| First Author | Li Q | Year | 2024 |
| Journal | J Neuroinflammation | Volume | 21 |
| Issue | 1 | Pages | 125 |
| PubMed ID | 38730470 | Mgi Jnum | J:348388 |
| Mgi Id | MGI:7640816 | Doi | 10.1186/s12974-024-03119-2 |
| Citation | Li Q, et al. (2024) Monocytes release cystatin F dimer to associate with Abeta and aggravate amyloid pathology and cognitive deficits in Alzheimer's disease. J Neuroinflammation 21(1):125 |
| abstractText | BACKGROUND: Understanding the molecular mechanisms of Alzheimer's disease (AD) has important clinical implications for guiding therapy. Impaired amyloid beta (Abeta) clearance is critical in the pathogenesis of sporadic AD, and blood monocytes play an important role in Abeta clearance in the periphery. However, the mechanism underlying the defective phagocytosis of Abeta by monocytes in AD remains unclear. METHODS: Initially, we collected whole blood samples from sporadic AD patients and isolated the monocytes for RNA sequencing analysis. By establishing APP/PS1 transgenic model mice with monocyte-specific cystatin F overexpression, we assessed the influence of monocyte-derived cystatin F on AD development. We further used a nondenaturing gel to identify the structure of the secreted cystatin F in plasma. Flow cytometry, enzyme-linked immunosorbent assays and laser scanning confocal microscopy were used to analyse the internalization of Abeta by monocytes. Pull down assays, bimolecular fluorescence complementation assays and total internal reflection fluorescence microscopy were used to determine the interactions and potential interactional amino acids between the cystatin F protein and Abeta. Finally, the cystatin F protein was purified and injected via the tail vein into 5XFAD mice to assess AD pathology. RESULTS: Our results demonstrated that the expression of the cystatin F protein was specifically increased in the monocytes of AD patients. Monocyte-derived cystatin F increased Abeta deposition and exacerbated cognitive deficits in APP/PS1 mice. Furthermore, secreted cystatin F in the plasma of AD patients has a dimeric structure that is closely related to clinical signs of AD. Moreover, we noted that the cystatin F dimer blocks the phagocytosis of Abeta by monocytes. Mechanistically, the cystatin F dimer physically interacts with Abeta to inhibit its recognition and internalization by monocytes through certain amino acid interactions between the cystatin F dimer and Abeta. We found that high levels of the cystatin F dimer protein in blood contributed to amyloid pathology and cognitive deficits as a risk factor in 5XFAD mice. CONCLUSIONS: Our findings highlight that the cystatin F dimer plays a crucial role in regulating Abeta metabolism via its peripheral clearance pathway, providing us with a potential biomarker for diagnosis and potential target for therapeutic intervention. |
