A comparative blind study between skin biopsy and seed amplification assay to disclose pathological α-synuclein in RBD

To compare the diagnostic accuracy of the immunofluorescence (IF) technique and aSyn-seed amplification assay (aSyn-SAA) of skin and cerebrospinal fluid (CSF) in disclosing pathological α-syn in idiopathic idiopathic REM sleep behavior disorder (iRBD) as early phase of a synucleinopathy. We prospectively recruited 41 patients with iRBD and 40 matched clinical controls including RBD associated with type 1 Narcolepsy (RBD-NT1, 21 patients), iatrogenic causes (2 pt) or OSAS (6 pt) and 11 patients with peripheral neuropathies. IF from samples taken by skin biopsy and aSyn-SAA from skin and CSF samples were analysed blinded to the clinical diagnosis. IF showed a good diagnostic accuracy (89%) that was lower in the case of skin and CSF-based aSyn-SAA (70% and 69%, respectively) because of a lower sensitivity and specificity. However, IF showed a significant agreement with CSF aSyn-SAA. In conclusion, our data may favor the use of skin biopsy and aSyn-SAA as diagnostic tools for a synucleinopathy in iRBD.

Consistent skin α-synuclein positivity in REM sleep behavior disorder - A two center two-to-four-year follow-up study

OBJECTIVE/METHODS

Phosphorylated alpha-synuclein (p-syn) in dermal nerves of patients with isolated REM sleep behavior disorder (iRBD) is detectable by immunofluorescence-labeling. Skin-biopsy-p-syn-positivity was recently postulated to be a prodromal marker of Parkinson's disease (PD) or related synucleinopathies. Here, we provide two-to four-year clinical and skin biopsy follow-up data of 33 iRBD patients, whose skin biopsy findings at baseline were reported in 2017.

RESULTS

Follow-up biopsies were available from 25 patients (18 positive at baseline) and showed consistent findings over time in 24 patients. One patient converted from skin-biopsy-negativity to -positivity. P-syn-positivity was observed in iRBD patients who still had a normal FP-CIT-SPECT two years later. Clinically, five of the 23 at baseline skin-biopsy-positive patients (21.7%) had converted to PD or dementia with Lewy bodies at follow-up, but none of the skin-biopsy-negative patients.

CONCLUSIONS

Dermal p-syn in iRBD is most probably an early consistent marker of synucleinopathy and may support other indicators of conversion to manifest disease state.

0941 Defining Disrupted Nighttime Sleep in Pediatric Narcolepsy

Introduction

Disrupted nighttime sleep (DNS) is a core narcolepsy symptom subjectively described as spontaneous awakenings during the night, but researchers use varied polysomnogram (PSG) definitions based on sleep state transitions, NREM 1% and poor sleep efficiency. These sleep measures have yet to be validated to determine the best objective measure of DNS. Furthermore, it unknown to what extent DNS occurs in pediatric narcolepsy as children have greater sleep drive than adults. Here, we assess the construct validity of various DNS objective measures and evaluate its diagnostic utility for pediatric Narcolepsy Type 1 (NT1) when combined with a nocturnal Sleep Onset REM period (nSOREMP) in a large cohort of pediatric patients with CNS hypersomnias.

Methods

Retrospective, cross-sectional study of consecutive PSGs and multiple sleep latency tests (MSLTs) obtained at Boston Children’s Hospital and University of Bologna. Participants were drug-free or drug naïve, ages 6-18 years and slept at least 6 hours during the PSG. We analyzed associations between objective DNS measures and outcomes of self-reported sleep disturbance, Epworth Sleepiness Score, mean sleep latency, NT1 diagnosis, and CSF hypocretin values when available. We then combined the best performing DNS measure with the presence of a nSOREMP to determine the diagnostic value for NT1 using bootstrap analysis. We included n=151 NT1, n=21 narcolepsy type 2 (NT2), n=27 idiopathic hypersomnia (IH) and n= 117 subjectively sleepy controls in this analysis.

Results

Across groups, the Wake and NREM 1 bouts index had the most robust associations with objective sleepiness, subjective sleep disturbance and CSF hypocretin levels (p’s <0.0001). From 1000 bootstrap samples, the Wake/N1 index and presence of a nSOREMP have greater diagnostic accuracy for NT1 than the nSOREMP alone (p<0.0001).

Conclusion

Among a variety of sleep quality measures, we find that a Wake and NREM 1 bout index is the best objective measure of DNS. In combination with a nSOREMP, this DNS measure can aid in pediatric NT1 diagnosis using PSG alone and potentially reduce diagnostic delays.

Support

This study was supported by K23 National Institutes of Health (NINDS, K23 NS104267-01A1) grant and Investigator Initiated Research grant from Jazz Pharmaceuticals, Inc. to Dr. Maski

Abnormal α-synuclein deposits in skin nerves: intra- and inter-laboratory reproducibility

BACKGROUND AND PURPOSE

Visualization of phosphorylated α-synuclein at serine 129 (p-syn) in skin nerves is a promising test for the in vivo diagnosis of synucleinopathies. Here the aim was to establish the intra- and inter-laboratory reproducibility of measurement of intraneural p-syn immunoreactivity in two laboratories with major expertise (Würzburg and Bologna).

METHODS

In total, 43 patients affected by Parkinson's disease (PD 21 patients), dementia with Lewy bodies (DLB 1), rapid eye movement sleep behaviour disorder (RBD 11), multiple system atrophy (MSA-P 4) and small fibre neuropathy (SFN 6) were enrolled. Skin biopsy was performed at the C7 paravertebral spine region and distal skin sites (thigh or leg). The analysis was standardized in both laboratories and carried out blinded on a single skin section double stained with antibodies to p-syn and the pan-axonal marker protein gene product 9.5. Fifty skin sections were randomly selected for the analysis: 25 from C7 and 25 from distal sites. Differently classified sections were re-evaluated to understand the reasons for the discrepancy.

RESULTS

The intra-laboratory analysis showed an excellent reproducibility both in Würzburg (concordance of classification 100% of sections; K = 1; P < 0.001) and Bologna (96% of sections; K = 0.92; P < 0.001). Inter-laboratory analysis showed reproducibility in 45 sections (90%; K = 0.8; P < 0.001) and a different classification in five sections, which was mainly due to fragmented skin samples or weak fluorescent signals.

CONCLUSIONS

Analysis of p-syn showed excellent inter- and intra-laboratory reproducibility supporting the reliability of this technique. The few ascertained discordances were important to further improve the standardization of this technique.

Red Flags for early referral of people with symptoms suggestive of narcolepsy: a report from a national multidisciplinary panel

OBJECTIVE

Narcolepsy is a lifelong disease, manifesting with excessive daytime sleepiness and cataplexy, arising between childhood and young adulthood. The diagnosis is typically made after a long delay that burdens the disease severity. The aim of the project, promoted by the "Associazione Italiana Narcolettici e Ipersonni" is to develop Red Flags to detect symptoms for early referral, targeting non-sleep medicine specialists, general practitioners, and pediatricians.

MATERIALS AND METHODS

A multidisciplinary panel, including patients, public institutions, and representatives of national scientific societies of specialties possibly involved in the diagnostic process of suspected narcolepsy, was convened. The project was accomplished in three phases. Phase 1: Sleep experts shaped clinical pictures of narcolepsy in pediatric and adult patients. On the basis of these pictures, Red Flags were drafted. Phase 2: Representatives of the scientific societies and patients filled in a form to identify barriers to the diagnosis of narcolepsy. Phase 3: The panel produced suggestions for the implementation of Red Flags.

RESULTS

Red Flags were produced representing three clinical pictures of narcolepsy in pediatric patients ((1) usual sleep symptoms, (2) unusual sleep symptoms, (3) endocrinological signs) and two in adult patients ((1) usual sleep symptoms, (2) unusual sleep symptoms). Inadequate knowledge of symptoms at onset by medical doctors turned out to be the main reported barrier to diagnosis.

CONCLUSIONS

This report will hopefully enhance knowledge and awareness of narcolepsy among non-specialists in sleep medicine in order to reduce the diagnostic delay that burdens patients in Italy. Similar initiatives could be promoted across Europe.

Phospho-TCTP as a therapeutic target of Dihydroartemisinin for aggressive breast cancer cells

Upregulation of Translationally Controlled Tumor Protein (TCTP) is associated with poorly differentiated aggressive tumors, including breast cancer, but the underlying mechanism(s) are still debated. Here, we show that in breast cancer cell lines TCTP is primarily localized in the nucleus, mostly in the phosphorylated form.

The effects of Dihydroartemisinin (DHA), an anti-malaria agent that binds TCTP, were tested on breast cancer cells. DHA decreases cell proliferation and induces apoptotic cell death by targeting the phosphorylated form of TCTP. Remarkably, DHA enhances the anti-tumor effects of Doxorubicin in triple negative breast cancer cells resulting in an increased level of apoptosis. DHA also synergizes with Trastuzumab, used to treat HER2/neu positive breast cancers, to induce apoptosis of tumor cells.

Finally, we present new clinical data that nuclear phospho-TCTP overexpression in primary breast cancer tissue is associated with high histological grade, increase expression of Ki-67 and with ER-negative breast cancer subtypes. Notably, phospho-TCTP expression levels increase in trastuzumab-resistant breast tumors, suggesting a possible role of phospho-TCTP as a new prognostic marker.

In conclusion, the anti-tumor effect of DHA in vitro with conventional chemotherapeutics suggests a novel therapeutic strategy and identifies phospho-TCTP as a new promising target for advanced breast cancer.

The role of cerebellum in patients with late onset cervical/segmental dystonia?--evidence from the clinic

BACKGROUND

There is evidence from animal studies, post-mortem pathology, functional imaging and neurophysiological studies to suggest that the cerebellum may be involved in the pathophysiology of dystonia. We sought to explore further the association of clinical and radiological abnormalities of the cerebellum in patients with dystonia.

METHODS

We retrospectively reviewed patients from our movement disorders research database, with predominant cervical dystonia who have been seen within last 6 months and had available routine magnetic resonance imaging (MRI). The clinical details including presence of cerebellar signs, imaging findings and results of investigations were recorded on a proforma. The results were analysed using percentages and means with standard deviation.

RESULTS

Out of 188 patients included 26 had evidence of cerebellar abnormality on neuroimaging. 17 patients showed cerebellar atrophy and 10 of these had cerebellar signs on examination. These patients were tested negative for common inherited ataxias. 9 patients had cerebellar lesions on MRI, reported as low grade tumour (n = 2), cerebellar infarct (n = 3), cyst (n = 2), white matter hyperintensity (n = 1) and ectopia (n = 1) out of these 4 had cerebellar signs.

CONCLUSION

The findings from our study suggest that there may be overt clinical or radiological cerebellar involvement in 14% of cases with cervical/segmental dystonia. However, larger prospective studies are needed in this context.

Protease activity at invadopodial focal digestive areas is dependent on NHE1-driven acidic pHe

Degradation of the extracellular matrix (ECM) is a critical step of tumor cell invasion and requires protease-dependent proteolysis focalized at the invadopodia where the proteolysis of the ECM occurs. Most of the extracellular proteases belong to serine- or metallo-proteases and the invadopodia is where protease activity is regulated. While recent data looking at global protease activity in the growth medium reported that their activity and role in invasion is dependent on Na+/H+ exchanger 1 (NHE1)-driven extracellular acidification, there is no data on this aspect at the invadopodia, and an open question remains whether this acid extracellular pH (pHe) activation of proteases in tumor cells occurs preferentially at invadopodia. We previously reported that the NHE1 is expressed in breast cancer invadopodia and that the NHE1‑dependent acidification of the peri-invadopodial space is critical for ECM proteolysis. In the present study, using, for the first time, in situ zymography analysis, we demonstrated a concordance between NHE1 activity, extracellular acidification and protease activity at invadopodia to finely regulate ECM digestion. We demonstrated that: (i) ECM proteolysis taking place at invadopodia is driven by acidification of the peri-invadopodia microenvironment; (ii) that the proteases have a functional pHe optimum that is acidic; (iii) more than one protease is functioning to digest the ECM at these invadopodial sites of ECM proteolysis; and (iv) lowering pHe or inhibiting the NHE1 increases protease secretion while blocking protease activity changes NHE1 expression at the invadopodia.

ß1 integrin binding phosphorylates ezrin at T567 to activate a lipid raft signalsome driving invadopodia activity and invasion

Extracellular matrix (ECM) degradation is a critical process in tumor cell invasion and requires matrix degrading protrusions called invadopodia. The Na⁺/H⁺ exchanger (NHE1) has recently been shown to be fundamental in the regulation of invadopodia actin cytoskeleton dynamics and activity. However, the structural link between the invadopodia cytoskeleton and NHE1 is still unknown. A candidate could be ezrin, a linker between the NHE1 and the actin cytoskeleton known to play a pivotal role in invasion and metastasis. However, the mechanistic basis for its role remains unknown. Here, we demonstrate that ezrin phosphorylated at T567 is highly overexpressed in the membrane of human breast tumors and positively associated with invasive growth and HER2 overexpression. Further, in the metastatic cell line, MDA-MB-231, p-ezrin was almost exclusively expressed in invadopodia lipid rafts where it co-localized in a functional complex with NHE1, EGFR, ß1-integrin and phosphorylated-NHERF1. Manipulation by mutation of ezrins T567 phosphorylation state and/or PIP2 binding capacity or of NHE1s binding to ezrin or PIP2 demonstrated that p-ezrin expression and binding to PIP2 are required for invadopodia-mediated ECM degradation and invasion and identified NHE1 as the membrane protein that p-ezrin regulates to induce invadopodia formation and activity.

NaV1.5 Na⁺ channels allosterically regulate the NHE-1 exchanger and promote the activity of breast cancer cell invadopodia

The degradation of the extracellular matrix by cancer cells represents an essential step in metastatic progression and this is performed by cancer cell structures called invadopodia. NaV1.5 (also known as SCN5A) Na(+) channels are overexpressed in breast cancer tumours and are associated with metastatic occurrence. It has been previously shown that NaV1.5 activity enhances breast cancer cell invasiveness through perimembrane acidification and subsequent degradation of the extracellular matrix by cysteine cathepsins. Here, we show that NaV1.5 colocalises with Na(+)/H(+) exchanger type 1 (NHE-1) and caveolin-1 at the sites of matrix remodelling in invadopodia of MDA-MB-231 breast cancer cells. NHE-1, NaV1.5 and caveolin-1 co-immunoprecipitated, which indicates a close association between these proteins. We found that the expression of NaV1.5 was responsible for the allosteric modulation of NHE-1, rendering it more active at the intracellular pH range of 6.4-7; thus, it potentially extrudes more protons into the extracellular space. Furthermore, NaV1.5 expression increased Src kinase activity and the phosphorylation (Y421) of the actin-nucleation-promoting factor cortactin, modified F-actin polymerisation and promoted the acquisition of an invasive morphology in these cells. Taken together, our study suggests that NaV1.5 is a central regulator of invadopodia formation and activity in breast cancer cells.

NHERF1 acts as a molecular switch to program metastatic behavior and organotropism via its PDZ domains

Tumor metastasis is the primary cause of death in cancer patients, but the molecular mechanisms driving the evolution of the phenotype toward a specific organ is one of its less understood aspects. The scaffolding protein NHERF1 reprograms the metastatic phenotype and organotropism via the differential function of its PDZ domains.

Metastatic cells are highly plastic for differential expression of tumor phenotype hallmarks and metastatic organotropism. The signaling proteins orchestrating the shift of one cell phenotype and organ pattern to another are little known. Na⁺/H⁺ exchanger regulatory factor (NHERF1) is a molecular pathway organizer, PDZ-domain protein that recruits membrane, cytoplasmic, and cytoskeletal signaling proteins into functional complexes. To gain insight into the role of NHERF1 in metastatic progression, we stably transfected a metastatic breast cell line, MDA-MB-231, with an empty vector, with wild-type NHERF1, or with NHERF1 mutated in either the PDZ1- or PDZ2-binding domains to block their binding activities. We observed that NHERF1 differentially regulates the expression of two phenotypic programs through its PDZ domains, and these programs form the mechanistic basis for metastatic organotropism. The PDZ2 domain promotes visceral metastases via increased invadopodia-dependent invasion and anchorage-independent growth, as well as by inhibition of apoptosis, whereas the PDZ1 domain promotes bone metastases by stimulating podosome nucleation, motility, neoangiogenesis, vasculogenic mimicry, and osteoclastogenesis in the absence of increased growth or invasion. Collectively, these findings identify NHERF1 as an important signaling nexus for coordinating cell structure with metastatic behavior and identifies the “mesenchymal-to-vasculogenic” phenotypic transition as an essential step in metastatic progression.

NHE1 promotes invadopodial ECM proteolysis through acidification of the peri-invadopodial space

Extracellular matrix (ECM) degradation is a critical process in tumor cell invasion and requires membrane and released proteases focalized at membrane structures called invadopodia. While extracellular acidification is important in driving tumor invasion, the structure/function mechanisms underlying this regulation are still unknown. Invadopodia are similar in structure and function to osteoclast podosomes responsible for bone degradation, and extracellular acidification is central to podosome action, suggesting that it could also be for invadopodial function. Here, utilizing a novel system for in situ zymography in native matrices, we show that the Na(+)/H(+) exchanger (NHE1) and NHE1-generated extracellular acidification are localized at and necessary for invadopodial-dependent ECM degradation, thereby promoting tumor invasion. Stimulation with EGF increased both NHE1-dependent proton secretion and ECM degradation. Manipulation of the NHE1 expression by RNA interference or activity via either transport-deficient mutation or the specific inhibitor cariporide confirmed that NHE1 expression and activity are required for invadopodia-mediated ECM degradation. Taken together, our data show a concordance among NHE1 localization, the generation of a well-defined acidic extracellular pH in the nanospace surrounding invadopodia, and matrix-degrading activity at invadopodia of human malignant breast carcinoma cells, providing a structural basis for the role of NHE1 in invasion and identifying NHE1 as a strategic target for therapeutic intervention.