Faculty Bibliography

Non-human primates have an important translational value given their close phylogenetic relationship to humans. Studies in these animals remain essential for evaluating efficacy and safety of new therapeutic approaches, particularly in aging primates that display Alzheimer's disease (AD) -like pathology. With the objective to improve amyloid-β (Aβ) targeting immunotherapy, we investigated the safety and efficacy of an active immunisation with an Aβ derivative, K6Aβ1-30-NH₂, in old non-human primates. Thirty-two aged (4-10 year-old) mouse lemurs were enrolled in the study, and received up to four subcutaneous injections of the vaccine in alum adjuvant or adjuvant alone. Even though antibody titres to Aβ were not high, pathological examination of the mouse lemur brains showed a significant reduction in intraneuronal Aβ that was associated with reduced microgliosis, and the vaccination did not lead to microhemorrhages. Moreover, a subtle cognitive improvement was observed in the vaccinated primates, which was probably linked to Aβ clearance. This Aβ derivative vaccine appeared to be safe as a prophylactic measure based on the brain analyses and because it did not appear to have detrimental effects on the general health of these old animals.

INTRODUCTION/BACKGROUND:Neurological complications among hospitalized COVID-19 patients may be associated with elevated neurodegenerative biomarkers. METHODS:Among hospitalized COVID-19 patients without a history of dementia (N = 251), we compared serum total tau (t-tau), phosphorylated tau-181 (p-tau181), glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), ubiquitin carboxy-terminal hydrolase L1 (UCHL1), and amyloid beta (Aβ40,42) between patients with or without encephalopathy, in-hospital death versus survival, and discharge home versus other dispositions. COVID-19 patient biomarker levels were also compared to non-COVID cognitively normal, mild cognitive impairment (MCI), and Alzheimer's disease (AD) dementia controls (N = 161). RESULTS:Admission t-tau, p-tau181, GFAP, and NfL were significantly elevated in patients with encephalopathy and in those who died in-hospital, while t-tau, GFAP, and NfL were significantly lower in those discharged home. These markers correlated with severity of COVID illness. NfL, GFAP, and UCHL1 were higher in COVID patients than in non-COVID controls with MCI or AD. DISCUSSION/CONCLUSIONS:Neurodegenerative biomarkers were elevated to levels observed in AD dementia and associated with encephalopathy and worse outcomes among hospitalized COVID-19 patients.

Point-of-care (POC) testing for Toxoplasma infection has the potential to revolutionize diagnosis and management of toxoplasmosis, especially in high-risk populations in areas with significant environmental contamination and poor health infrastructure precluding appropriate follow-up and preventing access to medical care. Toxoplasmosis is a significant public health challenge in Morocco, with a relatively heavy burden of infection and, to this point, minimal investment nationally to address this infection. Herein, we analyze the performance of a novel, low-cost rapid test using fingerstick-derived whole blood from 632 women (82 of whom were pregnant) from slums, educational centers, and from nomad groups across different geographical regions (i.e. oceanic, mountainous) of Morocco. The POC test was highly sensitive and specific from all settings. In the first group of 283 women, sera were tested by Platelia ELISA IgG and IgM along with fingerstick whole blood test. Then a matrix study with 349 women was performed in which fingerstick- POC test results and serum obtained by venipuncture contemporaneously were compared. These results show high POC test performance (Sensitivity: 96.4% [IC95 90.6-98.9%]; Specificity: 99.6% [IC95 97.3-99.9%]), and high prevalence of Toxoplasma infection among women living in rural and mountainous areas, and in urban areas with lower educational levels. The high performance of POC test confirms that it can reduce the need for venipuncture and clinical infrastructure in a low resource setting. It can be used to efficiently perform seroprevalence determinations in large group settings across a range of demographics, and potentially expands healthcare access, thereby preventing human suffering.

Neurofibrillary tangles (NFTs) are a major pathologic hallmark of Alzheimer's disease (AD). Several studies have shown that amyloid β oligomers (Aβo) and tau oligomers mediate their toxicity, in part, via binding to cellular prion protein (PrP^C) and that some anti-PrP antibodies can block this interaction. We have generated a novel monoclonal anti-PrP antibody (TW1) and assessed the efficacy of passive immunization with it in a mouse model of AD with extensive tau pathology: hTau/PS1 transgenic (Tg) mice. These mice were injected intraperitoneally once a week with TW1 starting at 5 months of age. Behavior was assessed at 8 months of age and brain tissue was subsequently harvested for analysis of treatment efficacy at 9 months. Mice treated with TW1 did not show any significant difference in sensorimotor testing including traverse beam, rotarod, and locomotor activity compared to controls. Significant cognitive benefits were observed with the novel object recognition test (ORT) in the immunized mice (two-tailed, t-test p = 0.0019). Immunized mice also showed cognitive benefits on the closed field symmetrical maze (day 1 two-tailed t-test p = 0.0001; day 2 two-tailed t-test p = 0.0015; day 3 two-tailed t-test p = 0.0002). Reduction of tau pathology was observed with PHF-1 immunohistochemistry in the piriform cortex by 60% (two-tailed t-test p = 0.01) and in the dentate gyrus by 50% (two-tailed t-test p = 0.02) in animals treated with TW1 compared to controls. There were no significant differences in astrogliosis or microgliosis observed between treated and control mice. As assessed by Western blots using PHF-1, the TW1 therapy reduced phosphorylated tau pathology (two-tailed t-test p = 0.03) and improved the ratio of pathological soluble tau to tubulin (PHF1/tubulin; two-tailed t-test p = 0.0006). Reduction of tau pathology also was observed using the CP13 antibody (two-tailed t-test p = 0.0007). These results indicate that passive immunization with the TW1 antibody can significantly decrease tau pathology as assessed by immunohistochemical and biochemical methods, resulting in improved cognitive function in a tau transgenic mouse model of AD.

Background: Alzheimer's disease (AD) is a progressive neurodegenerative disease that currently accounts for over 70% of cases of dementia in adults over 65 worldwide, and is the only cause of death among the top ten with no effective treatments. Clinically, AD is characterized by progressive deterioration in memory and other areas of cognitive function. Neuropathologically, the disease is characterized by extracellular aggregations of amyloid-B (AB) and intraneuronal neurofibrillary tangles (NFTS) composed of abnormally phosphorylated tau, causing progressive neuronal death. The aim of this study was to investigate whether the affibody ZSYM73-ABD (a portion of the active antibody molecule) can reverse AD pathology in an AD mouse model, without also causing significant neuroinflammation and/or microhemorrhage.
Method(s): APP/PS1 double transgenic mice were injected twice weekly with either ZSYM-ABD or a non-AB specific affibody, Ztaq2, as a control. Mice underwent behavioral testing and their brains were then sacrificed for immunohistochemistry.
Result(s): Semi-quantitative analysis of amyloid burden, performed using 6E10/4G8 antibodies, showed a statistically significant reduction in amyloid burden in the hippocampus, and a trend towards reduction in amyloid burden in the cortex. Inflammation was assessed using GFAP and Iba1(markers of gliosis) which showed a statistically significant reduction of GFAP in the cortex and in the hippocampus, and a slight reduction of microgliosis in ZSYM73-ABD affibody treated mice. Finally, mice treated with ZSYM73-ABD performed significantly better on a novel object recognition task than control mice, suggesting a correlation between the histological findings above and improvement in cognitive function.
Conclusion(s): In conclusion, this study demonstrates that passive immunization with an affibody molecule improves cognitive function and significantly decreases amyloid burden in the hippocampus of a transgenic mouse model of AD, without inducing inflammation. This has potential implications for treatment of AD in humans

Different strategies for treatment and prevention of Alzheimer's disease (AD) are currently under investigation, including passive immunization with anti-amyloid β (anti-Aβ) monoclonal antibodies (mAbs). Here, we investigate the therapeutic potential of a novel type of Aβ-targeting agent based on an affibody molecule with fundamentally different properties to mAbs. We generated a therapeutic candidate, denoted Z_SYM73-albumin-binding domain (ABD; 16.8 kDa), by genetic linkage of the dimeric Z_SYM73 affibody for sequestering of monomeric Aβ-peptides and an ABD for extension of its in vivo half-life. Amyloid precursor protein (APP)/PS1 transgenic AD mice were administered with Z_SYM73-ABD, followed by behavioral examination and immunohistochemistry. Results demonstrated rescued cognitive functions and significantly lower amyloid burden in the treated animals compared to controls. No toxicological symptoms or immunology-related side-effects were observed. To our knowledge, this is the first reported in vivo investigation of a systemically delivered scaffold protein against monomeric Aβ, demonstrating a therapeutic potential for prevention of AD.

Molecular dynamics (MD) simulation using the AMBER force field has been performed on the neurotensin receptor, a class A type G-protein coupled receptor in its activated conformation co-crystallized with the non-peptide agonists. For structure-based hit molecule identification via natural chemical compound library, orthosteric sites on neurotensin receptor have been mapped by docking using AutoDock4.0 and Vina with the known agonists and antagonists SR48692, SR142948, ML301 and ML314 of the receptor. Furthermore, clustering analysis on the MD trajectories by SIMULAID has been performed to filter receptor conformations for the allosteric binders from the Otava natural compound library. Comparative mappings of contrasting binding region patterns have been done between the crystal structure orthosteric sites as well as the binding regions in the SIMULAID-based cluster center conformations from MD trajectories with the FTmap server using the small organic molecule fragments as the probes. The distinct binding region in the cluster-based conformations in the extra-cellular region of the receptor has been identified for targeted docking by Otava natural chemical compound library using AutoDock4.0 and Vina docking suites to obtain putative allosteric binders. A group of compounds from the Otava library has been identified as showing high free energy in both AutoDock4.0 and Vina docking suites. Biophysical assessments on the natural compound computational hit molecules will be done to identify lead structures from the hit molecules.