Splice modulators target PMS1 to reduce somatic expansion of the Huntington's disease-associated CAG repeat.

Huntington's disease (HD) is a dominant neurological disorder caused by an expanded HTT exon 1 CAG repeat that lengthens huntingtin's polyglutamine tract. Lowering mutant huntingtin has been proposed for treating HD, but genetic modifiers implicate somatic CAG repeat expansion as the driver of onset. We find that branaplam and risdiplam, small molecule splice modulators that lower huntingtin by promoting HTT pseudoexon inclusion, also decrease expansion of an unstable HTT exon 1 CAG repeat in an engineered cell model. Targeted CRISPR-Cas9 editing shows this effect is not due to huntingtin lowering, pointing instead to pseudoexon inclusion in PMS1. Homozygous but not heterozygous inactivation of PMS1 also reduces CAG repeat expansion, supporting PMS1 as a genetic modifier of HD and a potential target for therapeutic intervention. Although splice modulation provides one strategy, genome-wide transcriptomics also emphasize consideration of cell-type specific effects and polymorphic variation at both target and off-target sites.

Rescue of a familial dysautonomia mouse model by AAV9-Exon-specific U1 snRNA.

Familial dysautonomia (FD) is a currently untreatable, neurodegenerative disease caused by a splicing mutation (c.2204+6T>C) that causes skipping of exon 20 of the elongator complex protein 1 (ELP1) pre-mRNA. Here, we used adeno-associated virus serotype 9 (AAV9-U1-FD) to deliver an exon-specific U1 (ExSpeU1) small nuclear RNA, designed to cause inclusion of ELP1 exon 20 only in those cells expressing the target pre-mRNA, in a phenotypic mouse model of FD. Postnatal systemic and intracerebral ventricular treatment in these mice increased the inclusion of ELP1 exon 20. This also augmented the production of functional protein in several tissues including brain, dorsal root, and trigeminal ganglia. Crucially, the treatment rescued most of the FD mouse mortality before one month of age (89% vs 52%). There were notable improvements in ataxic gait as well as renal (serum creatinine) and cardiac (ejection fraction) functions. RNA-seq analyses of dorsal root ganglia from treated mice and human cells overexpressing FD-ExSpeU1 revealed only minimal global changes in gene expression and splicing. Overall then, our data prove that AAV9-U1-FD is highly specific and will likely be a safe and effective therapeutic strategy for this debilitating disease.

Neurological Presentation of Giant Pituitary Tumour Apoplexy: Case Report and Literature Review of a Rare but Life-Threatening Condition.

Background: Giant pituitary adenomas are benign intracranial tumours with a diameter ≥4 cm. Even if hormonally non-functional, they may still cause local extension, leading to symptoms that include mostly gland dysfunction, mass effects, and, much less frequently, apoplexy due to haemorrhage or infarction. Neurological presentation of giant pituitary tumour apoplexy is even more rare and has not been systematically reviewed. Case Presentation: An 81-year-old woman was admitted to the Emergency Department because of acute onset headache, bilateral visual deficit, and altered consciousness. Computed tomography showed a giant mass lesion (>5.5 cm diameter) expanding upward to the suprasellar cistern, optic chiasm, and third ventricle, over-running the sphenoid sinus, and with lateral invasion of the cavernous sinus. Laboratory investigations revealed central adrenal and hypothyroidism insufficiency, while magnetic resonance imaging confirmed a voluminous suprasellar tumour (~6 cm diameter), with signs of pituitary tumour apoplexy. Neurological manifestations and gland-related deficits improved after hormonal replacement therapy with a high dose of intravenous hydrocortisone, followed by oral hydrocortisone and levo-thyroxine. The patient declined surgical treatment and follow-up visit. Conclusions: Giant pituitary tumour apoplexy is a rare but potentially life-threatening condition. Prompt diagnosis and multidisciplinary management may allow a remarkable clinical improvement, as seen in this case.

A deep learning approach to identify gene targets of a therapeutic for human splicing disorders.

Pre-mRNA splicing is a key controller of human gene expression. Disturbances in splicing due to mutation lead to dysregulated protein expression and contribute to a substantial fraction of human disease. Several classes of splicing modulator compounds (SMCs) have been recently identified and establish that pre-mRNA splicing represents a target for therapy. We describe herein the identification of BPN-15477, a SMC that restores correct splicing of ELP1 exon 20. Using transcriptome sequencing from treated fibroblast cells and a machine learning approach, we identify BPN-15477 responsive sequence signatures. We then leverage this model to discover 155 human disease genes harboring ClinVar mutations predicted to alter pre-mRNA splicing as targets for BPN-15477. Splicing assays confirm successful correction of splicing defects caused by mutations in CFTR, LIPA, MLH1 and MAPT. Subsequent validations in two disease-relevant cellular models demonstrate that BPN-15477 increases functional protein, confirming the clinical potential of our predictions.

Breathlessness in amyotrophic lateral sclerosis: A case report on the role of osteoporosis in the worsening of respiratory failure.

RATIONALE: Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative multisystem disorder, presenting with limb or bulbar onset. To date, there is no cure for ALS. At some stage of the disease, patients may complain of breathlessness due to respiratory failure, thus needing a noninvasive mechanical ventilation (NIMV) support. However, breathlessness is a symptom that may be induced by different causes that must be taken into consideration in ALS management. PATIENTS CONCERNS: We report the case of an 81-year-old man, with a spinal onset ALS, who was admitted to our clinic to start NIMV because of respiratory involvement. After 3 weeks from NIMV performed at night time, with beneficial effects, he suddenly complained of breathlessness even at rest and in standing position. DIAGNOSIS: Respiratory and cardiac assessments did not show new clinical events, indicating the worsening respiratory function. Due to a history of osteoporosis which was treated with biphosphonates and even though no previous bone trauma or falls were reported, we performed a spine computed tomography scan. The findings indicated multiple dorsal vertebral fractures which was a probable cause for breathlessness. INTERVENTIONS AND OUTCOMES: Considering the neurodegenerative disease associated to respiratory failure, the cardiovascular risk factors and the age, the patient refused to undergo a surgery with kyphoplasty. A spine support was then prescribed, together with analgesic medications, with significant alleviation of pain and breathlessness. LESSONS: The occurrence of breathlessness in a patient with ALS cannot always be related to the bulbar involvement. Other causes should be taken into account, especially when there is sudden worsening of symptoms in spite of good clinical response and compliance to NIMV treatment.

Exon-specific U1 snRNAs improve ELP1 exon 20 definition and rescue ELP1 protein expression in a familial dysautonomia mouse model.

Familial dysautonomia (FD) is a rare genetic disease with no treatment, caused by an intronic point mutation (c.2204+6T>C) that negatively affects the definition of exon 20 in the elongator complex protein 1 gene (ELP1 also known as IKBKAP). This substitution modifies the 5' splice site and, in combination with regulatory splicing factors, induces different levels of exon 20 skipping, in various tissues. Here, we evaluated the therapeutic potential of a novel class of U1 snRNA molecules, exon-specific U1s (ExSpeU1s), in correcting ELP1 exon 20 recognition. Lentivirus-mediated expression of ELP1-ExSpeU1 in FD fibroblasts improved ELP1 splicing and protein levels. We next focused on a transgenic mouse model that recapitulates the same tissue-specific mis-splicing seen in FD patients. Intraperitoneal delivery of ELP1-ExSpeU1s-adeno-associated virus particles successfully increased the production of full-length human ELP1 transcript and protein. This splice-switching class of molecules is the first to specifically correct the ELP1 exon 20 splicing defect. Our data provide proof of principle of ExSpeU1s-adeno-associated virus particles as a novel therapeutic strategy for FD.

Bone health assessment by quantitative ultrasound and dual-energy x-ray absorptiometry in postmenopausal women with breast cancer receiving aromatase inhibitors.

OBJECTIVE: Phalangeal quantitative ultrasound (QUS) measurements provide surrogate information on bone quality. The aim of the present study was to assess bone status by phalangeal QUS and by dual-energy x-ray absorptiometry (DXA), and to evaluate bone turnover in breast cancer (BC) women receiving aromatase inhibitors (AIs). METHODS: Sixty postmenopausal BC women and 42 matched controls were recruited (mean age 61.64 ±â€Š8.33 y). Amplitude-dependent speed of sound (AD-SoS), bone transmission time (BTT), Ultrasound Bone Profile Index, as QUS parameters, L1-L4 and femoral neck BMD by DXA were assessed at baseline and after 18 months; serum bone-specific alkaline phosphatase (BSAP) and C-telopeptide of type 1 collagen were measured at baseline, 9 and 18 months. RESULTS: FRAX (without BMD) derived 10-years probability of major fractures and hip fractures were significantly associated with AD-SoS (r = -0.381, P = < 0.001 and r = -0.370, P < 0.001, respectively), Ultrasound Bone Profile Index (r = -0.434, P ≤ 0.001 and r = -0.409, P = < 0.001, respectively), BTT (r = -0.309, P = 0.002 and r = -0.340, P = 0.001, respectively). The median percent changes of AD-SoS (-3.71 [-5.38 to 0.11] vs -0.7 [-4.15 to 0.83], P = 0.02 respectively), BTT (-8.4 [-14.91 to -3.53] vs -1 [-5.72 to 3.75], P < 0.001 respectively) were significantly different between AIs users and controls. The same trend was observed for DXA measurements. BSAP and C-telopeptide of type 1 collagen significantly changed in AIs users. AD-SoS was associated with change of BMD at lumbar spine (ß, 0.16; SE, 0.08; P = 0.04) and change of BSAP (ß, -0.04; SE, 0.02; P = 0.04). CONCLUSIONS: Phalangeal QUS appeared a useful tool to evaluate bone quality in BC women on AIs.

Denosumab Inhibition of RANKL and Insulin Resistance in Postmenopausal Women with Osteoporosis.

The tumor necrosis factor-related cytokine receptor activator of nuclear factor kappa B ligand (RANKL) has been proposed as predictor of incident type 2 diabetes mellitus, and experimental blockade of RANKL resulted in a marked improvement of glucose tolerance. Denosumab is a fully human monoclonal antibody that binds to RANKL and prevents osteoclast formation, function and survival, leading to fracture risk reduction. The aim of our study was to investigate glucometabolic parameters, insulin resistance, and lipid profile in non-diabetic women receiving denosumab. Forty-eight women with postmenopausal osteoporosis were enrolled and treated with a subcutaneous dose (60 mg) of denosumab. At baseline and after 4, 12, ad 24 weeks, insulin resistance was computed by homeostasis model assessment of insulin resistance (HOMA-IR) and total cholesterol, triglycerides and HDL cholesterol were also measured. At baseline and after 24 weeks, bone turn-over markers were also evaluated. After denosumab administration, with the exception of a slight reduction of insulin and HOMA-IR values after 4 weeks (p < 0.05), neither fasting plasma glucose nor insulin and insulin resistance were significantly changed. Lipid parameters remained unchanged at each time-points of this study. A reduction of C-telopeptide of type 1 collagen (-63%, p < 0.0001) and osteocalcin (-45%, p < 0.0001), as bone resorption and formation markers, respectively, were observed after 24 weeks. Baseline levels of bone biomarkers were not predictive of HOMA-IR, and changes of osteocalcin were not associated to markers of glucose control. In osteoporotic otherwise healthy postmenopausal women, denosumab was not associated with relevant modification of insulin resistance and lipid profile.