Nagaraj S. Moily

Shortened telomere in unremitted schizophrenia

Telomere attrition has been noted in many neuropsychiatric and neurodegenerative syndromes, and may indicate a shared molecular pathology across conditions. We evaluated telomere length in subjects with remitted and unremitted schizophrenia and in control subjects.

Huntingtin Inclusions Trigger Cellular Quiescence, Deactivate Apoptosis, and Lead to Delayed Necrosis

Competing models exist in the literature for the relationship between mutant Huntingtin exon 1 (Httex1) inclusion formation and toxicity. In one, inclusions are adaptive by sequestering the proteotoxicity of soluble Httex1. In the other, inclusions compromise cellular activity as a result of proteome co-aggregation. Using a biosensor of Httex1 conformation in mammalian cell models, we discovered a mechanism that reconciles these competing models. Newly formed inclusions were composed of disordered Httex1 and ribonucleoproteins. As inclusions matured, Httex1 reconfigured into amyloid, and other glutamine-rich and prion domain-containing proteins were recruited. Soluble Httex1 caused a hyperpolarized mitochondrial membrane potential, increased reactive oxygen species, and promoted apoptosis. Inclusion formation triggered a collapsed mitochondrial potential, cellular quiescence, and deactivated apoptosis. We propose a revised model where sequestration of soluble Httex1 inclusions can remove the trigger for apoptosis but also co-aggregate other proteins, which curtails cellular metabolism and leads to a slow death by necrosis.

Off label use of lithium in the treatment of Huntington's disease: A case series

Huntingtons disease is characterized by choreic movements, psychiatric disorders, striatal atrophy with selective small neuronal loss, and autosomal dominant inheritance. The genetic abnormality is CAG expansion in Huntingtin gene. Newer therapeutic strategies are evolving to treat this progressive disorder. The neuroprotective agents are one such group of drugs being tried. Lithium has been used to treat Huntingtons disease in the past due to its neuroprotective effects. Though the precise mechanism of action is not clear, Lithium can directly or indirectly modulate proteins involved in neuronal survival/differentiation which may account for its neuroprotective effects. We report three patients with Huntingtons disease in whom Lithium prevented the progression of chorea and also helped stabilize mood.

A thiol probe for measuring unfolded protein load and proteostasis in cells

When proteostasis becomes unbalanced, unfolded proteins can accumulate and aggregate. Here we report that the dye, tetraphenylethene maleimide (TPE-MI) can be used to measure cellular unfolded protein load. TPE-MI fluorescence is activated upon labelling free cysteine thiols, normally buried in the core of globular proteins that are exposed upon unfolding. Crucially TPE-MI does not become fluorescent when conjugated to soluble glutathione. We find that TPE-MI fluorescence is enhanced upon reaction with cellular proteomes under conditions promoting accumulation of unfolded proteins. TPE-MI reactivity can be used to track which proteins expose more cysteine residues under stress through proteomic analysis. We show that TPE-MI can report imbalances in proteostasis in induced pluripotent stem cell models of Huntington disease, as well as cells transfected with mutant Huntington exon 1 before the formation of visible aggregates. TPE-MI also detects protein damage following dihydroartemisinin treatment of the malaria parasites Plasmodium falciparum. TPE-MI therefore holds promise as a tool to probe proteostasis mechanisms in disease.Proteostasis is maintained through a number of molecular mechanisms, some of which function to protect the folded state of proteins. Here the authors demonstrate the use of TPE-MI in a fluorigenic dye assay for the quantitation of unfolded proteins that can be used to assess proteostasis on a cellular or proteome scale.

Reduced Telomere Length in Neurodegenerative Disorders May Suggest Shared Biology

Early cell death is a feature of neurodegenerative disorders. Telomere shortening is related to premature cellular senescence and could be a marker for cellular pathology in neurological diseases. Relative telomere length in dementia (N=70), Huntingtons disease (N=35), ataxia telangiectasia (N=9), and age-group matched control samples (N=105) was measured as relative telomere copy/single copy gene ratios. Individuals with Huntingtons disease had the lowest relative telomere copy/single copy gene ratio (0.21), followed by ataxia telangiectasia (0.31) and dementia (0.48). The younger control group had the highest relative telomere copy/single copy gene ratio (1.07). The reduced telomere length could be indicative of shared biological pathways across these disorders contributing to cellular senescence.

Genetic studies indicate a potential target 5-HTR3B for Drug Therapy in Schizophrenia Patients†‡

Genetic Studies Indicate a Potential Target 5-HTR3B for Drug Therapy in Schizophrenia Patients Meenal Gupta, Sanjeev Jain, Nagaraj Moily, Harpreet Kaur, Ajay Jajodia, Meera Purushottam, and Ritushree Kukreti* Genomics and Molecular Medicine, Institute of Genomics and Integrative Biology (Council of Scientific and Industrial Research), Delhi, India Molecular Genetic Laboratory, Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bangalore, India

Transcriptional profiles for distinct aggregation states of mutant Huntingtin exon 1 protein unmask new Huntington's disease pathways

&NA; Huntingtons disease is caused by polyglutamine (polyQ)‐expansion mutations in the CAG tandem repeat of the Huntingtin gene. The central feature of Huntingtons disease pathology is the aggregation of mutant Huntingtin (Htt) protein into micrometer‐sized inclusion bodies. Soluble mutant Htt states are most proteotoxic and trigger an enhanced risk of death whereas inclusions confer different changes to cellular health, and may even provide adaptive responses to stress. Yet the molecular mechanisms underpinning these changes remain unclear. Using the flow cytometry method of pulse‐shape analysis (PulSA) to sort neuroblastoma (Neuro2a) cells enriched with mutant or wild‐type Htt into different aggregation states, we clarified which transcriptional signatures were specifically attributable to cells before versus after inclusion assembly. Dampened CREB signalling was the most striking change overall and invoked specifically by soluble mutant Httex1 states. Toxicity could be rescued by stimulation of CREB signalling. Other biological processes mapped to different changes before and after aggregation included NF‐kB signalling, autophagy, SUMOylation, transcription regulation by histone deacetylases and BRD4, NAD + biosynthesis, ribosome biogenesis and altered HIF‐1 signalling. These findings open the path for therapeutic strategies targeting key molecular changes invoked prior to, and subsequently to, Httex1 aggregation. HighlightsTranscriptional changes due to aggregation of mutant Httex1 are described.The largest changes in the transcriptome are stimulated by soluble mutant Httex1.Inactivated CREB signalling is the most profound impact arising from soluble Httex1.Dampened CREB signalling explains the molecular basis of toxicity.Additional pathways unearthed as transcriptional signatures for Httex1 aggregation.

Determinants of Onset of Huntington's Disease with Behavioral Symptoms: Insight from 92 Patients.

BACKGROUND Huntingtons disease (HD) is a genetically mediated neurodegenerative disorder characterized by presence of involuntary movements, behavioral problems and cognitive dysfunctions. Though few patients with HD may have behavioral symptoms at onset of the disease, studies comparing patients with behavioral symptoms at the onset of HD with those having motor symptoms are sparse. OBJECTIVE Objective of this study is to determine the differences in the demographic and genetic characteristics of patients with behavioral symptom at the onset of HD from those with motor symptoms. METHODS A chart review of 92 patients with HD who had attended the neurology outpatient clinics of National Institute of Mental Health and Neurosciences, India was done. Demographic and genetic characteristics of HD patients with onset of the disease with initial behavioral symptoms (HD-iB) were compared with patients with onset of the disease with initial motor symptoms (HD-iM). RESULTS The principal findings in our study were (i) higher proportion of patients with HD-iB had a positive family history of HD, (ii) maternal inheritance of HD was more frequent among those with HD-iB, and (iii) There is no significant difference between the CAG repeat length between HD-iB and HD-iM groups. CONCLUSION Presence of family history of HD especially inheritance of HD from mother may be associated with behavioral symptoms at the onset of HD. CAG repeat length in patients with HD-iB does not differ from those with HD-iM.

Genetic testing for clinically suspected spinocerebellar ataxias: report from a tertiary referral centre in India

Spinocerebellar ataxias (SCAs) are a heterogeneous group of neurodegenerative syndromes, characterized by a wide range of muscular weakness and motor deficits, caused due to cerebellar degeneration. The prevalence of the syndromes of SCA varies across the world and is known to be linked to the instability of trinucleotide repeats within the high-end normal alleles, along with susceptible haplotype. We estimated sizes of the CAG or GAA repeat expansions at the SCA1, SCA2, SCA3, SCA12 and frataxin loci among 864 referrals of subjects to genetic counselling and testing (GCAT) clinic, National Institute of Mental Health and Neurosciences, Bengaluru, India, with suspected SCA. The most frequent mutations detected were SCA1 (