Aims: Frontotemporal Dementia (FTD) is caused by frontal-temporal lobar degeneration (FTLD), characterized mainly by brain protein aggregates of tau (FTLD-Tau) or TDP-43 (FTLD-TDP). The clinicopathological heterogeneity makes ante-mortem diagnosis of these pathological subtypes challenging. Our proteomics study showed increased Apolipoprotein L1 (APOL1) levels in CSF from FTD patients, which was prominently expressed in FTLD-Tau. We aimed to understand APOL1 expression in FTLD post-mortem brain tissue and to validate its potential as a CSF biomarker for FTD and its pathological subtypes.
Methods: APOL1 levels were analyzed in the frontal cortex of FTLD (including FTLD-Tau and FTLD-TDP) and non-demented controls by immunohistochemistry (FTLD total = 18 (12 FTLD-Tau and 6 FTLD-TDP); controls = 9), western blot (WB), and a novel prototype ELISA (FTLD total = 44 (21 FTLD-Tau and 23 FTLD-TDP); controls = 9). The association of APOL1 immunoreactivity with phosphorylated Tau (pTau) and TDP-43 (pTDP-43) immunoreactivity was assessed. CSF APOL1 was analyzed in confirmed FTD patients (n = 27, including 12 FTLD-Tau and 15 FTLD-TDP) and controls (n = 15) using the same ELISA.
Results: APOL1 levels were significantly increased in FTLD post-mortem tissue compared to controls as measured by immunohistochemistry, WB, and ELISA. However, no differences between the pathological subtypes were observed. APOL1 immunoreactivity was present in neuronal and glial cells but did not co-localize with pTau or pTDP-43. CSF APOL1 levels were comparable between FTD patients and controls and between pathological subtypes.
Conclusion: APOL1 is upregulated in FTLD pathology irrespective of the subtypes, indicating a role of this novel protein in FTD pathophysiology. The APOL1 levels detected in brain tissue were not mirrored in the CSF, limiting its potential as a specific FTD biofluid-based biomarker using our current immunoassay.
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http://dx.doi.org/10.1016/j.nbd.2022.105813 | DOI Listing |
Biomolecules
December 2024
Department of Medicine and Feinstein Institute for Medical Research, Zucker School of Medicine, Hempstead, NY 11549, USA.
Patients carrying APOL1 risk alleles (G1 and G2) have a higher risk of developing Focal Segmental Glomerulosclerosis (FSGS); we hypothesized that escalated levels of miR193a contribute to kidney injury by activating renin-angiotensin system (RAS) in the APOL1 milieus. Differentiated podocytes (DPDs) stably expressing vector (V/DPD), G0 (G0/DPDs), G1 (G1/DPDs), and G2 (G2/DPDs) were evaluated for renin, Vitamin D receptor (VDR), and podocyte molecular markers (PDMMs, including WT1, Podocalyxin, Nephrin, and Cluster of Differentiation [CD]2 associated protein [AP]). G0/DPDs displayed attenuated renin but an enhanced expression of VDR and Wilms Tumor [WT]1, including other PDMMs; in contrast, G1/DPDs and G2/DPDs exhibited enhanced expression of renin but decreased expression of VDR and WT1, as well as other PDMMs (at both the protein and mRNA levels).
View Article and Find Full Text PDFClin Transplant
December 2024
Department of Surgery I Center for Biomedical Ethics and Society, Vanderbilt University Medical Center, Nashville, Tennessee, USA.
Pregnancy Hypertens
December 2024
Department of Genetics, Genomics, and Informatics, University of Tennessee Health Science Center, Memphis, TN, United States. Electronic address:
Background: Preeclampsia is a hypertensive disorder in pregnancy known to increase the risk of mortality and other pregnancy-related issues, such as prematurity. Currently, there no known prophylactics or treatment options available for preeclampsia. More research is needed to better understand factors that increase preeclampsia risk.
View Article and Find Full Text PDFNephrol Dial Transplant
October 2024
Department of Twin Research & Genetic Epidemiology, King's College London, UK.
Background: Apolipoprotein L1 (APOL1) high-risk variants are major determinants of chronic kidney disease (CKD) in people of African ancestry. Previous studies have identified epigenetic changes in relation to kidney function and CKD, but not in individuals with APOL1 high-risk genotypes. We conducted an epigenome-wide analysis of CKD and estimated glomerular filtration rate (eGFR) in in people of African ancestry and APOL1 high-risk genotypes with HIV.
View Article and Find Full Text PDFMol Genet Genomic Med
August 2024
Experimental Medicine Centre, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
Background: The highest mortality and morbidity worldwide is associated with atherosclerotic cardiovascular disease (ASCVD), which has in background both environmental and genetic risk factors. Apolipoprotein L1 (APOL1) variability influences the risk of ASCVD in Africans, but little is known about the APOL1 and ASCVD in other ethnic groups.
Methods: To investigate the role of APOL1 and ASCVD, we have genotyped four (rs13056427, rs136147, rs10854688 and rs9610473) APOL1 polymorphisms in a group of 1541 male patients with acute coronary syndrome (ACS) and 1338 male controls.
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