ELP1 Splicing Correction Reverses Proprioceptive Sensory Loss in Familial Dysautonomia.

Familial dysautonomia (FD) is a recessive neurodegenerative disease caused by a splice mutation in Elongator complex protein 1 (ELP1, also known as IKBKAP); this mutation leads to variable skipping of exon 20 and to a drastic reduction of ELP1 in the nervous system. Clinically, many of the debilitating aspects of the disease are related to a progressive loss of proprioception; this loss leads to severe gait ataxia, spinal deformities, and respiratory insufficiency due to neuromuscular incoordination. There is currently no effective treatment for FD, and the disease is ultimately fatal. The development of a drug that targets the underlying molecular defect provides hope that the drastic peripheral neurodegeneration characteristic of FD can be halted. We demonstrate herein that the FD mouse TgFD9;IkbkapΔ20/flox recapitulates the proprioceptive impairment observed in individuals with FD, and we provide the in vivo evidence that postnatal correction, promoted by the small molecule kinetin, of the mutant ELP1 splicing can rescue neurological phenotypes in FD. Daily administration of kinetin starting at birth improves sensory-motor coordination and prevents the onset of spinal abnormalities by stopping the loss of proprioceptive neurons. These phenotypic improvements correlate with increased amounts of full-length ELP1 mRNA and protein in multiple tissues, including in the peripheral nervous system (PNS). Our results show that postnatal correction of the underlying ELP1 splicing defect can rescue devastating disease phenotypes and is therefore a viable therapeutic approach for persons with FD.

Uncommon side effects of common drugs in patients with familial dysautonomia.

PURPOSE: Patients with the autosomal recessive disorder of familial dysautonomia typically exhibit exacerbated adverse side effects to many common drugs. We aimed to catalog these adverse effects - with a focus on common drugs that are frequently administered to FD patients and compare their incidences to those within the general population. METHODS: We used data of 595 FD patients from an international database with information on drugs received and adverse effects. To investigate the molecular causes of reported differences in drug responses in FD patients, we used expression microarrays to compare the mRNA expression profiles in peripheral blood leukocytes of FD patients (n = 12) and healthy individuals (n = 10). RESULTS: Several drug classes, including cholinergics, anti-cholinergics, anti-convulsants, methylxanthines, SSRIs, and antibiotics caused either unreported symptoms or elevated rates of adverse events in FD patients. FD patients experienced different or more frequent adverse side effects than the general population in 31/123 drugs. These side effects included blood cell dyscrasias, amenorrhea, gastrointestinal bleeding, and bronchospasm. New findings include enhanced reaction of FD patients to H2 antagonist agents and to serotonin receptor agonists. We also detected eight genes differentially expressed between FD patients and healthy individuals that may underlie the differential drug responses of FD patients. CONCLUSION: We provide evidence that suggests the use of several common drugs should be discontinued or reduced in FD patients.

Application of nursing intervention based on the IKAP model in self-management of patients with gastric cancer.

BACKGROUND: To explore the effect of IKAP nursing intervention on the self-management of patients with gastric cancer, so as to improve the patient's disease management ability and healthy behaviors. METHODS: In this retrospective study, a total of 124 patients with gastric cancer were included. The experimental group received the self-management intervention program for gastric cancer patients based on the IKAP model, and the control group only received routine nursing. The psychological status, quality of life, cancer-related symptoms, and self-management ability of the two groups were observed; moreover, multiple regression analysis was used to identify the risk factors of self-management. RESULTS: The nursing intervention based on the IKAP model had obvious effects on patients with gastric cancer. The SUPPH score was improved significantly after nursing intervention in the experimental group, and the improvement was more significant as compared to control group (both P < 0.05). The quality of life was significantly improved in the experimental group as compared with control group. The incidence of partial cancer-related symptoms, such as infection, fatigue and recurrent peptic ulcer in the experimental group was significantly lower after nursing intervention as compared with control group (all P < 0.05). Moreover, the regression analysis showed that being single, divorced or separated, widowed, as well as self-management nursing intervention, and quality of life showed significant correlation with self-management behavior. The multiple regression analysis demonstrated that psychological function (p = 0.003) and self-management nursing intervention (p < 0.0001) were the independent risk factors. CONCLUSIONS: Nursing intervention based on the IKAP model for patients with gastric cancer plays a positive role in improving the self-management ability of gastric cancer patients and improving their negative emotions.

Retina-specific loss of Ikbkap/Elp1 causes mitochondrial dysfunction that leads to selective retinal ganglion cell degeneration in a mouse model of familial dysautonomia.

Familial dysautonomia (FD) is an autosomal recessive disorder marked by developmental and progressive neuropathies. It is caused by an intronic point-mutation in the IKBKAP/ELP1 gene, which encodes the inhibitor of κB kinase complex-associated protein (IKAP, also called ELP1), a component of the elongator complex. Owing to variation in tissue-specific splicing, the mutation primarily affects the nervous system. One of the most debilitating hallmarks of FD that affects patients' quality of life is progressive blindness. To determine the pathophysiological mechanisms that are triggered by the absence of IKAP in the retina, we generated retina-specific Ikbkap conditional knockout (CKO) mice using Pax6-Cre, which abolished Ikbkap expression in all cell types of the retina. Although sensory and autonomic neuropathies in FD are known to be developmental in origin, the loss of IKAP in the retina did not affect its development, demonstrating that IKAP is not required for retinal development. The loss of IKAP caused progressive degeneration of retinal ganglion cells (RGCs) by 1 month of age. Mitochondrial membrane integrity was breached in RGCs, and later in other retinal neurons. In Ikbkap CKO retinas, mitochondria were depolarized, and complex I function and ATP were significantly reduced. Although mitochondrial impairment was detected in all Ikbkap-deficient retinal neurons, RGCs were the only cell type to degenerate; the survival of other retinal neurons was unaffected. This retina-specific FD model is a useful in vivo model for testing potential therapeutics for mitigating blindness in FD. Moreover, our data indicate that RGCs and mitochondria are promising targets.

Structures and Activities of the Elongator Complex and Its Cofactors.

Elongator is a highly conserved eukaryotic protein complex consisting of two sets of six Elp proteins, while homologues of its catalytic subunit Elp3 are found in all the kingdoms of life. Although it was originally described as a transcription elongation factor, cumulating evidence suggests that its primary function is catalyzing tRNA modifications. In humans, defects in Elongator subunits are associated with neurological disorders and cancer. Although further studies are still required, a clearer picture of the molecular mechanism of action of Elongator and its cofactors has started to emerge within recent years that have witnessed significant development in the field. In this review we summarize recent Elongator-related findings provided largely by crystal structures of several subunits of the complex, the electron microscopy structure of the entire yeast holoenzyme, as well as the structure of the Elongator cofactor complex Kti11/Kti13.

Tocotrienol Treatment in Familial Dysautonomia: Open-Label Pilot Study.

Familial dysautonomia (FD) is an autosomal recessive congenital neuropathy, primarily presented in Ashkenazi Jews. The most common mutation in FD patients results from a single base pair substitution of an intronic splice site in the IKBKAP gene which disrupts normal mRNA splicing and leads to tissue-specific reduction of IKBKAP protein (IKAP). To date, treatment of FD patients remains preventative, symptomatic and supportive. Based on previous in vitro evidence that tocotrienols, members of the vitamin E family, upregulate transcription of the IKBKAP gene, we aimed to investigate whether a similar effects was observed in vivo. In the current study, we assessed the effects of tocotrienol treatment on FD patients' symptoms and IKBKAP expression in white blood cells. The initial daily doses of 50 or 100 mg tocotrienol, doubled after 3 months, was administered to 32 FD patients. Twenty-eight FD patients completed the 6-month study. The first 3 months of tocotrienol treatment was associated with a significant increase in IKBKAP expression level in FD patients' blood. Despite doubling the dose after the initial 3 months of treatment, IKBKAP expression level returned to baseline by the end of the 6-month treatment. Clinical improvement was noted in the reported clinical questionnaire (with regard to dizziness, bloching, sweating, number of pneumonia, cough episodes, and walking stability), however, no significant effect was observed in any clinical measurements (weight, height, oxygen saturation, blood pressure, tear production, histamine test, vibration threshold test, nerve conduction, and heart rate variability) following Tocotrienol treatment. In conclusion, tocotrienol treatment appears significantly beneficial by clinical evaluation for some FD patients in a few clinical parameters; however it was not significant by clinical measurements. This open-label study shows the complexity of effect of tocotrienol treatment on FD patients' clinical outcomes and on IKBKAP expression level compared to in vitro results. A longitudinal study with an increased sample size is required in the future to better understand tocotrienol affect on FD patients.

Loss of Ikbkap Causes Slow, Progressive Retinal Degeneration in a Mouse Model of Familial Dysautonomia.

Familial dysautonomia (FD) is an autosomal recessive congenital neuropathy that is caused by a mutation in the gene for inhibitor of kappa B kinase complex-associated protein (IKBKAP). Although FD patients suffer from multiple neuropathies, a major debilitation that affects their quality of life is progressive blindness. To determine the requirement for Ikbkap in the developing and adult retina, we generated Ikbkap conditional knockout (CKO) mice using a TUBA1a promoter-Cre (Tα1-Cre). In the retina, Tα1-Cre expression is detected predominantly in retinal ganglion cells (RGCs). At 6 months, significant loss of RGCs had occurred in the CKO retinas, with the greatest loss in the temporal retina, which is the same spatial phenotype observed in FD, Leber hereditary optic neuropathy, and dominant optic atrophy. Interestingly, the melanopsin-positive RGCs were resistant to degeneration. By 9 months, signs of photoreceptor degeneration were observed, which later progressed to panretinal degeneration, including RGC and photoreceptor loss, optic nerve thinning, Müller glial activation, and disruption of layers. Taking these results together, we conclude that although Ikbkap is not required for normal development of RGCs, its loss causes a slow, progressive RGC degeneration most severely in the temporal retina, which is later followed by indirect photoreceptor loss and complete retinal disorganization. This mouse model of FD is not only useful for identifying the mechanisms mediating retinal degeneration, but also provides a model system in which to attempt to test therapeutics that may mitigate the loss of vision in FD patients.

MicroRNA screening identifies a link between NOVA1 expression and a low level of IKAP in familial dysautonomia.

Familial dysautonomia (FD) is a rare neurodegenerative disease caused by a mutation in intron 20 of the IKBKAP gene (c.2204+6T>C), leading to tissue-specific skipping of exon 20 and a decrease in the synthesis of the encoded protein IKAP (also known as ELP1). Small non-coding RNAs known as microRNAs (miRNAs) are important post-transcriptional regulators of gene expression and play an essential role in the nervous system development and function. To better understand the neuronal specificity of IKAP loss, we examined expression of miRNAs in human olfactory ecto-mesenchymal stem cells (hOE-MSCs) from five control individuals and five FD patients. We profiled the expression of 373 miRNAs using microfluidics and reverse transcription coupled to quantitative PCR (RT-qPCR) on two biological replicate series of hOE-MSC cultures from healthy controls and FD patients. This led to the total identification of 26 dysregulated miRNAs in FD, validating the existence of a miRNA signature in FD. We then selected the nine most discriminant miRNAs for further analysis. The signaling pathways affected by these dysregulated miRNAs were largely within the nervous system. In addition, many targets of these dysregulated miRNAs had been previously demonstrated to be affected in FD models. Moreover, we found that four of our nine candidate miRNAs target the neuron-specific splicing factor NOVA1. We demonstrated that overexpression of miR-203a-3p leads to a decrease of NOVA1, counter-balanced by an increase of IKAP, supporting a potential interaction between NOVA1 and IKAP. Taken together, these results reinforce the choice of miRNAs as potential therapeutic targets and suggest that NOVA1 could be a regulator of FD pathophysiology.

Dynamic changes in IKBKAP mRNA levels during crisis of familial dysautonomia patients.

UNLABELLED: Familial dysautonomia is a neurodegenerative, genetic disorder caused by an autosomal recessive mutation in the IKBKAP gene, which encodes the IkB kinase complex-associated protein. Familial dysautonomia patients have recurrent crises characterized by bouts of nausea, vomiting, hypertension, tachycardia, sweating, blotching and personality changes. The dysautonomia crisis is usually triggered by stressful physiological or emotional events, however the pathophysiology of the crisis is not yet fully clear and little is known about the molecular mechanisms involved in onset and consequences of the crisis. OBJECTIVE: We have investigated the dysautonomia crisis by evaluating the expression of the familial dysautonomia gene - IKBKAP, in patients during different crisis stages. METHOD: Baseline IKBKAP mRNA levels in white blood cells were evaluated in thirteen FD patients (fourteen crisis events) and compared to mRNA levels at the onset, during, and after recovery from the crisis. RESULTS: We have found a significant decrease in IKBKAP mRNA level during the crisis, which is restored to a baseline level after recovery from the crisis. CONCLUSION: We speculate that the familial dysautonomia crisis pathophysiology might be related, at least in part, to the down regulation of the IKBKAP gene. Yet, it is still unclear whether the down regulation in IKBKAP mRNA is caused by the physiological stress events which have triggered the crisis or whether this molecular change is a consequence of the crisis.