A Novel T Cell Receptor Transgenic Animal Model of Seborrheic Dermatitis-Like Skin Disease

We have characterized a novel animal model of the common inflammatory skin disease seborrheic dermatitis (SD) that involves the expression of the self-specific 2C transgenic T cell receptor on the DBA/2 genetic background. Opportunistic fungal pathogens are present in the primary histological lesions and severe disease can be mitigated by the administration of fluconazole, demonstrating a role for infection in disease pathogenesis. Spontaneous disease convalescence occurs at 70–90 d of age and is preceded by an expansion of CD4+ T cells that partially restores the T cell lymphopenia that occurs in these animals. The adoptive transfer of syngeneic CD4+ T cells into pre-diseased DBA/2 2C mice completely abrogates the development of cutaneous disease. The pattern of disease inheritance in DBA/2 backcrosses suggests that one, or a closely linked group of genes, may control disease penetrance. Bone marrow reconstitution experiments demonstrated that the DBA/2 susceptibility factor(s) governing disease penetrance is likely non-hematopoietic since bone marrow from disease-resistant 2C mice can adoptively transfer the full disease phenotype to non-transgenic DBA/2 animals. This model implicates fungal organisms and CD4+ T cell lymphopenia in the development of a SD-like condition and, as such, may mimic the development of SD in acquired immunodeficiency syndrome

Lack of Neuronal IFN-β-IFNAR Causes Lewy Body- and Parkinson's Disease-like Dementia.

Neurodegenerative diseases have been linked to inflammation, but whether altered immunomodulation plays a causative role in neurodegeneration is not clear. We show that lack of cytokine interferon-β (IFN-β) signaling causes spontaneous neurodegeneration in the absence of neurodegenerative disease-causing mutant proteins. Mice lacking Ifnb function exhibited motor and cognitive learning impairments with accompanying α-synuclein-containing Lewy bodies in the brain, as well as a reduction in dopaminergic neurons and defective dopamine signaling in the nigrostriatal region. Lack of IFN-β signaling caused defects in neuronal autophagy prior to α-synucleinopathy, which was associated with accumulation of senescent mitochondria. Recombinant IFN-β promoted neurite growth and branching, autophagy flux, and α-synuclein degradation in neurons. In addition, lentiviral IFN-β overexpression prevented dopaminergic neuron loss in a familial Parkinson's disease model. These results indicate a protective role for IFN-β in neuronal homeostasis and validate Ifnb mutant mice as a model for sporadic Lewy body and Parkinson's disease dementia.Support to S.I.-N. was from Danish Council For Independent Research (DFF)-Medical Sciences, Alzheimer-forskningsfonden, Danish Multiple Sclerosis Society, Danish Cancer Society and Lundbeck Foundation. D.C.R. is a Wellcome Trust Principal Research Fellow.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.cell.2015.08.06

Microglial inclusions and neurofilament light chain release follow neuronal α-synuclein lesions in long-term brain slice cultures.

BACKGROUND: Proteopathic brain lesions are a hallmark of many age-related neurodegenerative diseases including synucleinopathies and develop at least a decade before the onset of clinical symptoms. Thus, understanding of the initiation and propagation of such lesions is key for developing therapeutics to delay or halt disease progression. METHODS: Alpha-synuclein (αS) inclusions were induced in long-term murine and human slice cultures by seeded aggregation. An αS seed-recognizing human antibody was tested for blocking seeding and/or spreading of the αS lesions. Release of neurofilament light chain (NfL) into the culture medium was assessed. RESULTS: To study initial stages of α-synucleinopathies, we induced αS inclusions in murine hippocampal slice cultures by seeded aggregation. Induction of αS inclusions in neurons was apparent as early as 1week post-seeding, followed by the occurrence of microglial inclusions in vicinity of the neuronal lesions at 2-3 weeks. The amount of αS inclusions was dependent on the type of αS seed and on the culture's genetic background (wildtype vs A53T-αS genotype). Formation of αS inclusions could be monitored by neurofilament light chain protein release into the culture medium, a fluid biomarker of neurodegeneration commonly used in clinical settings. Local microinjection of αS seeds resulted in spreading of αS inclusions to neuronally connected hippocampal subregions, and seeding and spreading could be inhibited by an αS seed-recognizing human antibody. We then applied parameters of the murine cultures to surgical resection-derived adult human long-term neocortical slice cultures from 22 to 61-year-old donors. Similarly, in these human slice cultures, proof-of-principle induction of αS lesions was achieved at 1week post-seeding in combination with viral A53T-αS expressions. CONCLUSION: The successful translation of these brain cultures from mouse to human with the first reported induction of human αS lesions in a true adult human brain environment underlines the potential of this model to study proteopathic lesions in intact mouse and now even aged human brain environments

IFNB1/interferon-ß-induced autophagy in MCF-7 breast cancer cells counteracts its proapoptotic function

IFNB1/interferon (IFN)-β belongs to the type I IFNs and exerts potent antiproliferative, proapoptotic, antiangiogenic and immunemodulatory functions. Despite the beneficial effects of IFNB1 in experimental breast cancers, clinical translation has been disappointing, possibly due to induction of survival pathways leading to treatment resistance. Defects in autophagy, a conserved cellular degradation pathway, are implicated in numerous cancer diseases. Autophagy is induced in response to cancer therapies and can contribute to treatment resistance. While the type II IFN, IFNG, which in many aspects differs significantly from type I IFNs, can induce autophagy, no such function for any type I IFN has been reported. We show here that IFNB1 induces autophagy in MCF-7, MDAMB231 and SKBR3 breast cancer cells by measuring the turnover of two autophagic markers, MAP1LC3B/LC3 and SQSTM1/p62. The induction of autophagy in MCF-7 cells occurred upstream of the negative regulator of autophagy MTORC1, and autophagosome formation was dependent on the known core autophagy molecule ATG7 and the IFNB1 signaling molecule STAT1. Using siRNA-mediated silencing of several core autophagy molecules and STAT1, we provide evidence that IFNB1 mediates its antiproliferative effects independent of autophagy, while the proapoptotic function of IFNB1 was strongly enhanced in the absence of autophagy. This suggests that autophagy induced by IFNB1 promoted survival, which might contribute to tumor resistance against IFNB1 treatment. It may therefore be clinically relevant to reconcile a role for IFNB1 in the treatment of breast cancer with concomitant inhibition of autophagy

PD-L1 expression by neurons nearby tumors indicates better prognosis in glioblastoma patients

Glioblastoma multiforme (GBM) is the most aggressive form of brain tumor. In general, tumor growth requires disruption of the tissue microenvironment, yet how this affects glioma progression is unknown. We studied program death-ligand (PD-L)1 in neurons and gliomas in tumors from GBM patients and associated the findings with clinical outcome. Remarkably, we found that upregulation of PD-L1 by neurons in tumor-adjacent brain tissue (TABT) associated positively with GBM patient survival, whereas lack of neuronal PD-L1 expression was associated with high PD-L1 in tumors and unfavorable prognosis. To understand the molecular mechanism of PD-L1 signaling in neurons, we investigated PD-L1 function in cerebellar and cortical neurons and its impact on gliomas. We discovered that neuronal PD-L1-induced caspase-dependent apoptosis of glioma cells. Because interferon (IFN)-β induces PD-L1 expression, we studied the functional consequences of neuronal Ifnb gene deletion on PD-L1 signaling and function. Ifnb(-/-) neurons lacked PD-L1 and were defective in inducing glioma cell death; this effect was reversed on PD-L1 gene transfection. Ifnb(-/-) mice with intracerebral isografts survived poorly. Similar to the observations in GBM patients, better survival in wild-type mice was associated with high neuronal PD-L1 in TABT and downregulation of PD-L1 in tumors, which was defective in Ifnb(-/-) mice. Our data indicated that neuronal PD-L1 signaling in brain cells was important for GBM patient survival. Reciprocal PD-L1 regulation in TABT and tumor tissue could be a prognostic biomarker for GBM. Understanding the complex interactions between tumor and adjacent stromal tissue is important in designing targeted GBM therapies

A Loss-of-Function Screen for Phosphatases that Regulate Neurite Outgrowth Identifies PTPN12 as a Negative Regulator of TrkB Tyrosine Phosphorylation

<div><p>Alterations in function of the neurotrophin BDNF are associated with neurodegeneration, cognitive decline, and psychiatric disorders. BDNF promotes axonal outgrowth and branching, regulates dendritic tree morphology and is important for axonal regeneration after injury, responses that largely result from activation of its tyrosine kinase receptor TrkB. Although intracellular neurotrophin (NT) signaling presumably reflects the combined action of kinases and phosphatases, little is known about the contributions of the latter to TrkB regulation. The issue is complicated by the fact that phosphatases belong to multiple independently evolved families, which are rarely studied together. We undertook a loss-of-function RNA-interference-based screen of virtually all known (254) human phosphatases to understand their function in BDNF/TrkB-mediated neurite outgrowth in differentiated SH-SY5Y cells. This approach identified phosphatases from diverse families, which either positively or negatively modulate BDNF-TrkB-mediated neurite outgrowth, and most of which have little or no previously established function related to NT signaling. “Classical” protein tyrosine phosphatases (PTPs) accounted for 13% of the candidate regulatory phosphatases. The top classical PTP identified as a negative regulator of BDNF-TrkB-mediated neurite outgrowth was PTPN12 (also called PTP-PEST). Validation and follow-up studies showed that endogenous PTPN12 antagonizes tyrosine phosphorylation of TrkB itself, and the downstream activation of ERK1/2. We also found PTPN12 to negatively regulate phosphorylation of p130cas and FAK, proteins with previously described functions related to cell motility and growth cone behavior. Our data provide the first comprehensive survey of phosphatase function in NT signaling and neurite outgrowth. They reveal the complexity of phosphatase control, with several evolutionarily unrelated phosphatase families cooperating to affect this biological response, and hence the relevance of considering all phosphatase families when mining for potentially druggable targets.</p></div