Ac-SDKP attenuates ER stress-stimulated collagen production in cardiac fibroblasts by inhibiting CHOP-mediated NF-κB expression

Inflammation and cardiac fibrosis are prevalent pathophysiologic conditions associated with hypertension, cardiac remodeling, and heart failure. Endoplasmic reticulum (ER) stress triggers the cells to activate unfolded protein responses (UPRs) and upregulate the ER stress chaperon, enzymes, and downstream transcription factors to restore normal ER function. The mechanisms that link ER stress-induced UPRs upregulation and NF-κB activation that results in cardiac inflammation and collagen production remain elusive. N-Acetyl-Ser-Asp-Lys-Pro (Ac-SDKP), a natural tetrapeptide that negatively regulates inflammation and fibrosis, has been reported. Whether it can inhibit ER stress-induced collagen production in cardiac fibroblasts remains unclear. Thus, we hypothesized that Ac-SDKP attenuates ER stress-stimulated collagen production in cardiac fibroblasts by inhibiting CHOP-mediated NF-κB expression. We aimed to study whether Ac-SDKP inhibits tunicamycin (TM)-induced ER stress signaling, NF-κB signaling, the release of inflammatory cytokine interleukin-6, and collagen production in human cardiac fibroblasts (HCFs). HCFs were pre-treated with Ac-SDKP (10 nM) and then stimulated with TM (0.25 μg/mL). We found that Ac-SDKP inhibits TM-induced collagen production by attenuating ER stress-induced UPRs upregulation and CHOP/NF-κB transcriptional signaling pathways. CHOP deletion by specific shRNA maintains the inhibitory effect of Ac-SDKP on NF-κB and type-1 collagen (Col-1) expression at both protein and mRNA levels. Attenuating ER stress-induced UPR sensor signaling by Ac-SDKP seems a promising therapeutic strategy to combat detrimental cardiac inflammation and fibrosis.

An early glycolysis burst in microglia regulates mitochondrial dysfunction in oligodendrocytes under neuroinflammation

Metabolism and energy processes governing oligodendrocyte function during neuroinflammatory disease are of great interest. However, how varied cellular environments affect oligodendrocyte activity during neuroinflammation is unknown. We demonstrate that activated microglial energy metabolism controls oligodendrocyte mitochondrial respiration and activity. Lipopolysaccharide/interferon gamma promote glycolysis and decrease mitochondrial respiration and myelin protein synthesis in rat brain glial cells. Enriched microglia showed an early burst in glycolysis. In microglia-conditioned medium, oligodendrocytes did not respire and expressed less myelin. SCENITH revealed metabolic derangement in microglia and O4-positive oligodendrocytes in endotoxemia and experimental autoimmune encephalitogenic models. The early burst of glycolysis in microglia was mediated by PDPK1 and protein kinase B/AKT signaling. We found that microglia-produced NO and itaconate, a tricarboxylic acid bifurcated metabolite, reduced mitochondrial respiration in oligodendrocytes. During inflammation, we discovered a signaling pathway in microglia that could be used as a therapeutic target to restore mitochondrial function in oligodendrocytes and induce remyelination.

Knockout of ACE-N facilitates improved cardiac function after myocardial infarction

Angiotensin-converting enzyme (ACE) hydrolyzes N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) into inactive fragments through its N-terminal site (ACE-N). We previously showed that Ac-SDKP mediates ACE inhibitors' cardiac effects. Whether increased bioavailability of endogenous Ac-SDKP caused by knocking out ACE-N also improves cardiac function in myocardial infarction (MI)-induced heart failure (HF) is unknown. Wild-type (WT) and ACE-N knockout (ACE-NKO) mice were subjected to MI by ligating the left anterior descending artery and treated with vehicle or Ac-SDKP (1.6 mg/kg/day, s.c.) for 5 weeks, after which echocardiography was performed and left ventricles (LV) were harvested for histology and molecular biology studies. ACE-NKO mice showed increased plasma Ac-SDKP concentrations in both sham and MI group compared to WT. Exogenous Ac-SDKP further increased its circulating concentrations in WT and ACE-NKO. Shortening (SF) and ejection (EF) fractions were significantly decreased in both WT and ACE-NKO mice post-MI, but ACE-NKO mice exhibited significantly lesser decrease. Exogenous Ac-SDKP ameliorated cardiac function post-MI only in WT but failed to show any additive improvement in ACE-NKO mice. Sarcoendoplasmic reticulum calcium transport ATPase (SERCA2), a marker of cardiac function and calcium homeostasis, was significantly decreased in WT post-MI but rescued with Ac-SDKP, whereas ACE-NKO mice displayed less loss of SERCA2 expression. Our study demonstrates that gene deletion of ACE-N resulted in improved LV cardiac function in mice post-MI, which is likely mediated by increased circulating Ac-SDKP and minimally reduced expression of SERCA2. Thus, future development of specific and selective inhibitors for ACE-N could represent a novel approach to increase endogenous Ac-SDKP toward protecting the heart from post-MI remodeling.

Blood-based untargeted metabolomics in relapsing-remitting multiple sclerosis revealed the testable therapeutic target

Metabolic aberrations impact the pathogenesis of multiple sclerosis (MS) and possibly can provide clues for new treatment strategies. Using untargeted metabolomics, we measured serum metabolites from 35 patients with relapsing-remitting multiple sclerosis (RRMS) and 14 healthy age-matched controls. Of 632 known metabolites detected, 60 were significantly altered in RRMS. Bioinformatics analysis identified an altered metabotype in patients with RRMS, represented by four changed metabolic pathways of glycerophospholipid, citrate cycle, sphingolipid, and pyruvate metabolism. Interestingly, the common upstream metabolic pathway feeding these four pathways is the glycolysis pathway. Real-time bioenergetic analysis of the patient-derived peripheral blood mononuclear cells showed enhanced glycolysis, supporting the altered metabolic state of immune cells. Experimental autoimmune encephalomyelitis mice treated with the glycolytic inhibitor 2-deoxy-D-glucose ameliorated the disease progression and inhibited the disease pathology significantly by promoting the antiinflammatory phenotype of monocytes/macrophage in the central nervous system. Our study provided a proof of principle for how a blood-based metabolomic approach using patient samples could lead to the identification of a therapeutic target for developing potential therapy.

AMP-Activated Protein Kinase Restricts Zika Virus Replication in Endothelial Cells by Potentiating Innate Antiviral Responses and Inhibiting Glycolysis

Viruses are known to perturb host cellular metabolism to enable their replication and spread. However, little is known about the interactions between Zika virus (ZIKV) infection and host metabolism. Using primary human retinal vascular endothelial cells and an established human endothelial cell line, we investigated the role of AMP-activated protein kinase (AMPK), a master regulator of energy metabolism, in response to ZIKV challenge. ZIKV infection caused a time-dependent reduction in the active phosphorylated state of AMPK and of its downstream target acetyl-CoA carboxylase. Pharmacological activation of AMPK using 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), metformin, and a specific AMPKα activator (GSK621) attenuated ZIKV replication. This activity was reversed by an AMPK inhibitor (compound C). Lentivirus-mediated knockdown of AMPK and the use of AMPKα^-/- mouse embryonic fibroblasts provided further evidence that AMPK has an antiviral effect on ZIKV replication. Consistent with its antiviral effect, AMPK activation potentiated the expression of genes with antiviral properties (e.g., IFNs, OAS2, ISG15, and MX1) and inhibited inflammatory mediators (e.g., TNF-α and CCL5). Bioenergetic analysis showed that ZIKV infection evokes a glycolytic response, as evidenced by elevated extracellular acidification rate and increased expression of key glycolytic genes (GLUT1, HK2, TPI, and MCT4); activation of AMPK by AICAR treatment reduced this response. Consistent with this, 2-deoxyglucose, an inhibitor of glycolysis, augmented AMPK activity and attenuated ZIKV replication. Thus, our study demonstrates that the anti-ZIKV effect of AMPK signaling in endothelial cells is mediated by reduction of viral-induced glycolysis and enhanced innate antiviral responses.

CBMT-48. TARGETING METABOLIC REPROGRAMMING WITH NANOCURCUMIN IN GLIOBLASTOMA MULTIFORME

Glioblastoma (GBM) is a highly glycolytic aggressive brain tumor characterized by increased proliferation and resistance to chemotherapy and radiotherapy. AMPK has been reported as tumor suppressor and reprograms the cellular metabolic pathways and produces a metabolic checkpoint on the cell cycle though mTORC1, p53 and other modulators involved in cell proliferation, growth, survival and autophagy. The AMPK activity is diminished in gastric, breast and ovarian tumor cells by activated PI3K-AKT pathways. Cancer cells are able to reprogram their energy metabolism to compensate their high bioenergetic demands needed for their aggressive growth and survival. Curcumin exhibits pleiotropic properties and activate MAPK and leads to suppress p53, Wnt/β-catenin, SHH and PI3K-AKT signaling pathways. Curcumin or diferuloylmethane is a yellow polyphenol extracted from the rhizome of turmeric (Curcuma longa). The absorption, biodistribution, metabolism, and elimination studies of curcumin have, unfortunately, shown only poor absorption, rapid metabolism, and elimination of curcumin as major reasons for poor bioavailability of this interesting polyphenolic compound. We have engineered a curcumin-based nanoparticle (Curc-NP) which demonstrates high water solubility. Curc-NP was effectively transported into the cells by nanoparticles through endocytosis and localized around the nuclei in the cytoplasms. In vitro studies proved that the cytotoxicity of Curc-NP is more effective against U-251 cell line in a dose-dependent manner. Systemic delivery of Curc-NP led to preferentially accumulation in an orthotopic preclinical glioma model minimizing systemic toxic effect. Multicolor microscopy images of the tumor tissue showed that Curc-NP particles were internalized inside tumor cells selectively and localized within nuclei. Curc-NP demonstrated to restore the dysregulated AMPK activity in glioma cells. Curc-NP-induced AMPK activation resulted in inhibition of oncogenic signalling pathways in glioma. Curc-NP-induced metabolic reprograming in glioma cells will be examined and the in vivo therapeutic efficacy of Curc-NP in an experimental rat model of GBM will also be evaluated.

Glycolytic regulation of neuroinflammatory response: Role of monocarboxylate transporter 4

Our study aimed to investigate the functional importance of the monocarboxylate transporter (MCT) 4 in vitro, in mouse primary mixed glial cells and in vivo, in mouse brain. Stimulation of primary mixed glial cells with LPS/IFNγ (LI)-induced the expression of MCT4. Inflammatory signals increase glycolysis and lactate production, which have been shown to sustain inflammatory response in immune cells. A real-time increase in glycolysis in LI-stimulated mixed glial cells was observed. We also found that IL-1β and NLRP3 expression was significantly increased in stimulated mixed glial cells, which are associated with chronic inflammatory diseases. MCT4 inhibitor, CHCA, significantly downregulated the proinflammatory response, glycolytic gene expression and real-time glycolysis in the primary mixed glial cells. As expected, CHCA blocked the release of lactate into the culture medium. Knockdown of MCT4 by using siRNA significantly attenuated the proinflammatory response suggesting that MCT4 could be a therapeutic target for neuroinflammatory diseases. Further, targeted metabolomics approach revealed that glycolytic intermediated, phosphoenolpyruvate and ribulose-1,5-bisphosphate, were significantly increased in primary mixed glial cells stimulated with LI, which were significantly decreased by CHCA treatment suggesting that intracellular accumulation of lactate attenuates glycolysis. CHCA treatment also diminished production of cytokines in the brain and spleen cells in an endotoxin mouse model. Importantly, we show that pharmacologic targeting of lactate transporters in glial cells might provide a novel and viable approach to resolve chronic inflammation in metabolic and neurodegenerative diseases.

Early burst of glycolysis in microglia regulates mitochondrial dysfunction in oligodendrocytes under neuro-inflammation

Brain resident microglia plays a pathological role in the loss of oligodendrocyte’s function under neuroinflammation. The precise signaling mechanism by which microglial driven factor attenuates the myelin gene expression under such condition is poorly defined. Here we used bioenergetic approach to understand the microglia-oligodendrocyte crosstalk. We found that mixed glial cells under inflammatory stimulation using lipopolysaccharide plus interferon gamma (LI) had significantly enhanced glycolysis with drastic attenuation of mitochondrial respiration and myelin gene expression. Dissecting the mixed glial culture into pure microglia, astrocyte and oligodendrocytes (OLs) revealed that primary microglia was the main source of higher glycolysis, inflammatory cytokines, and nitric oxide (NO). An early burst of glycolysis in microglia in response to LI treatment caused the production of inflammatory cytokines and NO, which is mediated by PDK1-Akt signaling. Culturing of OLs with LI-conditioned microglial media (mCM) resulted in complete failure of mitochondrial respiration in OLsalong with decreased expression of myelin genes. We identified that nitric oxide produced by microglia is the key player in the loss of mitochondrial respiration in OLs and targeting either glycolysis, PDK1 or Akt in microglia resulted in significant recovery of mitochondrial function and myelin genes expression in OLs. In summary, we identified a potential therapeutic signaling cascade in microglia; an early burst of glycolysis mediated by PDK1 and Akt, responsible for hyper-production of NO, ensuing in the failure of mitochondrial respiration in oligodendrocytes, and leading in reduction of myelin genes expression.

Blood-based untargeted metabolomics in Relapsing-Remitting Multiple Sclerosis revealed testable therapeutic target

Relapsing-remitting (RRMS), a most common form of MS, is characterized by acute attacks alternated by partial or complete recovery periods. The major focus of our research is to identify the therapeutic target using metabolomics. Metabolomics is a fast emerging field which can provide a direct “functional readout of the physiological state” of an organism. Identification of blood-based metabolic pathway(s) in relapsing-remitting form of MS (RRMS) which could be used for therapy. Using untargeted ultra-performance liquid and gas mass spectrometry, we measured serum metabolites from 33 RRMS patients, and 14 healthy subjects (HS). A total of 621 known metabolites were detected and 60 metabolites were significantly altered in the serum of RRMS compared to HS. Bioinformatics analysis revealed four metabolic pathways altered in RRMS including glycerophospholipid, citrate cycle, sphingolipids, and pyruvate metabolism. PBMCs isolated from RRMS patients exhibited higher glycolysis suggesting altered metabolic state of immune cells. EAE mice treated with glycolytic inhibitor 2-deoxyglucose (2-DG; once daily), resulted in a significantly delayed (P<0.001) the disease progression. 2DG inhibited (P<0.01) interleukin 17 production by reducing glycolysis (P<0.01) in monocytes of treated EAE group. Using untargeted metabolomic and Seahorse bioanalyzer approaches, we document that RRMS patients showed altered metabolic state “metabotype”. Targeting glycolysis, upstream of metabolic pathways altered in RRMS, using pharmacological inhibitor ameliorated the disease progression and pathology in a preclinical model of MS.

Analysis of stable isotope assisted metabolomics data acquired by GC-MS

Stable isotope assisted metabolomics (SIAM) measures the abundance levels of metabolites in a particular pathway using stable isotope tracers (e.g., ¹³C, ¹⁸O and/or ¹⁵N). We report a method termed signature ion approach for analysis of SIAM data acquired on a GC-MS system equipped with an electron ionization (EI) ion source. The signature ion is a fragment ion in EI mass spectrum of a derivatized metabolite that contains all atoms of the underivatized metabolite, except the hydrogen atoms lost during derivatization. In this approach, GC-MS data of metabolite standards were used to recognize the signature ion from the EI mass spectra acquired from stable isotope labeled samples, and a linear regression model was used to deconvolute the intensity of overlapping isotopologues. A mixture score function was also employed for cross-sample chromatographic peak list alignment to recognize the chromatographic peaks generated by the same metabolite in different samples, by simultaneously evaluating the similarity of retention time and EI mass spectrum of two chromatographic peaks. Analysis of a mixture of 16 ¹³C-labeled and 16 unlabeled amino acids showed that the signature ion approach accurately identified and quantified all isotopologues. Analysis of polar metabolite extracts from cells respectively fed with uniform ¹³C-glucose and ¹³C-glutamine further demonstrated that this method can also be used to analyze the complex data acquired from biological samples.

Untargeted Plasma Metabolomics Identifies Endogenous Metabolite with Drug-like Properties in Chronic Animal Model of Multiple Sclerosis

We performed untargeted metabolomics in plasma of B6 mice with experimental autoimmune encephalitis (EAE) at the chronic phase of the disease in search of an altered metabolic pathway(s). Of 324 metabolites measured, 100 metabolites that mapped to various pathways (mainly lipids) linked to mitochondrial function, inflammation, and membrane stability were observed to be significantly altered between EAE and control (p < 0.05, false discovery rate <0.10). Bioinformatics analysis revealed six metabolic pathways being impacted and altered in EAE, including α-linolenic acid and linoleic acid metabolism (PUFA). The metabolites of PUFAs, including ω-3 and ω-6 fatty acids, are commonly decreased in mouse models of multiple sclerosis (MS) and in patients with MS. Daily oral administration of resolvin D1, a downstream metabolite of ω-3, decreased disease progression by suppressing autoreactive T cells and inducing an M2 phenotype of monocytes/macrophages and resident brain microglial cells. This study provides a proof of principle for the application of metabolomics to identify an endogenous metabolite(s) possessing drug-like properties, which is assessed for therapy in preclinical mouse models of MS.

Targeted Stage-Specific Inflammatory microRNA Profiling in Urine During Disease Progression in Experimental Autoimmune Encephalomyelitis: Markers of Disease Progression and Drug Response

Recently, microRNAs (miRNAs) have been implicated in regulating neuroinflammatory and demyelinative responses in multiple sclerosis (MS) and its mouse model of experimental autoimmune encephalomyelitis (EAE). miRNAs have also been studied as biomarkers of disease pathology and drug-response in MS. However, no complete miRNA profiling at various stages of EAE disease has been examined, especially in the urine. We carried out a systematic analysis of miRNAs in the urine exosomes as well as in the plasma and spinal cord at pre-onset, onset and peak stages of EAE established in the chronic B6 mice model. For the first time, we provide evidence that urine exosomes can be a specific and sensitive source of miRNA biomarkers for all 3 stages of EAE disease. In a significant observation, we observed that miR-155-5p expression increased in urine exosomes, plasma and spinal cord 6 days before the onset of disease, suggesting its early involvement in the pathology of EAE disease. We also analyzed the effect of Glatiramer acetate (GA; copaxone) treatment, an approved treatment for MS patients, in modulating miRNA expression at the peak of EAE disease. We identified miR-155-5p, miR-27a-3p, miR-9-5p and miR-350-5p as putative GA-treatment responsive miRNA biomarkers. Since, EAE is a mainly CD4 cells mediated disease, we also examined the above set of miRNAs and found to be significantly altered in T cells polarized to Th1 and Th17 phenotype, similar to urine exosomes. Thus, urine exosome miRNAs hold the potential to be defined as novel accessible stage-specific biomarkers of EAE (MS) disease as well as treatment response.

Disease stage-specific profiling of miRNA in experimental autoimmune encephalomyelitis (IRM9P.732)

MicroRNAs (miRNAs) are small non-coding RNA molecules acting as post-transcriptional regulators of many physiological processes. Their dysregulation is implicated in various diseases, including multiple sclerosis (MS). Experimental autoimmune encephalomyelitis (EAE) is a well accepted mouse model of human MS disease. Many of the discoveries of human MS disease mechanism and drug development have come from studies conducted in EAE model. Depending on the mice background, EAE mice mimic two most common form of human MS; chronic (in C57B/6 mice) and relapsing-remitting (RR, in SJL mice). Dysregulated miRNA levels in biological fluids, such as plasma and urine, represent a new source of biomarkers in MS and EAE. In this study, we report the first systematic identification of disease stage-specific (pre-onset, onset, peak and resolution) miRNA expression in the plasma and urine exosomes of chronic mouse model of EAE. Each disease stage was represented by a specific subset of miRNA expression. We report for the first time identification of miR-155 in SC and urine exosomes of EAE mice much earlier (day 6 post immunization) than disease onset (day 12). Further, we evaluated the drug response of copaxone and metformin on miRNA expression. Identification of disease-stage-specific miRNA biomarkers in non-invasive fluids like urine could be helpful for disease prognosis and for discrimination of clinical subtype, thereby aiding therapeutic decisions and monitoring of therapeutic effects.

Profile of circulatory metabolites in chronic mouse model of multiple sclerosis using untargeted global metabolomics (THER3P.883)

Multiple sclerosis is a chronic inflammatory and demyelinating disease of the CNS. Although, MS is well characterized in terms of the role played by immune cells, cytokines and CNS pathology, nothing is known about the metabolic alterations that occur during the disease process in circulation. Here, we profiled the plasma metabolites of B6 with EAE, a known model of chronic MS using untargeted global metabolomics. Using a combination of high-throughput liquid-and-gas chromatography with mass spectrometry, a total of 326 metabolites were identified, with significant changes observed in 105 metabolites (13 up- and 92 down-regulated), that mapped to lipid and amino acid pathways, followed by the peptide, xenobiotic, carbohydrate, nucleotide and energy pathways (p&lt;0.05). To understand the functional role of these alterations, the KEGG metabolic library was analyzed using Metaboanalyst. The top nine most significant pathways in terms of GlobeTest p-value and impact are 1) fatty acid biosynthesis, 2) lysine degradation, 3) histidine metabolism, 4) beta-alanine metabolism, 5) pentose phosphate pathway, 6) arachidonic acid metabolism, 7) linoleic acid, 8) D-arginine and ornithine. Overall, these metabolic changes could be exploited as biomarkers for EAE/MS disease and to design new treatment paradigms where metabolic interventions could be combined with present and experimental therapeutics to achieve better treatment.

Loss of AMPKα1 in neuroinflammatory phenotype of X-linked adrenoleukodystrophy (HUM2P.335)

X-linked adrenoleukodystrophy (X-ALD) is the most common inherited neuroinflammatory demyelinating leukodystrophy. All X-ALD patients present with mutations in the ABCD1 gene, which encodes a peroxisomal adenosine triphosphate (ATP)-binding cassette transporter protein (ABCD1). X-ALD is a complex disease where the same mutation in the ALD gene (ABCD1) can lead to clinically very distinct phenotypes; a fatal neuroinflammatory childhood cerebral ALD (ALD) or the relatively benign disease of adrenomyeloneuropathy (AMN). Further, no relationship could be established between genotype and severity of the disease as same mutation is known to give different phenotypes, even within a family. We recently documented a role for decreased AMP kinaseα1 (AMPKα1) levels in initiating severe inflammatory and demyelinating phenotype in the CNS of AMPKα1-knockout mice. Abundant data is also available that implicates loss of AMPK in generating spontaneous inflammatory response in several cell types including immune cells. Our data using healthy control, AMN and ALD patient-derived skin fibroblasts and lymphocytes documents, for the first time, loss of a metabolic gene- AMPKα1 in ALD patient-derived fibroblasts and lymphocytes. Consistent with this, the basal expression of inflammatory cytokines (iNOS and IL-6) were increased in ALD patient-derived lymphocytes. Together these observations suggest that AMPKα1 may be involved in the progression of benign AMN to neuroinflammatory ALD phenotype.

Nontargeted urinary metabolite profiling of a chronic mouse model of multiple sclerosis (THER3P.884)

In search of metabolites signature as biomarkers during EAE disease, we profiled urine from B6 EAE using global untargeted metabolomics. Evaluation of metabolomic profiling of urine from EAE and healthy B6 group by using a combination of high-throughput liquid-and-gas chromatography with mass spectrometry, we found that 132 out of 322 (41%) metabolites were differentially altered (P&lt;0.05) indicating robust alteration in the urine metabolomics profile during disease. Among the perturbed metabolites, 11 were up regulated in EAE urine whereas 121 were down regulated. We conducted pathway analysis of the biochemical pathways of the KEGG and considered both concerted changes in metabolite intensity within the pathway (GlobalTest) and alterations of high impact, and found that a number of pathways were significantly altered including glyoxylate and dicarboxylate, phenylanine metabolism, porphyrin & chlorophyll metabolism, primary bile acid biosynthesis, cysteine & methione metabolism, taurine and hypotaurine metabolism, glycine, serine & threonine metabolism, and beta-alanine metabolism. Alteration in these pathways during EAE disease suggesting that perturbation of certain central metabolites could have impact on multiple metabolic pathways. While some of these metabolite changes could easily be developed as biomarkers, the key to translating metabolomics into therapeutics would require figuring out the central altered metabolic pathway(s), once studied in detail.

C9orf72 hexanucleotide repeat expansions as the causative mutation for chromosome 9p21-linked amyotrophic lateral sclerosis and frontotemporal dementia

OBJECTIVE

To further assess the presence of a large hexanucleotide repeat expansion in the first intron of the C9orf72 gene identified as the genetic cause of chromosome 9p21-linked amyotrophic lateral sclerosis and frontotemporal dementia (c9ALS/FTD) in 4 unrelated families with a conclusive linkage to c9ALS/FTD.

DESIGN

A repeat-primed polymerase chain reaction assay.

SETTING

Academic research.

PARTICIPANTS

Affected and unaffected individuals from 4 ALS/FTD families.

MAIN OUTCOME MEASURE

The amplified C9orf72 repeat expansion.

RESULTS

We show that the repeat is expanded in and segregated perfectly with the disease in these 4 pedigrees.

CONCLUSION

Our findings further confirm the C9orf72 hexanucleotide repeat expansion as the causative mutation for c9ALS/FTD and strengthen the hypothesis that ALS and FTD belong to the same disease spectrum.

Serological and clinical features of patients with myasthenia gravis in north Indian population

Myasthenia gravis (MG) is a disorder of neuromuscular junction associated with presence of antibodies against nicotinic acetylcholine receptors (nAChRs). Here, we compared the clinical and serological profile of seropositive myasthenia gravis (SPMG) and seronegative myasthenia gravis (SNMG) patients. Anti-AChR antibody was measured using radio receptor immunoassay and correlated with clinical phenotype in 250 MG patients over 2004 and 2006. Out of 250 MG patients, 161 (64.4%) were males (male:female = 1.8:1). SNMG patients formed 40% (n = 101) of our MG patients which is much higher as compared to Caucasian and Oriental population (15%-20%). The median age of disease onset in SPMG was significantly higher than SNMG patients (43 years; range 8-74 vs. 35 years; range 4-72, p = .022). A bimodal peak of age of disease onset in both genders was observed (first peak in second-third decades and second one in fifth-sixth decades). Among the MG patients with late-onset of disease, male were significantly higher compared to Caucasian and Oriental MG population (p = .047). MG patients with thymoma were significantly older and consisted of higher percent of males. Bulbar symptoms and severe grade (IIB+ III+ IV) at disease onset were more frequent in SPMG than SNMG patients.