Journal
ACTA NEUROPATHOLOGICA COMMUNICATIONS
Volume 7, Issue 1, Pages -Publisher
BMC
DOI: 10.1186/s40478-019-0862-8
Keywords
Amyloid; Aggregation; Growth factors; Alzheimer's disease; Progranulin; Prosaposin; Neuropathology; Tangles; Interactions
Categories
Funding
- Japan Society for the Promotion of Science [JP17H03560]
- National Institute of Neurological Disorders and Stroke [U24 NS072026]
- National Institute on Aging [P30 AG19610]
- Arizona Department of Health Services [211002]
- Arizona Biomedical Research Commission [4001, 0011, 05-901, 1001]
- Michael J. Fox Foundation for Parkinson's Research (The Prescott Family Initiative)
Ask authors/readers for more resources
Progranulin (PGRN) is a protein encoded by the GRN gene with multiple identified functions including as a neurotrophic factor, tumorigenic growth factor, anti-inflammatory cytokine and regulator of lysosomal function. A single mutation in the human GRN gene resulting in reduced PGRN expression causes types of frontotemporal lobar degeneration resulting in frontotemporal dementia. Prosaposin (PSAP) is also a multifunctional neuroprotective secreted protein and regulator of lysosomal function. Interactions of PGRN and PSAP affect their functional properties. Their roles in Alzheimer's disease (AD), the leading cause of dementia, have not been defined. In this report, we examined in detail the cellular expression of PGRN in middle temporal gyrus samples of a series of human brain cases (n = 45) staged for increasing plaque pathology. Immunohistochemistry showed PGRN expression in cortical neurons, microglia, cerebral vessels and amyloid beta (A beta) plaques, while PSAP expression was mainly detected in neurons and A beta plaques, and to a limited extent in astrocytes. We showed that there were increased levels of PGRN protein in AD cases and corresponding increased levels of PSAP. Levels of PGRN and PSAP protein positively correlated with amyloid beta (A beta), with PGRN levels correlating with phosphorylated tau (serine 205) levels in these samples. Although PGRN colocalized with lysosomal-associated membrane protein-1 in neurons, most PGRN associated with A beta plaques did not. A beta plaques with PGRN and PSAP deposits were identified in the low plaque non-demented cases suggesting this was an early event in plaque formation. We did not observe PGRN-positive neurofibrillary tangles. Co-immunoprecipitation studies of PGRN from brain samples identified only PSAP associated with PGRN, not sortilin or other known PGRN-binding proteins, under conditions used. Most PGRN associated with A beta plaques were immunoreactive for PSAP showing a high degree of colocalization of these proteins that did not change between disease groups. As PGRN supplementation has been considered as a therapeutic approach for AD, the possible involvement of PGRN and PSAP interactions in AD pathology needs to be further considered.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available