CAG repeat mosaicism is gene specific in spinocerebellar ataxias

Expanded CAG repeats in coding regions of different genes are the most common cause of dominantly inherited spinocerebellar ataxias (SCAs). These repeats are unstable through the germline, and larger repeats lead to earlier onset. We measured somatic expansion in blood samples collected from 30 SCA1, 50 SCA2, 74 SCA3, and 30 SCA7 individuals over a mean interval of 8.5 years, along with postmortem tissues and fetal tissues from SCA1, SCA3, and SCA7 individuals to examine somatic expansion at different stages of life. We showed that somatic mosaicism in the blood increases over time. Expansion levels are significantly different among SCAs and correlate with CAG repeat lengths. The level of expansion is greater in individuals with SCA7 who manifest disease compared to that of those who do not yet display symptoms. Brain tissues from SCA individuals have larger expansions compared to the blood. The cerebellum has the lowest mosaicism among the studied brain regions, along with a high expression of ATXNs and DNA repair genes. This was the opposite in cortices, with the highest mosaicism and lower expression of ATXNs and DNA repair genes. Fetal cortices did not show repeat instability. This study shows that CAG repeats are increasingly unstable during life in the blood and the brain of SCA individuals, with gene- and tissue-specific patterns.

A developmental component to Huntington's disease

Huntington's disease is a dominantly inherited disorder characterized by the dysfunction and death of cortical and striatal neurons. Striatal degeneration in Huntington's disease is due, at least in part, to defective cortical signalling to the striatum. Although Huntington's disease generally manifests at the adult stage, mouse and neuroimaging studies of presymptomatic mutation carriers suggest that it may affect neurodevelopment. In support of this notion, the development of the cortex is altered in mice with Huntington's disease and the foetuses of human Huntington's disease gene carriers. We will discuss these studies and the contribution of abnormal brain development to the later appearance of the disease.

Pregnancy outcome in patients with a medical history of immunoglobulin A vasculitis: a case-control study

OBJECTIVE

Data on obstetric outcomes in patients with a history of immunoglobulin A vasculitis (IgA-V) are lacking. The aim of this study was to assess maternal, neonatal, and vasculitis outcomes during pregnancy.

METHOD

We conducted a French retrospective case-control study. Pregnancies of patients with a history of IgA-V (cases) were retrospectively studied and compared to pregnancies in women who developed IgA-V after their pregnancies and to pregnancies in healthy women (controls).

RESULTS

Twenty-six pregnancies in patients with a history of IgA-V were included and compared to 15 pregnancies in women who later developed IgA-V and 52 pregnancies in healthy women. Both gestational hypertension and pre-eclampsia were more frequent in the case group than in the other groups (23% vs 0% vs 0%, p < 0.01; 12% vs 7% vs 0%, p = 0.04). Hypertensive disorder of pregnancy occurred more frequently in patients with pre-existing kidney disease (78% vs 12%, p < 0.01). Caesarean section was more often performed in the case group than in the other groups (27% vs 0% vs 10%, p = 0.04). No foetal loss or maternal deaths occurred. There were no differences in delivery term or birth weight. No vasculitis flares were observed during pregnancy.

CONCLUSION

Women with a history of IgA-V appear to be at higher risk for gestational hypertension and pre-eclampsia, especially in cases with renal involvement; however, both mother and newborn outcomes appear to be favourable.

Customization of the translational complex regulates mRNA-specific translation to control CNS regeneration

In the adult mammalian central nervous system (CNS), axons fail to regenerate spontaneously after injury because of a combination of extrinsic and intrinsic factors. Despite recent advances targeting the intrinsic regenerative properties of adult neurons, the molecular mechanisms underlying axon regeneration are not fully understood. Here, we uncover a regulatory mechanism that controls the expression of key proteins involved in regeneration at the translational level. Our results show that mRNA-specific translation is critical for promoting axon regeneration. Indeed, we demonstrate that specific ribosome-interacting proteins, such as the protein Huntingtin (HTT), selectively control the translation of a specific subset of mRNAs. Moreover, modulating the expression of these translationally regulated mRNAs is crucial for promoting axon regeneration. Altogether, our findings highlight that selective translation through the customization of the translational complex is a key mechanism of axon regeneration with major implications in the development of therapeutic strategies for CNS repair.

Huntington's disease and brain development

Huntington's disease is a rare inherited neurological disorder that generally manifests in mild-adulthood. The disease is characterized by the dysfunction and the degeneration of specific brain structures leading progressively to psychiatric, cognitive and motor disorders. The disease is caused by a mutation in the gene coding for huntingtin and, although it appears in adulthood, embryos carry the mutated gene from their development in utero. Studies based on mouse models and human stem cells have reported altered developmental mechanisms in disease conditions. However, does the mutation affect development in humans? Focusing on the early stages of brain development in human fetuses carrying the HD mutation, we have identified abnormalities in the development of the neocortex, the structure that ensure higher cerebral functions. Altogether, these studies suggests that developmental defects could contribute to the onset symptoms in adults, changing the perspective on disease and thus the health care of patients.

Huntingtin regulates calcium fluxes in skeletal muscle

The expression of the Huntingtin protein, well known for its involvement in the neurodegenerative Huntington's disease, has been confirmed in skeletal muscle. The impact of HTT deficiency was studied in human skeletal muscle cell lines and in a mouse model with inducible and muscle-specific HTT deletion. Characterization of calcium fluxes in the knock-out cell lines demonstrated a reduction in excitation-contraction (EC) coupling, related to an alteration in the coupling between the dihydropyridine receptor and the ryanodine receptor, and an increase in the amount of calcium stored within the sarcoplasmic reticulum, linked to the hyperactivity of store-operated calcium entry (SOCE). Immunoprecipitation experiments demonstrated an association of HTT with junctophilin 1 (JPH1) and stromal interaction molecule 1 (STIM1), both providing clues on the functional effects of HTT deletion on calcium fluxes. Characterization of muscle strength and muscle anatomy of the muscle-specific HTT-KO mice demonstrated that HTT deletion induced moderate muscle weakness and mild muscle atrophy associated with histological abnormalities, similar to the phenotype observed in tubular aggregate myopathy. Altogether, this study points toward the hypotheses of the involvement of HTT in EC coupling via its interaction with JPH1, and on SOCE via its interaction with JPH1 and/or STIM1.

Longitudinal multimodal MRI characterization of a knock-in mouse model of Huntington's disease reveals early gray and white matter alterations

Pathogenesis of the inherited neurodegenerative disorder Huntington's disease (HD) is progressive with a long presymptomatic phase in which subtle changes occur up to 15 years before the onset of symptoms. Thus, there is a need for early, functional biomarker to better understand disease progression and to evaluate treatment efficacy far from onset. Recent studies have shown that white matter may be affected early in mutant HTT gene carriers. A previous study performed on 12 months old Ki140CAG mice showed reduced glutamate level measured by Chemical Exchange Saturation Transfer of glutamate (gluCEST), especially in the corpus callosum. In this study, we scanned longitudinally Ki140CAG mice with structural MRI, diffusion tensor imaging, gluCEST and magnetization transfer imaging, in order to assess white matter integrity over the life of this mouse model characterized by slow progression of symptoms. Our results show early defects of diffusion properties in the anterior part of the corpus callosum at 5 months of age, preceding gluCEST defects in the same region at 8 and 12 months that spread to adjacent regions. At 12 months, frontal and piriform cortices showed reduced gluCEST, as well as the pallidum. MT imaging showed reduced signal in the septum at 12 months. Cortical and striatal atrophy then appear at 18 months. Vulnerability of the striatum and motor cortex, combined with alterations of anterior corpus callosum, seems to point out the potential role of white matter in the brain dysfunction that characterizes HD and the pertinence of gluCEST and DTI as biomarkers in HD.

Treating early postnatal circuit defect delays Huntington's disease onset and pathology in mice

Recent evidence has shown that even mild mutations in the Huntingtin gene that are associated with late-onset Huntington's disease (HD) disrupt various aspects of human neurodevelopment. To determine whether these seemingly subtle early defects affect adult neural function, we investigated neural circuit physiology in newborn HD mice. During the first postnatal week, HD mice have less cortical layer 2/3 excitatory synaptic activity than wild-type mice, express fewer glutamatergic receptors, and show sensorimotor deficits. The circuit self-normalizes in the second postnatal week but the mice nonetheless develop HD. Pharmacologically enhancing glutamatergic transmission during the neonatal period, however, rescues these deficits and preserves sensorimotor function, cognition, and spine and synapse density as well as brain region volume in HD adult mice.

Huntingtin coordinates dendritic spine morphology and function through cofilin-mediated control of the actin cytoskeleton

Compelling evidence indicates that in Huntington's disease (HD), mutation of huntingtin (HTT) alters several aspects of early brain development such as synaptogenesis. It is not clear to what extent the partial loss of wild-type HTT function contributes to these abnormalities. Here we investigate the function of HTT in the formation of spines. Although larger spines normally correlate with more synaptic activity, cell-autonomous depletion of HTT leads to enlarged spines but reduced excitatory synaptic function. We find that HTT is required for the proper turnover of endogenous actin and to recruit AMPA receptors at active synapses; loss of HTT leads to LIM kinase (LIMK) hyperactivation, which maintains cofilin in its inactive state. HTT therefore influences actin dynamics through the LIMK-cofilin pathway. Loss of HTT uncouples spine structure from synaptic function, which may contribute to the ultimate development of HD symptoms.

A pathogenic proteolysis-resistant huntingtin isoform induced by an antisense oligonucleotide maintains huntingtin function

Huntington’s disease (HD) is a late-onset neurological disorder for which therapeutics are not available. Its key pathological mechanism involves the proteolysis of polyglutamine-expanded (polyQ-expanded) mutant huntingtin (mHTT), which generates N-terminal fragments containing polyQ, a key contributor to HD pathogenesis. Interestingly, a naturally occurring spliced form of HTT mRNA with truncated exon 12 encodes an HTT (HTT^Δ12) with a deletion near the caspase-6 cleavage site. In this study, we used a multidisciplinary approach to characterize the therapeutic potential of targeting HTT exon 12. We show that HTT^Δ12 was resistant to caspase-6 cleavage in both cell-free and tissue lysate assays. However, HTT^Δ12 retained overall biochemical and structural properties similar to those of wt-HTT. We generated mice in which HTT exon 12 was truncated and found that the canonical exon 12 was dispensable for the main physiological functions of HTT, including embryonic development and intracellular trafficking. Finally, we pharmacologically induced HTT^Δ12 using the antisense oligonucleotide (ASO) QRX-704. QRX-704 showed predictable pharmacology and efficient biodistribution. In addition, it was stable for several months and inhibited pathogenic proteolysis. Furthermore, QRX-704 treatments resulted in a reduction of HTT aggregation and an increase in dendritic spine count. Thus, ASO-induced HTT exon 12 splice switching from HTT may provide an alternative therapeutic strategy for HD.

Calcineurin and huntingtin form a calcium-sensing machinery that directs neurotrophic signals to the nucleus

When a neurotrophin binds at the presynapse, it sends survival signals all the way to the nucleus on signaling endosomes. These endosomes fuel their own journey with on-board glycolysis—but how is that journey initiated and maintained? Using microfluidic devices and mice, we find that the calcium released upon brain-derived neurotrophic factor (BDNF) binding to its receptor, tropomyosin receptor kinase B (TrkB), is sensed by calcineurin on the cytosolic face of the endosome. Calcineurin dephosphorylates huntingtin, the BDNF scaffold, which sets the endosome moving in a retrograde direction. In an in vitro reconstituted microtubule transport system, controlled calcium uncaging prompts purified vesicles to move to the microtubule minus end. We observed similar retrograde waves of TrkA- and epidermal growth factor receptor (EGFR)-bearing endosomes. Signaling endosomes in neurons thus carry not only their own fuel, but their own navigational system.

Further characterization of clinical and laboratory features occurring in VEXAS syndrome in a large-scale analysis of multicenter case-series of 116 French patients

BACKGROUND

A new autoinflammatory syndrome related to somatic mutations of UBA1 was recently described and called VEXAS syndrome.

OBJECTIVE

To describe clinical characteristics, laboratory findings and outcomes of VEXAS syndrome.

DESIGN

Case-series.

SETTING

Patients referred to a French multicenter registry between November 2020 and May 2021.

PATIENTS

116 patients with VEXAS syndrome.

MEASUREMENTS

Frequency and median of parameters and vital status, from diagnosis to the end of the follow-up.

RESULTS

Main clinical features were skin lesions (83.5%), non-infectious fever (63.6%), weight loss (62%), lung involvement (49.6%), ocular symptoms (38.8%), relapsing chondritis (36.4%), venous thrombosis (34.7%), lymph nodes (33.9%), and arthralgia (27.3%). Hematological disease was present in 58 cases (50%), considered as myelodysplastic syndrome (MDS, n= 58) and monoclonal gammapathy of unknown significance (n=12).UBA1 mutations included p.M41T (44.8%), p.M41V (30.2%), p.M41L (18.1%), and splice mutations (6.9%). After a median follow-up of 3.0 years, 18 patients died (15.5%), from infectious origin (n=9) and MDS progression (n=3). Unsupervised analysis identified 3 clusters: cluster 1 (47%) with mild-to-moderate disease; cluster 2 (16%) with underlying MDS and higher mortality rates; cluster 3 (37%) with constitutional manifestations, higher C-reactive protein levels and less frequent chondritis. Five-year probability of survival was 84.2% in cluster 1, 50.5 % in cluster 2, and 89.6% in cluster 3. UBA1 p.Met41Leu mutation was associated with a better prognosis.

CONCLUSION

VEXAS syndrome displays a large spectrum of organ manifestations and shows different clinical and prognostic profiles. It also raises a potential impact of the identified UBA1 mutation.

Propensity for somatic expansion increases over the course of life in Huntington disease

Recent work on Huntington disease (HD) suggests that somatic instability of CAG repeat tracts, which can expand into the hundreds in neurons, explains clinical outcomes better than the length of the inherited allele. Here, we measured somatic expansion in blood samples collected from the same 50 HD mutation carriers over a twenty-year period, along with post-mortem tissue from 15 adults and 7 fetal mutation carriers, to examine somatic expansions at different stages of life. Post-mortem brains, as previously reported, had the greatest expansions, but fetal cortex had virtually none. Somatic instability in blood increased with age, despite blood cells being short-lived compared to neurons, and was driven mostly by CAG repeat length, then by age at sampling and by interaction between these two variables. Expansion rates were higher in symptomatic subjects. These data lend support to a previously proposed computational model of somatic instability-driven disease.

Chronic Corticosterone Elevation Suppresses Adult Hippocampal Neurogenesis by Hyperphosphorylating Huntingtin

Chronic exposure to stress is a major risk factor for neuropsychiatric disease, and elevated plasma corticosterone (CORT) correlates with reduced levels of both brain-derived neurotrophic factor (BDNF) and hippocampal neurogenesis. Precisely how these phenomena are linked, however, remains unclear. Using a cortico-hippocampal network-on-a-chip, we find that the glucocorticoid receptor agonist dexamethasone (DXM) stimulates the cyclin-dependent kinase 5 (CDK5) to phosphorylate huntingtin (HTT) at serines 1181 and 1201 (S1181/1201), which retards BDNF vesicular transport in cortical axons. Parallel studies in mice show that CORT induces phosphorylation of these same residues, reduces BDNF levels, and suppresses neurogenesis. The adverse effects of CORT are reduced in mice bearing an unphosphorylatable mutant HTT (Hdh^{S1181A/S1201A}). The protective effect of unphosphorylatable HTT, however, disappears if neurogenesis is blocked. The CDK5-HTT pathway, which regulates BDNF transport in the cortico-hippocampal network, thus provides a missing link between elevated CORT levels and suppressed neurogenesis.

Recreating mouse cortico-hippocampal neuronal circuit in microfluidic devices to study BDNF axonal transport upon glucocorticoid treatment

BDNF levels are reduced in the chronically stressed brain, in the area of hippocampus. Part of the hippocampal BDNF is provided by neuronal projection of the entorhinal cortex. Studying the cortico-hippocampal transport of BDNF in vivo is technically difficult. Here, we describe a protocol that reproduces mouse cortico-hippocampal circuit in vitro by plating neurons on the microfluidic devices and infecting the neurons with virus-encoding BDNF-mCherry, which allows investigation of the effects of elevated corticosterone levels on BDNF axonal transport.

For complete details on the use and execution of this protocol, please refer to Agasse et al. (2020).

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A detailed protocol to produce microfluidic devices modeling neuronal circuit

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Preparation and plating of mouse neurons into microfluidic devices

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Dexamethasone application to mimic chronic stress in neuronal cultures

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Guidelines to record and analyze the dynamics of BDNF vesicles in axons

Increasing brain palmitoylation rescues behavior and neuropathology in Huntington disease mice

Huntington disease (HD) damages the corticostriatal circuitry in large part by impairing transport of brain-derived neurotrophic factor (BDNF). We hypothesized that improving vesicular transport of BDNF could slow or prevent disease progression. We therefore performed selective proteomic analysis of vesicles transported within corticostriatal projecting neurons followed by in silico screening and identified palmitoylation as a pathway that could restore defective huntingtin-dependent trafficking. Using a synchronized trafficking assay and an HD network-on-a-chip, we found that increasing brain palmitoylation via ML348, which inhibits the palmitate-removing enzyme acyl-protein thioesterase 1 (APT1), restores axonal transport, synapse homeostasis, and survival signaling to wild-type levels without toxicity. In human HD induced pluripotent stem cell-derived cortical neurons, ML348 increased BDNF trafficking. In HD knock-in mice, it efficiently crossed the blood-brain barrier to restore palmitoylation levels and reverse neuropathology, locomotor deficits, and anxio-depressive behaviors. APT1 and its inhibitor ML348 thus hold therapeutic interest for HD.

Huntington's disease alters human neurodevelopment

Although Huntington's disease is a late-manifesting neurodegenerative disorder, both mouse studies and neuroimaging studies of presymptomatic mutation carriers suggest that Huntington's disease might affect neurodevelopment. To determine whether this is actually the case, we examined tissue from human fetuses (13 weeks gestation) that carried the Huntington's disease mutation. These tissues showed clear abnormalities in the developing cortex, including mislocalization of mutant huntingtin and junctional complex proteins, defects in neuroprogenitor cell polarity and differentiation, abnormal ciliogenesis, and changes in mitosis and cell cycle progression. We observed the same phenomena in Huntington's disease mouse embryos, where we linked these abnormalities to defects in interkinetic nuclear migration of progenitor cells. Huntington's disease thus has a neurodevelopmental component and is not solely a degenerative disease.

Does type of immunosupression influence the course of Covid-19 infection?

Coronavirus disease 19 (Covid-19) is a new emerging virus responsible for pandemic and death. High blood pressure, diabetes, obesity have been described as poor prognosis factors. Few data have been reported in patient with immunocompromised status (solid tumor, hematological malignancy, rheumatoid conditions or organ transplant). We evaluated the characteristics of patients, including the outcome, with immunodepression hospitalized in Besancon University hospital (East of France). We wanted to identify if a type of immunosupression influences the course of Covid-19. In a cohort of 80 patients with immunosupression (42 solid tumors, 20 hematological malignancy and 18 non neoplastic immunosupression), poor outcomes (Intensive care unit hospitalization and or deaths) was frequent (38%) and tended to be more frequent in patients with hematological malignancy.

AB1056 SYMPTOMATIC SCLEROSING MESENTERITIS REVEALING ERDHEIM-CHESTER DISEASE: A RARE CONDITION MEDIATED BY BRAF

Background:

Sclerosing Mesenteritis (SM) refers to an entire spectrum of digestive inflammatory disorders. Diagnosis is based on imaging showing an increase of fat attenuation displacing bowel loops and is in most cases non-symptomatic. Several conditions (abdominal trauma/surgery, neoplasia, infectious and inflammatory diseases) are responsible for SM (1). Among neoplasia, Erdheim-Chester disease (ECD) is a rare clonal histiocytosis characterized by long bone involvement, peri-nephric fat infiltration and cardio-vascular involvement associated with compatible histology (2). Biopsy is mandatory to confirm tissue infiltration by histiocytes and detect somatic mutation. Almost 80% of ECDpatients harbor mutation in mitogen activated protein(MAP) kinase pathway especiallyBRAFV600Egene mutation in about 60% of cases(3). No series of patients presenting both pathologies has been reported. Furthermore, no correlation withBRAFmutation status has been described in patient harboring SM and ECD.

Objectives:

To describe the clinical, radiological and mutational status of patients harboring SM and ECD.

Methods:

We reviewed the database of patients with histiocytic disorders in Besancon University Hospital. Patient required one abdominal computed tomography showing sclerosing mesenteritis and clinical/histological features of ECD to fulfill the inclusion criteria. All biopsy samples were investigated for mutation ofMAPkinase pathway gene.

Results:

Four patients suffered from SM and ECD. The median age at the diagnosis of ECD was 68 years old (61-72). All patients described abdominal pain and the mean duration between first symptoms and diagnosis of ECD was 12 months (4-19). The mean CRP level at diagnosis was 40.75 mg/L (5-117). Two patients were found to have myeloid neoplasms (chronic myelomonocytic leukemia (#2) and essential thrombocythemia (#4)) concurrent with ECD diagnosis.

Regarding abdominal computed tomography, all patients had a mesenteric mass associated with hyper-attenuated mesenteric fat and a “fat halo sign”. One patient (#2) had ascites and one had splenomegaly (#4) but no patient had enlarged lymph nodes. CT also demonstrated peri-nephric fat infiltration (“hairy kidney”) (4/4), vascular sheathing of aortic branches (3/4), adrenal hypertrophy (1/4) or ureter dilation (1/4). The mean SUVmaxof the mesentery was 7.5 (4.1-10.9) at diagnosis on (18F)- fluorodeoxyglucose-PET. Three patients underwent mesentery fat biopsy and all samples exhibited ECD histology. Regarding mutational status, 75% (3/4) patients hadBRAFV600Emutation.

After initiation of therapies for ECD (targeted therapies for ¾ patients), all patients had improvement of digestive symptoms and decreased of SUVmaxon evaluation18FDG-PET during the follow up.

Conclusion:

ECD should be investigated in patient with symptomatic SM especially if it is associated with peri-nephric fat infiltration. This condition is rare and might be driven by BRAF gene.

TABLE 2.Full term pregnancyMultiple gestationPreconception CZP exposureLabor complicationsMaternal infectionsNeonatal infections (< 6 m after birth)Congenital malformationsBreast-feedingNeonates, n/N15/152/155/150/151/150/150/156/15

References:

[1]Danford CJ, Lin SC, Wolf JL. Sclerosing Mesenteritis. Am J Gastroenterol. 2019 Jun;114(6):867–73.

[2]Diamond EL, Dagna L, Hyman DM, Cavalli G, Janku F, Estrada-Veras J, et al. Consensus guidelines for the diagnosis and clinical management of Erdheim-Chester disease. Blood. 2014 Jul 24;124(4):483–92.

[3]Haroche J, Cohen-Aubart F, Rollins BJ, Donadieu J, Charlotte F, Idbaih A, et al. Histiocytoses: emerging neoplasia behind inflammation. Lancet Oncol. 2017 Feb;18(2):e113–25.

Disclosure of Interests:

None declared

Presynaptic APP levels and synaptic homeostasis are regulated by Akt phosphorylation of huntingtin

Studies have suggested that amyloid precursor protein (APP) regulates synaptic homeostasis, but the evidence has not been consistent. In particular, signaling pathways controlling APP transport to the synapse in axons and dendrites remain to be identified. Having previously shown that Huntingtin (HTT), the scaffolding protein involved in Huntington’s disease, regulates neuritic transport of APP, we used a microfluidic corticocortical neuronal network-on-a-chip to examine APP transport and localization to the pre- and post-synaptic compartments. We found that HTT, upon phosphorylation by the Ser/Thr kinase Akt, regulates APP transport in axons but not dendrites. Expression of an unphosphorylatable HTT decreased axonal anterograde transport of APP, reduced presynaptic APP levels, and increased synaptic density. Ablating in vivo HTT phosphorylation in APPPS1 mice, which overexpress APP, reduced presynaptic APP levels, restored synapse number and improved learning and memory. The Akt-HTT pathway and axonal transport of APP thus regulate APP presynaptic levels and synapse homeostasis.

Cancer: From Wild-Type to Mutant Huntingtin

Huntingtin (HTT) is a scaffold protein mostly known because it gives rise to the severe and incurable inherited neurological disorder Huntington’s disease (HD) when mutated. The Huntingtin gene (HTT) carries a polymorphic trinucleotide expansion of CAGs in exon 1 that ranges from 9 to 35 in the non-HD affected population. However, if it exceeds 35 CAG repeats, the altered protein is referred to as mutant HTT and leads to the development of HD. Given the wide spectrum of severe symptoms developed by HD individuals, wild-type and mutant HTT have been mostly studied in the context of this disorder. However, HTT expression is ubiquitous and several peripheral symptoms in HD have been described, suggesting that HTT is of importance, not only in the central nervous system (CNS), but also in peripheral organs. Accordingly, HTT and mutant HTT may interfere with non-brain-related diseases. Correlative studies have highlighted a decreased cancer incidence in the HD population and both wild-type and mutant HTT have been implicated in tumor progression. In this review, we describe the current evidence linking wild-type and mutant HTT to cancer and discuss how CAG polymorphism, HTT function, and partners may influence carcinogenesis and metastatic progression.

P2767Outcomes and incremental prognostic value of renal function impairment after acute pulmonary embolism

Background

We explored the relation between adverse outcomes after acute pulmonary embolism (PE)and renal dysfunction classified by estimated glomerular filtration rate (eGFR) using the CKD-EPI equation. We assessed the incremental value of adding eGFR CKD-EPI to the ESC score for predicting 30d mortality.

Methods

Prospective, multicenter study of 1664 acute PE admitted from 01/2011 to 12/2017. Pts were categorized in 4 eGFR groups: Group 1 (eGFR ≥60 ml/min/1.73m2, n=1178), group 2 (45–59; n=257); group 3 (30–44; n=150), group 4 (≤29; n=79).

Results

All-cause and CV death at 30 days and 6 months were higher in group 3 (p=0.005 and p=0.03) and group 4 (p<0.001 and p<0.001 respectively) vs group 1. Major bleeding at 30d and 6m was higher in group 2 vs group 1 (p=0.003 for both). Renal dysfunction combined with the ESC prognostic algorithm for prediction of 30d death improved discriminatory capacity of the model and enabled reclassification in different risk categories in 27% of pts (Table).

Without eGFR CKD-EPI OR (95% CI) With eGFR CKD-EPI OR (95% CI) ESC algorithm 2.59 (1.95–3.43) 2.30 (1.72–3.07) eGFR CKD-EPI – 2.60 (1.62–4.7) Measures of fit   Bayes information criterion 607.30 599.32   Akaike information criterion 596.47 583.06   C-statistic 0.71* 0.77*   P (Hosmer-Lemeshow) 0.057 0.43   Integrated discrimination improvement – 0.054 (0.052–0.056)   Net reclassification improvement – 0.93 (0.90–0.95) Prognostic performance   Sensitivity 62.5 (51.2–72.3) 76.2 (61.5–90.2)   Specificity 64.2 (49.1–74.4) 69.9 (47.6–83.5)   Positive predictive value 10.1 (8.2–11.3) 16.2 (14.2–18.2)   Negative predictive value 0.97 (0.96–0.98) 98.1 (97.2–99.2)   Positive likelihood ratio 1.96 (1.12–3.41) 2.12 (1.54–3.12)   Negative likelihood ratio 0.50 (0.25–1.81) 0.54 (0.20–1.56)   Youden index 0.31 (0.28–0.34) 0.39 (0.36–0.41) Difference in C-statistic: *p=0.04.

Conclusion

Renal function impairment increases the rate of adverse events after acute PE. Combined with the ESC early mortality risk score, eGFR improves risk classification.

The striatal kinase DCLK3 produces neuroprotection against mutant huntingtin

The neurobiological functions of a number of kinases expressed in the brain are unknown. Here, we report new findings on DCLK3 (doublecortin like kinase 3), which is preferentially expressed in neurons in the striatum and dentate gyrus. Its function has never been investigated. DCLK3 expression is markedly reduced in Huntington's disease. Recent data obtained in studies related to cancer suggest DCLK3 could have an anti-apoptotic effect. Thus, we hypothesized that early loss of DCLK3 in Huntington's disease may render striatal neurons more susceptible to mutant huntingtin (mHtt). We discovered that DCLK3 silencing in the striatum of mice exacerbated the toxicity of an N-terminal fragment of mHtt. Conversely, overexpression of DCLK3 reduced neurodegeneration produced by mHtt. DCLK3 also produced beneficial effects on motor symptoms in a knock-in mouse model of Huntington's disease. Using different mutants of DCLK3, we found that the kinase activity of the protein plays a key role in neuroprotection. To investigate the potential mechanisms underlying DCLK3 effects, we studied the transcriptional changes produced by the kinase domain in human striatal neurons in culture. Results show that DCLK3 regulates in a kinase-dependent manner the expression of many genes involved in transcription regulation and nucleosome/chromatin remodelling. Consistent with this, histological evaluation showed DCLK3 is present in the nucleus of striatal neurons and, protein-protein interaction experiments suggested that the kinase domain interacts with zinc finger proteins, including the transcriptional activator adaptor TADA3, a core component of the Spt-ada-Gcn5 acetyltransferase (SAGA) complex which links histone acetylation to the transcription machinery. Our novel findings suggest that the presence of DCLK3 in striatal neurons may play a key role in transcription regulation and chromatin remodelling in these brain cells, and show that reduced expression of the kinase in Huntington's disease could render the striatum highly vulnerable to neurodegeneration.

Concomitant association of giant cell arteritis and malignancy: a multicenter retrospective case-control study

INTRODUCTION

Some studies suggest that there is an increased risk of malignancies in giant cell arteritis (GCA). We aimed to describe the clinical characteristics and outcomes of GCA patients with concomitant malignancy and compare them to a GCA control group.

METHOD

Patients with a diagnosis of GCA and malignancy and with a maximal delay of 12 months between both diagnoses were retrospectively included in this study and compared to a control group of age-matched (3:1) patients from a multicenter cohort of GCA patients.

RESULTS

Forty-nine observations were collected (median age 76 years). Malignancies comprised 33 (67%) solid neoplasms and 16 (33%) clonal hematologic disorders. No over-representation of a particular type of malignancy was observed. Diagnosis of GCA and malignancy was synchronous in 7 (14%) patients, while malignancy succeeded GCA in 29 (59%) patients. Malignancy was fortuitously diagnosed based on abnormalities observed in laboratory tests in 26 patients, based on imaging in 14 patients, and based on symptoms or clinical examination in the nine remaining patients. Two patients had a concomitant relapse of both conditions. When compared to the control group, patients with concomitant GCA and malignancy were more frequently male (p < 0.001), with an altered general state (p < 0.001), and polymyalgia rheumatica (p < 0.01).

CONCLUSIONS

This study does not indicate an over-representation of any particular type of malignancy in GCA patients. Initial follow-up dictated by vasculitis may have led to an early identification of malignancy. Nevertheless, GCA male patients with an altered general state and polymyalgia rheumatica might more frequently show concomitant malignancies.

[Eosinopenia in 2018]

Since 1893, eosinopenia is a biological test to help a diagnosis of bacterial infection. Several publications have confirmed this hypothesis, particularly in the intensive care, pneumology and pediatric units. The value of this marker has been identified in vascular cerebral diseases and coronary bypass. Its contribution seems as relevant as procalcitonin, without extra cost. The diagnostic performance of this test was reinforced by a composite score (CIBLE score) that may improve its value in daily routine. Finally, monitoring eosinopenia appears to be a reliable mortality marker.