5 research outputs found
Complement C5aR1 signaling promotes polarization and proliferation of embryonic neural progenitor cells through PKCζ
The complement system, typically associated with innate immunity, is emerging as a key controller of nonimmune systems including in development, with recent studies linking complement mutations with neurodevelopmental disease. A key effector of the complement response is the activation fragment C5a, which, through its receptor C5aR1, is a potent driver of inflammation. Surprisingly, C5aR1 is also expressed during early mammalian embryogenesis; however, no clearly defined function is ascribed to C5aR1 in development. Here we demonstrate polarized expression of C5aR1 on the apical surface of mouse embryonic neural progenitor cells in vivo and on human embryonic stem cell-derived neural progenitors. We also show that signaling of endogenous C5a during mouse embryogenesis drives proliferation of neural progenitor cells within the ventricular zone and is required for normal brain histogenesis. C5aR1 signaling in neural progenitors was dependent on atypical protein kinase C ζ, a mediator of stem cell polarity, with C5aR1 inhibition reducing proliferation and symmetric division of apical neural progenitors in human and mouse models. C5aR1 signaling was shown to promote the maintenance of cell polarity, with exogenous C5a increasing the retention of polarized rosette architecture in human neural progenitors after physical or chemical disruption. Transient inhibition of C5aR1 during neurogenesis in developing mice led to behavioral abnormalities in both sexes and MRI-detected brain microstructural alterations, in studied males, demonstrating a requirement of C5aR1 signaling for appropriate brain development. This study thus identifies a functional role for C5a–C5aR1 signaling in mammalian neurogenesis and provides mechanistic insight into recently identified complement gene mutations and brain disorders
Proteomics of Huntington's disease-affected human embryonic stem cells reveals an evolving pathology involving mitochondrial dysfunction and metabolic disturbances
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a mutation in the Huntingtin gene, where excessive (≥36) CAG repeats encode for glutamine expansion in the huntingtin protein. Research using mouse models and human pathological material has indicated dysfunctions in a myriad of systems, including mitochondrial and ubiquitin/proteasome complexes, cytoskeletal transport, signaling, and transcriptional regulation. Here, we examined the earliest biochemical and pathways involved in HD pathology. We conducted a proteomics study combined with immunocytochemical analysis of undifferentiated HD-affected and unaffected human embryonic stem cells (hESC). Analysis of 1883 identifications derived from membrane and cytosolic enriched fractions revealed mitochondria as the primary dysfunctional organ in HD-affected pluripotent cells in the absence of significant differences in huntingtin protein. Furthermore, on the basis of analysis of 645 proteins found in neurodifferentiated hESC, we show a shift to transcriptional dysregulation and cytoskeletal abnormalities as the primary pathologies in HD-affected cells differentiating along neural lineages in vitro. We also show this is concomitant with an up-regulation in expression of huntingtin protein in HD-affected cells. This study demonstrates the utility of a model that recapitulates HD pathology and offers insights into disease initiation, etiology, progression, and potential therapeutic intervention.12 page(s
Proteomics of Huntington’s Disease-Affected Human Embryonic Stem Cells Reveals an Evolving Pathology Involving Mitochondrial Dysfunction and Metabolic Disturbances
Huntington’s
disease (HD) is an autosomal dominant neurodegenerative
disorder caused by a mutation in the Huntingtin gene, where excessive
(≥36) CAG repeats encode for glutamine expansion in the huntingtin
protein. Research using mouse models and human pathological material
has indicated dysfunctions in a myriad of systems, including mitochondrial
and ubiquitin/proteasome complexes, cytoskeletal transport, signaling,
and transcriptional regulation. Here, we examined the earliest biochemical
and pathways involved in HD pathology. We conducted a proteomics study
combined with immunocytochemical analysis of undifferentiated HD-affected
and unaffected human embryonic stem cells (hESC). Analysis of 1883
identifications derived from membrane and cytosolic enriched fractions
revealed mitochondria as the primary dysfunctional organ in HD-affected
pluripotent cells in the absence of significant differences in huntingtin
protein. Furthermore, on the basis of analysis of 645 proteins found
in neurodifferentiated hESC, we show a shift to transcriptional dysregulation
and cytoskeletal abnormalities as the primary pathologies in HD-affected
cells differentiating along neural lineages in vitro. We also show
this is concomitant with an up-regulation in expression of huntingtin
protein in HD-affected cells. This study demonstrates the utility
of a model that recapitulates HD pathology and offers insights into
disease initiation, etiology, progression, and potential therapeutic
intervention