Excess α-synuclein compromises phagocytosis in iPSC-derived macrophages

To examine the pathogenic role of α-synuclein (αS) in Parkinson's Disease, we have generated induced Pluripotent Stem Cell lines from early onset Parkinson's Disease patients with SNCA A53T and SNCA Triplication mutations, and in this study have differentiated them to PSC-macrophages (pMac), which recapitulate many features of their brain-resident cousins, microglia. We show that SNCA Triplication pMac, but not A53T pMac, have significantly increased intracellular αS versus controls and release significantly more αS to the medium. SNCA Triplication pMac, but not A53T pMac, show significantly reduced phagocytosis capability and this can be phenocopied by adding monomeric αS to the cell culture medium of control pMac. Fibrillar αS is taken up by pMac by actin-rearrangement-dependent pathways, and monomeric αS by actin-independent pathways. Finally, pMac degrade αS and this can be arrested by blocking lysosomal and proteasomal pathways. Together, these results show that macrophages are capable of clearing αS, but that high levels of exogenous or endogenous αS compromise this ability, likely a vicious cycle scenario faced by microglia in Parkinson's disease

A highly efficient human pluripotent stem cell microglia model displays a neuronal-co-culture-specific expression profile and inflammatory response

Microglia are increasingly implicated in brain pathology, particularly neurodegenerative disease, with many genes implicated in Alzheimer's, Parkinson's, and motor neuron disease expressed in microglia. There is, therefore, a need for authentic, efficient in vitro models to study human microglial pathological mechanisms. Microglia originate from the yolk sac as MYB-independent macrophages, migrating into the developing brain to complete differentiation. Here, we recapitulate microglial ontogeny by highly efficient differentiation of embryonic MYB-independent iPSC-derived macrophages then co-culture them with iPSC-derived cortical neurons. Co-cultures retain neuronal maturity and functionality for many weeks. Co-culture microglia express key microglia-specific markers and neurodegenerative disease-relevant genes, develop highly dynamic ramifications, and are phagocytic. Upon activation they become more ameboid, releasing multiple microglia-relevant cytokines. Importantly, co-culture microglia downregulate pathogen-response pathways, upregulate homeostatic function pathways, and promote a more anti-inflammatory and pro-remodeling cytokine response than corresponding monocultures, demonstrating that co-cultures are preferable for modeling authentic microglial physiology

Natural history specimens collected and/or identified and deposited.

Natural history specimen data collected and/or identified by Felix Haenseler, http://www.wikidata.org/entity/Q5858554. Claims or attributions were made on Bionomia, https://bionomia.net using specimen data from the Global Biodiversity Information Facility, https://gbif.org.http://www.wikidata.org/entity/Q585855

Concise Review: Modeling Neurodegenerative Diseases with Human Pluripotent Stem Cell-Derived Microglia

Inflammation of the brain and the consequential immunological responses play pivotal roles in neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and frontotemporal dementia (FTD). Microglia, the resident macrophage cells of the brain, have also emerged as key players in neuroinflammation. As primary human microglia from living subjects are normally not accessible to researchers, there is a pressing need for an alternative source of authentic human microglia which allows modeling of neurodegeneration in vitro. Several protocols for induced pluripotent stem cell (iPSC)‐derived microglia have recently been developed and provide unlimited access to patient‐derived material. In this present study, we give an overview of iPSC‐derived microglia models in mono‐culture and coculture systems, their advantages and limitations, and how they have already been used for disease phenotyping. Furthermore, we outline some of the gene engineering tools to generate isogenic controls, the creation of gene knockout iPSC lines as well as covering reporter cell lines which could help to elucidate complex cell interaction mechanisms in the microglia/neuron coculture system, for example, microglia‐induced synapse loss. Finally, we deliberate on how said cocultures could aid in personalized drug screening to identify patient‐specific therapies against neurodegeneration

Ensayo para una analisis de las aguas de Carratraca

Descripcion del criadero de nikel de Carratraca / por Antonio Alvarez de Linera.Archidona.Reseña historica del santuario de Nuestra Señora de los Remedios, patrona excelsa de la ciudad de Velez-Malaga / J. M. Villasclaras Rojas.Una pagina de critica historica / J. M. Villasclaras Rojas.Proceso de Tolox.Reseña historica de la villa de Nerja / por Alejandro Bueno Garcia.Copia digital : Diputación de Málaga. Biblioteca Canovas del Castillo, 201

Benzidine stain for the histochemical detection of hemoglobin in splinter hemorrhage (subungual hematoma) and black heel

Minor nail trauma may cause bluish discoloration of the nail, while tangential skin trauma on the heel can result in a so-called black heel. To rule out melanoma in such clinical situations, a biopsy is needed to reveal homogeneous eosinophilic masses deposited under the nail plate or within it (transepidermal elimination). Most dermatopathologists attempt to demonstrate the presence of hemoglobin in these eosinophilic masses with Prussian blue stain, which typically remains negative. In our experience, these traumatically induced blood deposits are always situated in avascular spaces, devoid of degrading phagocytes. Consequently, a histochemical stain for these deposits should be directed specifically toward hemoglobin, not hemosiderin. In the dermatopathologic literature, the various techniques to detect hemoglobin deposits in tissue sections are not well-known. We would like to emphasize benzidine stain, a highly selective and efficient method to demonstrate the presence of hemoglobin deposits in histologic sections. To date, benzidine stain has not been utilized to characterize splinter hemorrhage (subungual hematoma). Of concern, the use of benzidine in histopathology laboratories is restricted because this agent is a known carcinogen, while the non-mutagenic derivative, 3,3',5,5'-tetramethylbenzidine, does not stain histologic sections. Patent blue V, a completely different and less specific agent, stains hemoglobin an intense blue-green