal model for combined genetic and pharmacological analgesia research.

Subtelomeric screening in Serbian children with dysmorphic features and unexplained developmental delay/intellectual disabilities.

Developmental delay and intellectual disabilities (DD/ID) are significant health problems affecting 3% of the human population. Submicroscopic chromosomal rearrangements involving subtelomeric regions are often considered to be the cause of unexplained DD/ID. Screening of subtelomeric regions was performed in 80 unrelated patients with DD/ID and normal GTG-banded chromosomes using the MLPA method with two kits (SALSA P070-B1 and P036-E1). The MLPA screening revealed subtelomeric chromosome aberrations in four cases (5%). The aberrations detected were: 1p deletion, 1p deletion combined with 12q duplication, 4p deletion, and 9p deletion combined with 15q duplication. The deletions detected were classified as causative for the patients' observed phenotypes. This study confirms the high frequency of subtelomeric rearrangements in unexplained DD/ID and reinforces the argument for routine subtelomeric screening in order to get a correct diagnosis, establish genotype-phenotype correlations and offer accurate genetic counseling.

Identification of a novel Drosophila gene, beltless, using injectable embryonic and adult RNA interference (RNAi).

BACKGROUND: RNA interference (RNAi) is a process triggered by a double-stranded RNA that leads to targeted down-regulation/silencing of gene expression and can be used for functional genomics; i.e. loss-of-function studies. Here we report on the use of RNAi in the identification of a developmentally important novel Drosophila (fruit fly) gene (corresponding to a putative gene CG5652/GM06434), that we named beltless based on an embryonic loss-of-function phenotype. RESULTS: Beltless mRNA is expressed in all developmental stages except in 0-6 h embryos. In situ RT-PCR localized beltless mRNA in the ventral cord and brain of late stage embryos and in the nervous system, ovaries, and the accessory glands of adult flies. RNAi was induced by injection of short (22 bp) beltless double-stranded RNAs into embryos or into adult flies. Embryonic RNAi altered cuticular phenotypes ranging from partially-formed to missing denticle belts (thus beltless) of the abdominal segments A2-A4. Embryonic beltless RNAi was lethal. Adult RNAi resulted in the shrinkage of the ovaries by half and reduced the number of eggs laid. We also examined Df(1)RK4 flies in which deletion removes 16 genes, including beltless. In some embryos, we observed cuticular abnormalities similar to our findings with beltless RNAi. After differentiating Df(1)RK4 embryos into those with visible denticle belts and those missing denticle belts, we assayed the presence of beltless mRNA; no beltless mRNA was detectable in embryos with missing denticle belts. CONCLUSIONS: We have identified a developmentally important novel Drosophila gene, beltless, which has been characterized in loss-of-function studies using RNA interference. The putative beltless protein shares homologies with the C. elegans nose resistant to fluoxetine (NRF) NRF-6 gene, as well as with several uncharacterized C. elegans and Drosophila melanogaster genes, some with prominent acyltransferase domains. Future studies should elucidate the role and mechanism of action of beltless during Drosophila development and in adults, including in the adult nervous system.

5-lipoxygenase (5LOX)-deficient mice express reduced anxiety-like behavior.

PURPOSE: 5-Lipoxygenase (5LOX) is an enzyme critical for leukotriene synthesis from arachidonic acid. In addition to its role in peripheral inflammation, this enzyme is also expressed in the brain but its functional role in the central nervous system is poorly understood. An upregulated expression of brain 5LOX, for example during aging and in multiple sclerosis, has been associated with increased vulnerability to neurodegeneration. Moreover, the 5LOX pathway has been associated with the neurotoxicity of the prion peptide. 5LOX-deficient mice [5LOX(-); B6129S(Alox5tm1Fun)] and their controls (B6129SF2/J) have not been behaviorally characterized. METHODS: The following behavioral tests were used for behavioral characterization of 5LOX(-) mice: elevated plus-maze, marble burying, locomotor activity, rota-road, and the spontaneous alternations in T-maze. RESULTS: We found that in an elevated plus-maze, 5LOX(-) mice spent a shorter time in the "safe" closed arms, a longer time in the "anxiogenic" open arms, and entered the open arms more frequently. They also covered fewer marbles in the marble-burying anxiety test. No difference was observed between 5LOX(-) and 5LOX(+) mice in other tests. CONCLUSION: These results indicate that 5LOX(-) mice are less prone to anxiety and point to a possible role for 5LOX in affective behaviors. We propose that creating congenic 5LOX(-) mice by backcrossing into inbred strains would provide additional tools to further elucidate this putative role.

The pineal gland and anxiogenic-like action of fluoxetine in mice.

Fluoxetine produces initial paradoxical anxiogenic effect in some patients. In an elevated plus-maze (EPM), fluoxetine triggers an anxiogenic-like effect in rodents. Behavioral responses to psychoactive drugs can be modified by the pineal gland. We assessed the actions of fluoxetine in the EPM in melatonin-proficient C3H mice, melatonin-deficient C57BL6 mice, and in sham-operated and pinealectomized mice. Mice were assayed 30 min after the first injection and on day 14. Protracted fluoxetine treatment reduced the time on the anxiogenic open arms and increased the entries into the safe closed arms in sham-operated C3H mice. Fluoxetine was ineffective in pinealectomized C3H or C57BL6 mice. It is possible that the pineal system contributes to the previously observed anxiogenic action of fluoxetine in humans.

An automated assay of the behavioral effects of cocaine injections in adult Drosophila.

Introducing Drosophila models in neuropharmacological research helps to discover new mechanisms of drug action. In fruit flies, the pharmacobehavioral approach has been used to evaluate the effects of drugs of abuse including cocaine. Standard procedures of cocaine administration to flies employ drug vaporization whereas behavior is evaluated either by trained observers or by videotaping followed by analysis via a computer-operated tracking system. Because in mammalian studies cocaine is typically administered by injection, a procedure that ensures precise and timely dose delivery, we developed a method for injecting cocaine into adult Drosophila. To objectively measure the behavioral response of flies to cocaine injections, we adapted the standard Drosophila Activity Monitoring System (Trikinetics). We found that in wild-type Canton S flies, cocaine injections produce a dose-dependent increase in the number of hyperactivity bursts and that repeated injections of cocaine produce behavioral sensitization. Acute responses to cocaine were observed also in period null (per(0)) mutant flies, but in these flies, repeated injections of cocaine did not produce sensitization. In conclusion, we developed a method for accurately measuring the behavioral effects of cocaine in adult fruit flies that can be applied to studies of the mechanisms of behavioral sensitization.

Drosophila model for in vivo pharmacological analgesia research.

Fruit flies (Drosophila melanogaster) are typically used for genetic studies but they also could be employed for neuropharmacological research. Therefore, we designed an apparatus and developed methods to investigate how injecting antinociceptive drugs, i.e., a gamma-aminobutyric acid B receptor agonist, to adult flies affects their avoidance of noxious heat stimuli. We found a drug-induced dose-dependent increased threshold for heat avoidance and we propose Drosophila as an ethically acceptable animal model for in vivo pharmacological analgesia research.

Drosophila metabolize 1,4-butanediol into gamma-hydroxybutyric acid in vivo.

A solvent, 1,4-butanediol, is also abused as a recreational drug. In mammals, 1,4-butanediol is metabolized into gamma-hydroxybutyric acid (GHB), which stimulates metabotropic gamma-aminobutyric acid (GABA) GABAB and putative GHB receptors. Here we show that in vivo injection of 1,4-butanediol into adult Drosophila leads to GHB synthesis (GHB was detectable 5 min after 1,4-butanediol injection and increased dramatically 1-2 h later). This synthesis of GHB was accompanied by an impairment of locomotor activity that was mimicked by a direct injection of GHB into flies. We propose Drosophila as a model to study the molecular actions of 1,4-butanediol and GHB.

Early presentation of neuromyelitis optica.

Neuromyelitis optica is a rare autoimmune demyelinating disease of the central nervous system in childhood. Its relapsing form is usually reported in adults. We report a 3-year-old girl with relapsing, IgG seropositive neuromyelitis optica. Initially she presented with optic neuritis, followed by three relapses with deterioration of optic neuritis and developing transverse myelitis. With each relapse, the treatment was less effective. Four years after the onset of the disease, the patient was blind, had paraplegia associated with urinary and bowel incontinence and short stature.

[Evaluation of psycho-motor development in children with West syndrome].

INTRODUCTION: West Syndrome (WS) is age-related epileptic encephalopathy characterised by a triad of symptoms: specific seizure type, pathognomonic electroencephalographic (EEG) pattern--hypsarrhythmia and delay and/or regression in psychomotor development (PMD). Aetiologically, it occurs in three forms: symptomatic, cryptogenic and idiopathic. OBJECTIVE: Estimation of PMD in children with WS according to aetiology. METHODS: The observed group consisted of 65 children. Age range was between 6 and 30 months. The patients were divided into three groups according to aetiology. All patients underwent psychological examination with Brunet-Lesine test, as well as PMD evaluation based on achieved developmental milestones for the corresponding age. RESULTS: Statistically significant better values in the Human Developmental Index (HDI) had patients with idiopathic compared to otherforms of WS, at testing after 12 months (93.0 +/- 8.1 vs. 46.8 +/- 6.1 vs. 45.6 +/- 3.8), as well as after 24 months (93.9 +/- 7.7 vs. 51.9 +/- 5.5 vs. 50.9 +/- 4.4). The best values of HDI after 24 months had patients with improvement in PMD with the average of 66.2 +/- 4.4, which was statistically significant compared to those with unchanged PMD (41.5 +/- 5.3) and with further regression in PMD (28.3 +/- 4.4). Significant correlation was obtained between PMD after 12 and 24 months (r = 0.477), as well as a considerable improvement in HDI from the 12th to 24th month (49.4 +/- 4.0 vs. 53.7 +/- 3.9). CONCLUSION: The patients with idiopathic WS accomplished the best PMD. Improvement in PMD after 12 and 24 months of treatment was associated with improved HDI. Improvement in PMD was observed in all patients after 2 years of follow-up.

Epilepsy in a child with Wolf-Hirschhorn syndrome.

INTRODUCTION: Wolf-Hirschhorn syndrome (WHS) is a rare chromosomal disorder characterized by facial dismorphy, multiple congenital anomalies, delayed psychomotor development and pharmaco-resistant epilepsy. CASE OUTLINE: We present a 5-year-old girl with severe delay in growth and development, microcephaly, mild facial dismorphy and epilepsy. The pregnancy was complicated by intrauterine growth retardation. Generalized muscle hypotonia was observed at birth. First seizures started at age of 9 months as unilateral convulsive status epilepticus (SE), sometimes with bilateral generalization. Seizures were often triggered by fever and were resistant to antiepileptic treatment. Introduction of lamotrigine and valproate therapy led to complete seizure control at the age of 33 months. Electroencephalographic (EEG) finding was typical at the beginning. After transitory improvement between age four and five years, epileptiform EEG activity appeared again at the age of five years, without observed clinical seizures. Magnetic resonance imaging showed diffuse brain atrophy and delay in myelination. Using Multiplex ligation-dependent probe amplification (MLPA) method, we disclosed heterozygote microdeletation of the distal part of the short arm of chromosome 4 (4p16). CONCLUSION: We present a clinical course of epilepsy in a patient with Wolf-Hirschhorn syndrome. The diagnosis was verified by modern molecular technique. This is the first molecular characterization of a patient with WHS performed in our country.

Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis: the first four patients in Serbia.

INTRODUCTION: Familial hypomagnesaemia with hypercalciuria and nephrocalcinosis (FHHNC) is a rare autosomal recessive disease characterized by excessive renal magnesium and calcium wasting, bilateral nehrocalcinosis and progressive renal failure. This is the first report of FHHNC of four patients in Serbia. OUTLINE OF CASES: The first three patients were siblings from the same family. The index case, a 9-year-old girl, presented with severe growth retardation, polyuria and polydipsia, while her brothers, 11 and 7 years old, were disclosed during family member screening. The father had a urolithiasis when aged 18 years, while intermittent microhaematuria and bilateral microlithiasis persisted later on. The fourth patient, a 16-year-old boy with sporadic FHHNC was discovered to have increased proteinuria at routine examination of urine before registration for secondary school. He was well grown up, normotensive, but had moderate renal failure (CKD 3 stage), mild hypomagnesaemia and severe hypercalciuria and nephrocalcinosis. Beside typical clinical and biochemical data, the diagnosis of FHHNC was confirmed by mutation analysis of the CLDN16 gene; in all four affected individuals a homozygous CLDN16 mutation (Leu151Phe) was found. Treatment with magnesium supplementation resulted in the normalization of serum magnesium levels only in one patient (patient 4), but hypercalciuria persisted and renal failure progressed in all patients. CONCLUSION: FHHNC is a rare cause of chronic renal failure. The first four patients with FHHNC in Serbia have been here described. The diagnosis of FHNNC based on the findings of nephrocalcinosis with hypomagnesiaemia and hypercalciuria, was confirmed by homozygous paracellin1-mutation exhibiting a Leu151Phe.

Erythrocytic transglutaminase inhibition hemolysis at presentation of celiac disease.

Celiac disease (CD) is a common autoimmune condition. Previously it was considered to be a rare childhood disorder, but is actually considered a relatively common condition, present at any age, which may have multiple complications and manifestations. Hematological disorders of the disease are not uncommon. Among these disorders, the most frequently reported are anemias as a result of iron deficiency, often associated with folate and/or B12 deficiency. Anemias caused by hemolysis are very rarely reported in celiac patients. An 11-year-old girl with a previous uneventful medical history presented with severe hemolytic anemia. Hemolysis was Coombs negative, accompanied by inappropriate low reticulocyte count, despite exaggerated bone marrow hyperplasia of the erythroid precursors which showed normal maturation. Serology for recent infections, including Epstein-Barr virus, parvovirus B19, cytomegalovirus and mycoplasma, were all negative. Levels of serum IgA, IgG and IgM, were all within normal ranges for age. Screening for anti-DNA, antinuclear, antineutrophil cytoplasmic, antimicrosomal, antithyroglobulin, and antimitochondrial antibodies and lupus anticoagulants, was negative. She was also negative for human immunodeficiency virus. Conventional therapy with corticosteroids and intravenous immunoglobulin failed. CD was serendipitously discovered upon screening for anti-tissue transglutaminase autoantibodies. The disease was confirmed by biopsy of the small intestine mucosa. The patient recovered with gluten-free diet. A unique case of CD is presented. CD should be serologically screened in each patient with Coombs negative "immune" hemolytic anemia, particularly if accompanied by "reticulocytopenia". A new hemolytic mechanism and very speculative explanation for "reticulocytopenia" are discussed.