Survival of adult neurons lacking cholesterol synthesis in vivo

BACKGROUND: Cholesterol, an essential component of all mammalian plasma membranes, is highly enriched in the brain. Both during development and in the adult, brain cholesterol is derived from local cholesterol synthesis and not taken up from the circulation. However, the contribution of neurons and glial cells to total brain cholesterol metabolism is unknown. RESULTS: Using conditional gene inactivation in the mouse, we disrupted the squalene synthase gene (fdft1), which is critical for cholesterol synthesis, in cerebellar granule cells and some precerebellar nuclei. Mutant mice showed no histological signs of neuronal degeneration, displayed ultrastructurally normal synapses, and exhibited normal motor coordination. This revealed that these adult neurons do not require cell-autonomous cholesterol synthesis for survival or function. CONCLUSION: We conclude that at least some adult neurons no longer require endogenous cholesterol synthesis and can fully meet their cholesterol needs by uptake from their surrounding. Glia are a likely source of cholesterol in the central nervous system

Regulatory T cells promote myelin regeneration in the central nervous system

Regeneration of CNS myelin involves differentiation of oligodendrocytes from oligodendrocyte progenitor cells. In multiple sclerosis, remyelination can fail despite abundant oligodendrocyte progenitor cells, suggesting impairment of oligodendrocyte differentiation. T cells infiltrate the CNS in multiple sclerosis, yet little is known about T cell functions in remyelination. We report that regulatory T cells (T$_{reg}$) promote oligodendrocyte differentiation and (re)myelination. T$_{reg}$-deficient mice exhibited substantially impaired remyelination and oligodendrocyte differentiation, which was rescued by adoptive transfer of T$_{reg}$. In brain slice cultures, T$_{reg}$ accelerated developmental myelination and remyelination, even in the absence of overt inflammation. T$_{reg}$ directly promoted oligodendrocyte progenitor cell differentiation and myelination in vitro. We identified CCN3 as a T$_{reg}$-derived mediator of oligodendrocyte differentiation and myelination in vitro. These findings reveal a new regenerative function of T$_{reg}$ in the CNS, distinct from immunomodulation. Although the cells were originally named 'T$_{reg}$' to reflect immunoregulatory roles, this also captures emerging, regenerative T$_{reg}$ functions.This work was supported by the Biotechnology and Biological Sciences Research Council (BB/J01026X/1 and BB/N003721/1, to D.C.F.), The Leverhulme Trust (ECF-2014-390, to Y.D.), QUB (QUB - Lucy McGuigan Bequest, to D.C.F.), The UK Multiple Sclerosis Society (941 and 50, to R.J.M.F. and C.Z.), MRC UK Regenerative Medicine platform (MR/KO26666/1, to A.C.W.), University of Edinburgh Wellcome Trust Multi User Equipment Grant (WT104915MA, to A.C.W.), by a core support grant from the Wellcome Trust and MRC to the Wellcome Trust - Medical Research Council Cambridge Stem Cell Institute (097922/Z/11/Z to R.J.M.F.), studentship support from Dept. for the Economy (Northern Ireland) and British Pathological Society, US National Multiple Sclerosis Society (RG5203A4, to J.R.C.), NIH/NINDS (NS095889, to J.R.C.), NIH/NIGMS IRACDA Postdoctoral Fellowship (K12GM081266, to S.R.M.) and Wellcome Trust (110138/Z/15/Z, to D.C.F.)

Familial t(1;11) translocation is associated with disruption of white matter structural integrity and oligodendrocyte–myelin dysfunction

Although the underlying neurobiology of major mental illness (MMI) remains unknown, emerging evidence implicates a role for oligodendrocyte–myelin abnormalities. Here, we took advantage of a large family carrying a balanced t(1;11) translocation, which substantially increases risk of MMI, to undertake both diffusion tensor imaging and cellular studies to evaluate the consequences of the t(1;11) translocation on white matter structural integrity and oligodendrocyte–myelin biology. This translocation disrupts among others the DISC1 gene which plays a crucial role in brain development. We show that translocation-carrying patients display significant disruption of white matter integrity compared with familial controls. At a cellular level, we observe dysregulation of key pathways controlling oligodendrocyte development and morphogenesis in induced pluripotent stem cell (iPSC) derived case oligodendrocytes. This is associated with reduced proliferation and a stunted morphology in vitro. Further, myelin internodes in a humanized mouse model that recapitulates the human translocation as well as after transplantation of t(1;11) oligodendrocyte progenitors were significantly reduced when compared with controls. Thus we provide evidence that the t(1;11) translocation has biological effects at both the systems and cellular level that together suggest oligodendrocyte–myelin dysfunction

Category fluency is also predominantly affected in Swiss Alzheimer's disease patients

OBJECTIVES: To establish the comparative efficacy to differentiate between Swiss patients with dementia of the Alzheimer type (DAT) and elderly normal control subjects (NC) on two different verbal fluency tasks: category fluency and letter fluency. MATERIAL AND METHODS: Fifty Swiss German DAT patients in the early stages of the disease and 50 matched normal control subjects were compared on letter and category fluency tasks. RESULTS: DAT patients exhibited an overproportional impairment on category fluency as compared with letter fluency. Receiver operating characteristic curves (ROC) showed that category fluency correctly classified a significantly higher number of DAT patients and NC subjects (84%) than letter fluency (70%). CONCLUSION: As similar findings have been described for English-speaking DAT patients, we conclude that deficiencies in category fluency are a general phenomenon, reflecting impaired structures of semantic knowledge occurring early in the course of Alzheimer's disease

Memory Clinics in Switzerland. Collaborative Group of Swiss Memory Clinics

Currently, eleven Memory Clinics (MC) in Switzerland offer their services to patients, caregivers and family doctors. Their primary goal is the early diagnosis and management of dementia in elderly outpatients. Special emphasis is put on the detection of reversible causes of dementing disorders. Diagnoses and medical, pharmacological, neuropsychological and social treatment recommendations are established in a multidisciplinary consensus conference and communicated back to the referring physicians. The psychosocial therapies and supportive activities include counseling, memory training for patients, neuropsychological rehabilitation, caregiver groups, relaxation and biofeedback training, day care centers, Alzheimer's Tanzcafé, and special vacations for dementia patients. These activities vary from MC to MC according to the availability of resources. Research activities are an integral part of all MCs and range from the attempt to identify preclinical markers of Alzheimer's disease to studies of neuropathological correlates of cognitive disturbances. Moreover, patients are encouraged to participate in studies investigating new medications. MCs play an important role in the education and training of health care professionals and in raising awareness and support in the general population. What do you want to do ? New mail Cop

Early detection of Alzheimer's disease with a total score of the German CERAD

The goal of the present study was to evaluate the diagnostic discriminability of three different global scores for the German version of the Consortium to Establish a Registry on Alzheimer's Disease-Neuropsychological Assessment Battery (CERAD-NAB). The CERAD-NAB was administered to 1100 healthy control participants [NC; Mini-Mental State Examination (MMSE) mean = 28.9] and 352 patients with very mild Alzheimer's disease (AD; MMSE mean = 26.1) at baseline and subsets of participants at follow-up an average of 2.4 (NC) and 1.2 (AD) years later. We calculated the following global scores: Chandler et al.'s (2005) score (summed raw scores), logistic regression on principal components analysis scores (PCA-LR), and logistic regression on demographically corrected CERAD-NAB variables (LR). Correct classification rates (CCR) were compared with areas under the receiver operating characteristics curves (AUC). The CCR of the LR score (AUC = .976) exceeded that of the PCA-LR, while the PCA-LR (AUC = .968) and Chandler (AUC = .968) scores performed comparably. Retest data improved the CCR of the PCA-LR and Chandler (trend) scores. Thus, for the German CERAD-NAB, Chandler et al.'s total score provided an effective global measure of cognitive functioning, whereby the inclusion of retest data tended to improve correct classification of individual cases