Potential Mechanisms of Progranulin-deficient FTLD

Memory and Aging Center, University of California, San Francisco, 350 Parnassus Avenue, Suite 905, San Francisco, CA 94143, USA.
Journal of Molecular Neuroscience (Impact Factor: 2.34). 09/2011; 45(3):574-82. DOI: 10.1007/s12031-011-9622-3
Source: PubMed


Frontotemporal lobar dementia (FTLD) is the most common cause of dementia in patients younger than 60 years of age, and causes progressive neurodegeneration of the frontal and temporal lobes usually accompanied by devastating changes in language or behavior in affected individuals. Mutations in the progranulin (GRN) gene account for a significant fraction of familial FTLD, and in the vast majority of cases, these mutations lead to reduced expression of progranulin via nonsense-mediated mRNA decay. Progranulin is a secreted glycoprotein that regulates a diverse range of cellular functions including cell proliferation, cell migration, and inflammation. Recent fundamental discoveries about progranulin biology, including the findings that sortilin and tumor necrosis factor receptor (TNFR) are high affinity progranulin receptors, are beginning to shed light on the mechanism(s) by which progranulin deficiency causes FTLD. This review will explore how alterations in basic cellular functions due to PGRN deficiency, both intrinsic and extrinsic to neurons, might lead to the development of FTLD.

Download full-text


Available from: Michael E Ward, May 02, 2015
12 Reads
  • Source
    • "It is also likely that other genes exist that modify the C9ORF72 phenotype. For example, in FTLD-TDP caused by progranulin (GRN) mutations, a number of genes and microRNAs have been identified that alter the disease phenotype [58]. The presence of certain TMEM106B single nucleotide polymorphisms was shown to reduce GRN mutation penetrance possibly by modifying progranulin protein levels [59]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Frontotemporal dementia (FTD) is a common dementia syndrome in patients under the age of 65 years with many features overlapping with amyotrophic lateral sclerosis (ALS). The link between FTD and ALS has been strengthened by the discovery that a hexanucleotide repeat expansion in a non-coding region of the C9ORF72 gene causes both familial and sporadic types of these two diseases. As we begin to understand the pathophysiological mechanisms by which this mutation leads to FTD and ALS (c9FTD/ALS), new targets for disease-modifying therapies will likely be unveiled. Putative C9ORF72 expansion pathogenic mechanisms include loss of C9ORF72 protein function, sequestration of nucleic acid binding proteins due to expanded hexanucleotide repeats, or a combination of the two. New animal models and other research tools informed by work in other repeat expansion neurodegenerative diseases such as the spinocerebellar ataxias will help to elucidate the mechanisms of C9ORF72-mediated disease. Similarly, re-examining previous studies of drugs developed to treat ALS in light of this new mutation may identify novel FTD treatments. Ultimately, research consortiums incorporating animal models and well-characterized clinical populations will be necessary to fully understand the natural history of the c9FTD/ALS clinical phenotypes and identify biomarkers and therapeutic agents that can cure the most common form of genetically determined FTD and ALS.
    Alzheimer's Research and Therapy 11/2012; 4(6):46. DOI:10.1186/alzrt149 · 3.98 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: RNA-binding proteins, and in particular TAR DNA-binding protein 43 (TDP43), are central to the pathogenesis of motor neuron diseases and related neurodegenerative disorders. Studies on human tissue have implicated several possible mechanisms of disease and experimental studies are now attempting to determine whether TDP43-mediated neurodegeneration results from a gain or a loss of function of the protein. In addition, the distinct possibility of pleotropic or combined effects - in which gains of toxic properties and losses of normal TDP43 functions act together - needs to be considered.
    Nature Reviews Neuroscience 11/2011; 13(1):38-50. DOI:10.1038/nrn3121 · 31.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Sortilin and SorLA are members of the Vps10p domain receptor family, the Sortilins, which comprise five type I transmembrane receptors differentially expressed in neuronal tissues of the central and peripheral nervous system. Since the identification of sortilin in 1997, members of this receptor family are recognized as sorting receptors primarily in the trans-Golgi network, interacting with a wide range of ligands comprising other transmembrane receptors as well as soluble proteins from neurotrophic factors to enzymes targeted for lysosomes. Specifically, the involvement of sortilin in neutrophin signaling in healthy and injured neurons is increasingly recognized, as well as the impact of SorLA on the cellular processing of amyloid precursor protein, an important component in Alzheimer's disease. The current understanding of these issues as well as the recent recognition of a molecular link between sortilin and frontotemporal dementia is addressed in this present review.
    Molecular Neurobiology 02/2012; 45(2):379-87. DOI:10.1007/s12035-012-8236-2 · 5.14 Impact Factor
Show more