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Glycoprotein 330/megalin: probable role in receptor-mediated transport of apolipoprotein J alone and in a complex with Alzheimer disease amyloid beta at the blood-brain and blood-cerebrospinal fluid barriers
Zlokovic BV, Martel CL, Matsubara E, McComb JG, Zheng G, McCluskey RT, Frangione B, Ghiso J.. Proceedings of the National Academy of Sciences of the United States of America, 1996-04-01
Topic: Brain proteins, microglia and lab models
Plain-language summary
A soluble form of Alzheimer disease amyloid beta-protein (sA beta) is transported in the blood and cerebrospinal fluid mainly complexed with apolipoprotein J (apoJ). Using a well-characterized in situ perfused guinea pig brain model, we recently obtained preliminary evidence that apoJ facilitates transport of sA beta (1-40)-apoJ complexes across the blood-brain barrier and the blood-cerebrospinal fluid barrier, but the mechanisms remain poorly understood. In the present study, we examined the transport process in greater detail and investigated the possible role of glycoprotein 330 (gp330)/megalin, a receptor for multiple ligands, including apoJ. High-affinity transport systems with a Km of 0.2 and 0.5 nM were demonstrated for apoJ at the blood-brain barrier and the choroid epithelium in vivo, suggesting a specific receptor-mediated mechanism. The sA beta (1-40)-apoJ complex shared the same transport mechanism and exhibited 2.4- to 10.2-fold higher affinity than apoJ itself. Binding to microvessels, transport into brain parenchyma, and choroidal uptake of both apoJ and sA beta (1-40)-apoJ complexes were markedly inhibited (74-99%) in the presence of a monoclonal antibody to gp330/megalin and were virtually abolished by perfusion with the receptor-associated protein, which blocks binding of all known ligands to gp330. Western blot analysis of cerebral microvessels with the monoclonal antibody to gp330 revealed a protein with a mass identical to that in extracts of kidney membranes enriched with gp330/megalin, but in much lower concentration. The findings suggest that gp330/megalin mediates cellular uptake and transport of apoJ and sA beta (1-40)-apoJ complex at the cerebral vascular endothelium and choroid epithelium.
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APA 7th
Zlokovic, B. V., Martel, C. L., Matsubara, E., McComb, J. G., Zheng, G., McCluskey, R. T., et al. (1996). Glycoprotein 330/megalin: probable role in receptor-mediated transport of apolipoprotein J alone and in a complex with Alzheimer disease amyloid beta at the blood-brain and blood-cerebrospinal fluid barriers. Proceedings of the National Academy of Sciences of the United States of America. https://doi.org/10.1073/pnas.93.9.4229
Vancouver
Zlokovic BV, Martel CL, Matsubara E, McComb JG, Zheng G, McCluskey RT, et al. Glycoprotein 330/megalin: probable role in receptor-mediated transport of apolipoprotein J alone and in a complex with Alzheimer disease amyloid beta at the blood-brain and blood-cerebrospinal fluid barriers. Proceedings of the National Academy of Sciences of the United States of America. 1996. doi:10.1073/pnas.93.9.4229. PMID: 8633046.
BibTeX
@article{zlokovic1996-8633046,
author = {Zlokovic, B. V. and Martel, C. L. and Matsubara, E. and McComb, J. G. and Zheng, G. and McCluskey, R. T. and Frangione, B. and Ghiso, J.},
title = {{Glycoprotein 330/megalin: probable role in receptor-mediated transport of apolipoprotein J alone and in a complex with Alzheimer disease amyloid beta at the blood-brain and blood-cerebrospinal fluid barriers}},
journal = {Proceedings of the National Academy of Sciences of the United States of America},
year = {1996},
doi = {10.1073/pnas.93.9.4229},
pmid = {8633046},
url = {https://doi.org/10.1073/pnas.93.9.4229}
}
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. The record names 8 authors; APA and Vancouver show the first six, BibTeX and the downloads carry all of them. Check the citation against the original before you use it.
Key findings
- High-affinity transport systems with a Km of 0.2 and 0.5 nM were demonstrated for apoJ at the blood-brain barrier and the choroid epithelium in vivo, suggesting a specific receptor-mediated mechanism.
- Western blot analysis of cerebral microvessels with the monoclonal antibody to gp330 revealed a protein with a mass identical to that in extracts of kidney membranes enriched with gp330/megalin, but in much lower concentration.
- The findings suggest that gp330/megalin mediates cellular uptake and transport of apoJ and sA beta (1-40)-apoJ complex at the cerebral vascular endothelium and choroid epithelium.
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Study details
- Evidence strengthLow
How this study scored 36/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported, studied in people and randomized / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record, institution's track record and multicenter collaboration, so those were left out: it earned 21 of the 58 points we could judge it on, which is 36 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Proceedings of the National Academy of Sciences of the United States of America) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 1996 — older than 20 years, still counted |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| Randomized / blinded | 0 / 2 | No randomization or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multicenter collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 8633046) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 21 / 58 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 21 of the 58 points we could judge it on is 36 out of 100. |
| Total | 36 / 100 | — |
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