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Gamma subunit of complement component 8 is a neuroinflammation inhibitor
Jong-Heon Kim, Ruqayya Afridi, Jin Han, Hyun-Gug Jung, Seung-Chan Kim, Eun Mi Hwang, Hyun Soo Shim, Hoon Ryu et al.. Brain : a journal of neurology, 2021-03-03
Topic: Inflammation, microglia and astrocytes
The complement system is part of the innate immune system that comprises several small proteins activated by sequential cleavages. The majority of these complement components, such as components 3a (C3a) and C5a, are chemotactic and pro-inflammatory. However, in this study, we revealed an inhibitory role of complement component 8 gamma (C8G) in neuroinflammation. In patients with Alzheimer's disease, who exhibit strong neuroinflammation, we found higher C8G levels in brain tissue, CSF, and plasma. Our novel findings also showed that the expression level of C8G increases in the inflamed mouse brain, and that C8G is mainly localized to brain astrocytes. Experiments using recombinant C8G protein and shRNA-mediated knockdown showed that C8G inhibits glial hyperactivation, neuroinflammation, and cognitive decline in acute and chronic animal models of Alzheimer's disease. Additionally, we identified sphingosine-1-phosphate receptor 2 (S1PR2) as a novel interaction protein of C8G and demonstrated that astrocyte-derived C8G interacts with S1PR2 to antagonize the pro-inflammatory action of S1P in microglia. Taken together, our results reveal the previously unrecognized role of C8G as a neuroinflammation inhibitor. Our findings pave the way towards therapeutic containment of neuroinflammation in Alzheimer's disease and related neurological diseases.
Key findings
- However, in this study, we revealed an inhibitory role of complement component 8 gamma (C8G) in neuroinflammation.
- In patients with Alzheimer's disease, who exhibit strong neuroinflammation, we found higher C8G levels in brain tissue, CSF, and plasma.
- Our novel findings also showed that the expression level of C8G increases in the inflamed mouse brain, and that C8G is mainly localized to brain astrocytes.
- Experiments using recombinant C8G protein and shRNA-mediated knockdown showed that C8G inhibits glial hyperactivation, neuroinflammation, and cognitive decline in acute and chronic animal models of Alzheimer's disease.
- Additionally, we identified sphingosine-1-phosphate receptor 2 (S1PR2) as a novel interaction protein of C8G and demonstrated that astrocyte-derived C8G interacts with S1PR2 to antagonize the pro-inflammatory action of S1P in microglia.
Study details
- Evidence strengthLow
How this study scored 45/100
Published in a leading specialty journal. Scored zero for study design, sample size, effect reported, studied in people and randomised / 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, multi-centre collaboration and free to read, so those were left out: it earned 25 of the 56 points we could judge it on, which is 45 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Brain : a journal of neurology) |
| 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 | 3 / 5 | 2021 — within 6 year(s) of the newest study here |
| 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) |
| Randomised / blinded | 0 / 2 | No randomisation 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 |
| Multi-centre collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 33382892) |
| Free to read | — / 2 | Access not recorded — left out of this score |
| Points | 25 / 56 | Scored on 10 of 20 parts. We have no data for the rest, so they are left out: 25 of the 56 points we could judge it on is 45 out of 100. |
| Total | 45 / 100 | — |
What each of these 20 components measures, and what this score is not →
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Cite this study APA, Vancouver, BibTeX · download .bib or .ris
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's author list ends in “et al.”, so not every author is named. Check the citation against the original before you use it.
APA 7th
Kim, J.-H., Afridi, R., Han, J., Jung, H.-G., Kim, S.-C., Hwang, E. M., et al. (2021). Gamma subunit of complement component 8 is a neuroinflammation inhibitor. Brain : a journal of neurology. https://doi.org/10.1093/brain/awaa425
Vancouver
Kim J.-H, Afridi R, Han J, Jung H.-G, Kim S.-C, Hwang EM, et al. Gamma subunit of complement component 8 is a neuroinflammation inhibitor. Brain : a journal of neurology. 2021. doi:10.1093/brain/awaa425. PMID: 33382892.
BibTeX
@article{kim2021-33382892,
author = {Kim, Jong-Heon and Afridi, Ruqayya and Han, Jin and Jung, Hyun-Gug and Kim, Seung-Chan and Hwang, Eun Mi and Shim, Hyun Soo and Ryu, Hoon and others},
title = {{Gamma subunit of complement component 8 is a neuroinflammation inhibitor}},
journal = {Brain : a journal of neurology},
year = {2021},
doi = {10.1093/brain/awaa425},
pmid = {33382892},
url = {https://doi.org/10.1093/brain/awaa425}
}
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