SORL1 is a receptor for tau that promotes tau seeding.

Sortilin-related receptor 1 (SORL1) is an intracellular sorting receptor genetically implicated in Alzheimer's disease (AD) that impacts amyloid precursor protein trafficking. The objective of these studies was to test the hypothesis that SORL1 binds tau, modulates its cellular trafficking and impacts the aggregation of cytoplasmic tau induced by pathological forms of tau. Using surface plasmon resonance measurements, we observed high-affinity binding of tau to SORL1 and the vacuolar protein sorting 10 domain of SORL1. Interestingly, unlike LDL receptor-related protein 1, SORL1 binds tau at both pH 7.4 and pH 5.5, revealing its ability to bind tau at endosomal pH. Immunofluorescence studies confirmed that exogenously added tau colocalized with SORL1 in H4 neuroglioma cells, while overexpression of SORL1 in LDL receptor-related protein 1-deficient Chinese hamster ovary (CHO) cells resulted in a marked increase in the internalization of tau, indicating that SORL1 can bind and mediate the internalization of monomeric forms of tau. We further demonstrated that SORL1 mediates tau seeding when tau RD P301S FRET biosensor cells expressing SORL1 were incubated with high molecular weight forms of tau isolated from the brains of patients with AD. Seeding in H4 neuroglioma cells is significantly reduced when SORL1 is knocked down with siRNA. Finally, we demonstrate that the N1358S mutant of SORL1 significantly increases tau seeding when compared to WT SORL1, identifying for the first time a potential mechanism that connects this specific SORL1 mutation to Alzheimer's disease. Together, these studies identify SORL1 as a receptor that contributes to trafficking and seeding of pathogenic tau.

Regulation of tau internalization, degradation, and seeding by LRP1 reveals multiple pathways for tau catabolism.

In Alzheimer's disease (AD), pathological forms of tau are transferred from cell to cell and "seed" aggregation of cytoplasmic tau. Phosphorylation of tau plays a key role in neurodegenerative tauopathies. In addition, apolipoprotein E (apoE), a major component of lipoproteins in the brain, is a genetic risk determinant for AD. The identification of the apoE receptor, low-density lipoprotein receptor-related protein 1 (LRP1), as an endocytic receptor for tau raises several questions about the role of LRP1 in tauopathies: is internalized tau, like other LRP1 ligands, delivered to lysosomes for degradation, and does LRP1 internalize pathological tau leading to cytosolic seeding? We found that LRP1 rapidly internalizes 125I-labeled tau, which is then efficiently degraded in lysosomal compartments. Surface plasmon resonance experiments confirm high affinity binding of tau and the tau microtubule-binding domain to LRP1. Interestingly, phosphorylated forms of recombinant tau bind weakly to LRP1 and are less efficiently internalized by LRP1. LRP1-mediated uptake of tau is inhibited by apoE, with the apoE4 isoform being the most potent inhibitor, likely because of its higher affinity for LRP1. Employing post-translationally-modified tau derived from brain lysates of human AD brain tissue, we found that LRP1-expressing cells, but not LRP1-deficient cells, promote cytosolic tau seeding in a process enhanced by apoE. These studies identify LRP1 as an endocytic receptor that binds and processes monomeric forms of tau leading to its degradation and promotes seeding by pathological forms of tau. The balance of these processes may be fundamental to the spread of neuropathology across the brain in AD.

Urokinase-type plasminogen activator modulates mammalian circadian clock phase regulation in tissue-type plasminogen activator knockout mice.

Glutamate phase shifts the circadian clock in the mammalian suprachiasmatic nucleus (SCN) by activating NMDA receptors. Tissue-type plasminogen activator (tPA) gates phase shifts by activating plasmin to generate m(ature) BDNF, which binds TrkB receptors allowing clock phase shifts. Here, we investigate phase shifting in tPA knockout (tPA-/- ; B6.129S2-Plattm1Mlg /J) mice, and identify urokinase-type plasminogen activator (uPA) as an additional circadian clock regulator. Behavioral activity rhythms in tPA-/- mice entrain to a light-dark (LD) cycle and phase shift in response to nocturnal light pulses with no apparent loss in sensitivity. When the LD cycle is inverted, tPA-/- mice take significantly longer to entrain than C57BL/6J wild-type (WT) mice. SCN brain slices from tPA-/- mice exhibit entrained neuronal activity rhythms and phase shift in response to nocturnal glutamate with no change in dose-dependency. Pre-treating slices with the tPA/uPA inhibitor, plasminogen activator inhibitor-1 (PAI-1), inhibits glutamate-induced phase delays in tPA-/- slices. Selective inhibition of uPA with UK122 prevents glutamate-induced phase resetting in tPA-/- but not WT SCN slices. tPA expression is higher at night than the day in WT SCN, while uPA expression remains constant in WT and tPA-/- slices. Casein-plasminogen zymography reveals that neither tPA nor uPA total proteolytic activity is under circadian control in WT or tPA-/- SCN. Finally, tPA-/- SCN tissue has lower mBDNF levels than WT tissue, while UK122 does not affect mBDNF levels in either strain. Together, these results suggest that either tPA or uPA can support photic/glutamatergic phase shifts of the SCN circadian clock, possibly acting through distinct mechanisms.

GIRK Channels Mediate the Nonphotic Effects of Exogenous Melatonin.

Melatonin supplementation has been used as a therapeutic agent for several diseases, yet little is known about the underlying mechanisms by which melatonin synchronizes circadian rhythms. G-protein signaling plays a large role in melatonin-induced phase shifts of locomotor behavior and melatonin receptors activate G-protein-coupled inwardly rectifying potassium (GIRK) channels in Xenopus oocytes. The present study tested the hypothesis that melatonin influences circadian phase and electrical activity within the central clock in the suprachiasmatic nucleus (SCN) through GIRK channel activation. Unlike wild-type littermates, GIRK2 knock-out (KO) mice failed to phase advance wheel-running behavior in response to 3 d subcutaneous injections of melatonin in the late day. Moreover, in vitro phase resetting of the SCN circadian clock by melatonin was blocked by coadministration of a GIRK channel antagonist tertiapin-q (TPQ). Loose-patch electrophysiological recordings of SCN neurons revealed a significant reduction in the average action potential rate in response to melatonin. This effect was lost in SCN slices treated with TPQ and SCN slices from GIRK2 KO mice. The melatonin-induced suppression of firing rate corresponded with an increased inward current that was blocked by TPQ. Finally, application of ramelteon, a potent melatonin receptor agonist, significantly decreased firing rate and increased inward current within SCN neurons in a GIRK-dependent manner. These results are the first to show that GIRK channels are necessary for the effects of melatonin and ramelteon within the SCN. This study suggests that GIRK channels may be an alternative therapeutic target for diseases with evidence of circadian disruption, including aberrant melatonin signaling. SIGNIFICANCE STATEMENT: Despite the widespread use of melatonin supplementation for the treatment of sleep disruption and other neurological diseases such as epilepsy and depression, no studies have elucidated the molecular mechanisms linking melatonin-induced changes in neuronal activity to its therapeutic effects. Here, we used behavioral and electrophysiological techniques to address this scientific gap. Our results show that melatonin and ramelteon, a potent and clinically relevant melatonin receptor agonist, significantly affect the neurophysiological function of suprachiasmatic nucleus neurons through activation of G-protein-coupled inwardly rectifying potassium (GIRK) channels. Given the importance of GIRK channels for neuronal excitability (with >600 publications on these channels to date), our study should generate broad interest from neuroscientists in fields such as epilepsy, addiction, and cognition.

Anti-CD20 monoclonal antibody therapy in postpartum women with neurological conditions.

OBJECTIVE: Postpartum, patients with multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) have increased risk for disease activity. Anti-CD20 IgG1 monoclonal antibodies (mAb) are increasingly used as disease-modifying therapies (DMTs). Patients may wish to both breastfeed and resume DMT postpartum. This study aimed to determine the transfer of anti-CD20 IgG1 mAbs, ocrelizumab, and rituximab (OCR/RTX), into mature breastmilk and describe maternal and infant outcomes. METHODS: Fifty-seven cis-women receiving OCR/RTX after 59 pregnancies and their infants were enrolled and followed up to 12M postpartum or 90 days post-infusion. Breastmilk was collected pre-infusion and serially up to 90 days and assayed for mAb concentration. Medical records and patients' questionnaire responses were obtained to assess neurologic, breastfeeding, and infant development outcomes. RESULTS: The median average concentration of mAb in breastmilk was low (OCR: 0.08 µg/mL, range 0.05-0.4; RTX: 0.03 µg/mL, range 0.005-0.3). Concentration peaked 1-7 days post-infusion in most (77%) and was nearly undetectable after 90 days. Median average relative infant dose was <1% (OCR: 0.1%, range 0.07-0.7; RTX: 0.04%, range 0.005-0.3). Forty-three participants continued to breastfeed post-infusion. At 8-12 months, the proportion of infants' growth between the 3rd and 97th World Health Organization percentiles did not differ for breastfed (36/40) and non-breastfed (14/16, p > 0.05) infants; neither did the proportion with normal development (breastfed: 37/41, non-breastfed: 11/13; p > 0.05). After postpartum infusion, two mothers experienced a clinical relapse. INTERPRETATION: These confirm minimal transfer of mAb into breastmilk. Anti-CD20 mAb therapy stabilizes MS activity before conception to the postpartum period, and postpartum treatments appears to be safe and well-tolerated for both mother and infant.

A hormonal therapy for menopausal women with MS: A phase Ib/IIa randomized controlled trial.

INTRODUCTION: Most women develop MS before menopause. Menopausal hot flashes can worsen MS symptoms, and could be relieved with hormone therapy. Our objective was to evaluate feasibility, tolerability and symptom response of Duavee® (bazedoxifene + conjugated estrogen) in a Phase Ib/IIa double-blind randomized controlled clinical trial. METHODS: We randomized 24 peri/postmenopausal women with MS and symptomatic hot flashes 1:1 to Duavee® versus placebo. Evaluations occurred at baseline and 2 months. RESULTS: Groups were balanced for age (mean 51.2 ± 3.6 years), EDSS [median 3 (IQR:2.5, 4.5)], and MS duration. 21/24 participants completed the study. FEASIBILITY: Enrollment was protracted (34 months), partially due to concerns about hormone therapy safety. TOLERABILITY: treatment group participants reported greater satisfaction and fewer missed doses; one participant (placebo) developed new MRI lesions; liver function testing remained normal for all patients. SYMPTOMS: Hot Flash Related Daily Interference scale at 2 months was lower in treatment vs. placebo group [median (IQR) of 4 (0.5, 14) vs. 9 (0, 33)]. Between-group differences were not statistically significant. CONCLUSION: Despite perceived benefits in MS, estrogens have perceived risks that represent a hurdle to enrollment. With appropriate education and screening of participants, the favorable study retention (87%) and treatment satisfaction observed in the current study support the feasibility of a longer, powered trial to evaluate whether a proven treatment for menopausal symptoms, Duavee®, could also improve MS-related function in menopausal women with MS.

Circadian rhythm and sleep-wake systems share the dynamic extracellular synaptic milieu.

The mammalian circadian and sleep-wake systems are closely aligned through their coordinated regulation of daily activity patterns. Although they differ in their anatomical organization and physiological processes, they utilize overlapping regulatory mechanisms that include an assortment of proteins and molecules interacting within the extracellular space. These extracellular factors include proteases that interact with soluble proteins, membrane-attached receptors and the extracellular matrix; and cell adhesion molecules that can form complex scaffolds connecting adjacent neurons, astrocytes and their respective intracellular cytoskeletal elements. Astrocytes also participate in the dynamic regulation of both systems through modulating neuronal appositions, the extracellular space and/or through release of gliotransmitters that can further contribute to the extracellular signaling processes. Together, these extracellular elements create a system that integrates rapid neurotransmitter signaling across longer time scales and thereby adjust neuronal signaling to reflect the daily fluctuations fundamental to both systems. Here we review what is known about these extracellular processes, focusing specifically on areas of overlap between the two systems. We also highlight questions that still need to be addressed. Although we know many of the extracellular players, far more research is needed to understand the mechanisms through which they modulate the circadian and sleep-wake systems.

The primary care nurse practitioner and cancer survivorship care.

PURPOSE: To examine the important role that primary care nurse practitioners (NPs) have in providing long-term surveillance and health maintenance for breast, prostate, and colorectal cancer survivors throughout the continuum of cancer care. DATA SOURCES: MEDLINE, CINAHL, MD-Consult, and Cochrane's databases were utilized with the inclusion of primary research and critical research reviews from January 1995 through March 2008. Select organizational websites were also cited. CONCLUSIONS: Cancer patients experience changes in the focus of their care when management shifts from the treatment of cancer to management of treatment side effects and outcomes, to survivorship care, and to secondary cancer treatment. NPs have a strong impact on cancer survivorship care by serving in various roles and settings throughout the cancer trajectory to improve patient outcomes. IMPLICATIONS FOR PRACTICE: Cancer survivorship care expands beyond specialty settings, into primary care. NPs have a key role in ensuring continuity of care for patients with cancer. Models of care that promote continuity and high quality of care for patients with cancer include the shared-care and nurse-managed health center models. The formal collaborative plan of care is essential in long-term cancer survivorship care.

Increasing participant recruitment into large-scale screening trials: experience from the CADET II study.

OBJECTIVES: Multicentre randomized trials frequently encounter difficulties in meeting their recruitment targets, resulting in extension of the trial and delays in implementation of the findings. We report on recruitment strategies implemented in a randomized evaluation of computer-aided detection in women attending routine screening in the UK Breast Screening Programme. SETTING: The target population for the trial was identified from an existing NHS database of women aged 50-70 invited for routine mammography in Coventry, Manchester and Nottingham, UK. Women were asked to consent to their mammograms being randomly allocated (in a ratio of 28:1:1) to one of three film-reading protocols. Trial information was mailed to women, along with the invitation to attend screening, and informed consent was obtained at the mammography appointment. Several strategies were implemented to increase recruitment rates. RESULTS: Recruitment rate increased significantly over time in the study (P < 0.0010 in all centres) with an overall acceptance rate of 46% of those attending screening. Mailing of the trial information sheet separate from the screening invitation in Coventry and Nottingham increased the recruitment rate, even after adjustment for the trend over time and for socioeconomic status of the attendees (P < 0.001). Extension of recruitment to mobile screening units in Nottingham, and the presence of an additional member of staff also improved recruitment (P < 0.001). Simplification of the trial information sheet had little effect. Increases in recruitment rate were not attributable to socioeconomic status of the attendees. CONCLUSIONS: In multicentre trials, monitoring of local recruitment protocols is required to ensure that each centre can maximize accrual targets.

Factors that influence adherence with disease-modifying therapy in MS.

BACKGROUND: The complexity and cost of injection treatment can represent a formidable challenge for patients affected by a chronic illness, particularly those whose treatment is primarily preventative and only modestly effective on the more conspicuous symptomatic aspects of the disease process. The aim of this investigation was to identify which factors most influenced nonadherent behavior with the available disease-modifying injection therapies for multiple sclerosis (MS). METHODS: A multicenter, observational (three-wave) study using surveys was developed and administered to patients with MS through the World Wide Web. Healthcare providers at 17 neurology clinics recruited patients for the study. RESULTS: A total of 798 patients responded to the baseline wave of the study (708 responded to all three waves). The nonadherence rates for all patients (missing one or more injections) across these waves remained relatively stable at 39%, 37%, and 36%, respectively. The most common reason participants listed for missing injections was that they simply forgot to administer the medication (58%). Other factors including injection-site reactions, quality of life, patients' perceptions on the injectable medications, hope, depression, and support were also assessed in relation to adherence. CONCLUSIONS: This study characterizes factors that are associated with failure to fully adhere with disease modifying injection therapy for MS and underscores the principles associated with optimizing adherence and its implications for effective treatment of the disease process in MS.

Response of intrathecal baclofen resistance to dose reduction.

Dose stabilization of intrathecal baclofen (ITB) is usually achieved within 6 to 18 months. In some patients, an increase in ITB dose may result in paradoxical unresponsiveness to baclofen. We present two cases demonstrating increased tone and functional decline with increasing ITB doses after a period of clinical stability. In both cases, reduction of ITB dose was associated with marked clinical improvement.

IM interferon beta-1a delays definite multiple sclerosis 5 years after a first demyelinating event.

BACKGROUND: The Controlled High Risk Subjects Avonex Multiple Sclerosis Prevention Study (CHAMPS) showed that IM interferon beta-1a (IFNbeta-1a) significantly slows the rate of development of clinically definite multiple sclerosis (CDMS) over 2 years in high-risk patients who experience a first clinical demyelinating event. This report highlights the primary results of a 5-year, open-label extension of CHAMPS (the Controlled High Risk Avonex Multiple Sclerosis Prevention Study in Ongoing Neurologic Surveillance [CHAMPIONS Study]). OBJECTIVE: To determine if the benefits of IFNbeta-1a observed in CHAMPS are sustained for up to 5 years. METHODS: CHAMPS patients at participating CHAMPIONS sites were enrolled in the study. All patients were offered, but not required to take, IFNbeta-1a 30 microg IM once weekly for up to 5 years (from CHAMPS randomization). Patients who received placebo in CHAMPS were considered the delayed treatment (DT) group, and patients who received IFNbeta-1a in CHAMPS were considered the immediate treatment (IT) group. The primary outcome measure was the rate of development of CDMS. Additional outcomes included disease state classification at 5 years, annualized relapse rates, disability level at 5 years (Expanded Disability Status Scale), and MRI measures at 5 years. RESULTS: Fifty-three percent (203/383) of patients enrolled in CHAMPIONS (n = 100, IT group; n = 103, DT group) and 64% (32/50) of CHAMPS study sites participated in CHAMPIONS. The median time to initiation of IFNbeta-1a therapy in the DT group was 29 months. The cumulative probability of development of CDMS was significantly lower in the IT group compared with the DT group (5-year incidence 36 +/- 9 vs 49 +/- 10%; p = 0.03). Multivariate analysis suggested that the only factors independently associated with an increased rate of development of CDMS were randomization to the DT group and younger age at onset of neurologic symptoms. Few patients in either group developed major disability within 5 years. CONCLUSIONS: These results support the use of IM interferon beta-1a after a first clinical demyelinating event and indicate that there may be modest beneficial effects of immediate treatment compared with delayed initiation of treatment.

Interferon beta-1a for early multiple sclerosis: CHAMPS trial subgroup analyses.

The objective of this work was to assess the effect of interferon beta-1a (Avonex) on the rate of development of clinically definite multiple sclerosis and brain magnetic resonance imaging changes in subgroups based on type of presenting event, baseline brain magnetic resonance imaging parameters, and demographic factors in the Controlled High-Risk Subjects Avonex Multiple Sclerosis Prevention Study (CHAMPS) trial. After the onset of a first demyelinating event, 383 patients with brain magnetic resonance imaging evidence of subclinical demyelination were treated with corticosteroids and randomly assigned to receive weekly intramuscular injections of 30 microg interferon beta-1a or placebo. The treatment effect within subgroups was assessed in proportional hazards models both for the development of clinically definite multiple sclerosis and for a combined outcome of development of clinically definite multiple sclerosis or >1 new or enlarging T2 lesions on brain magnetic resonance imaging. A beneficial effect of treatment was noted in all subgroups evaluated. Adjusted rate ratios for the development of clinically definite multiple sclerosis in the optic neuritis, brainstem-cerebellar, and spinal cord syndrome subgroups were 0.58 (p = 0.05), 0.40 (p = 0.03), and 0.30 (p = 0.01) and for the development of the combined clinically definite multiple sclerosis/magnetic resonance imaging outcome were 0.50 (p < 0.001), 0.41 (p = 0.001), and 0.40 (p = 0.004), respectively. A treatment benefit on both outcome measures also was seen in subgroups based on baseline brain magnetic resonance imaging parameters, gender, and age. Interferon beta-1a is beneficial when initiated at the first clinical demyelinating event in patients with brain magnetic resonance imaging evidence of subclinical demyelination. The beneficial effect is present for optic neuritis, brainstem-cerebellar syndromes, and spinal cord syndromes.