Lysine ε-aminolysis and incorporation of sulfhydryl groups into human brain tau 4R/1N and 306VQIVYK311 enhances the formation of beta structures and toxicity.

In the present study, we investigated the effects of N-homocysteine thiolactone (tHcy) modification on expressed and purified tau protein and the synthesized VQIVYK target peptide. The modified constructs were subjected to comprehensive validation using various methodologies, including mass spectrometry. Subsequently, in vivo, in vitro, and in silico characterizations were performed under both reducing and non-reducing conditions, as well as in the presence and absence of heparin as a cofactor. Our results unequivocally confirmed that under reducing conditions and in the presence of heparin, the modified constructs exhibited a greater propensity for aggregation. This enhanced aggregative behavior can be attributed to the disruption of lysine positive charges and the subsequent influence of hydrophobic and p-stacking intermolecular forces. Notably, the modified oligomeric species induced apoptosis in the SH-SY5Y cell line, and this effect was further exacerbated with longer incubation times and higher concentrations of the modifier. These observations suggest a potential mechanism involving reactive oxygen species (ROS). To gain a deeper understanding of the molecular mechanisms underlying the neurotoxic effects, further investigations are warranted. Elucidating these mechanisms will contribute to the development of more effective strategies to counteract aggregation and mitigate neurodegeneration.

A series of caged fluorophores for calibrating light intensity.

Absolute measurement of light intensity is sought for in multiple areas of chemistry, biology, physics, and engineering. It can be achieved by using an actinometer from analyzing the time-course of its reaction extent on applying constant light. However, most reported actinometers exploit the absorbance observable for reporting the reaction extent, which is not very sensitive nor relevant in imaging systems. In this work, we report a series of hydrophobic and hydrophilic caged fluorophores that overcome the preceding limitations. Based on the robust pyranine backbone, they can easily be synthesized on a large scale in one to a few steps. Their brightness increases over illumination and their uncaging cross-sections have been thoroughly characterized upon one- and two-photon excitation. As a demonstration of their use, we calibrated light intensity in various chemical and biological samples, which have been observed with epifluorescence and confocal imaging systems.

Fluorescence to measure light intensity.

Despite the need for quantitative measurements of light intensity across many scientific disciplines, existing technologies for measuring light dose at the sample of a fluorescence microscope cannot simultaneously retrieve light intensity along with spatial distribution over a wide range of wavelengths and intensities. To address this limitation, we developed two rapid and straightforward protocols that use organic dyes and fluorescent proteins as actinometers. The first protocol relies on molecular systems whose fluorescence intensity decays and/or rises in a monoexponential fashion when constant light is applied. The second protocol relies on a broad-absorbing photochemically inert fluorophore to back-calculate the light intensity from one wavelength to another. As a demonstration of their use, the protocols are applied to quantitatively characterize the spatial distribution of light of various fluorescence imaging systems, and to calibrate illumination of commercially available instruments and light sources.

Plasma Cytokines Profile in Subjects with Alzheimer's Disease: Interleukin 1 Alpha as a Candidate for Target Therapy.

Background: Alzheimer's disease (AD) is the main cause of the neurodegenerative disorder, which is not detected unless the cognitive deficits are manifested. An early prediagnostic specific biomarker preferably detectable in plasma and hence non-invasive is highly sought-after. Various hypotheses refer to AD, with amyloid-beta (Aß) being the most studied hypothesis and inflammation being the most recent theory wherein pro-and anti-inflammatory cytokines are the main culprits. Materials and Methods: In this study, the cognitive performance of AD patients (n=39) was assessed using mini-mental state examination (MMSE), AD assessment scale-cognitive subscale (ADAS-cog), and clinical dementia rating (CDR). Their neuropsychiatric symptoms were evaluated through neuropsychiatric inventory-questionnaire (NPI-Q). Moreover, plasma levels of routine biochemical markers, pro-/anti-inflammatory cytokines such as tumor necrosis factor α (TNF-α), interleukin-1 α (IL-1α), IL-1ß, IL-2, IL-4, IL-6, IL-8, IL-12p70, IL-10, Interferon-gamma, chemokines, including prostaglandin E2 (PGE-2), monocyte chemoattractant protein-1, interferon gamma-induced protein 10, Aß peptide species (42, 40) and Transthyretin (TTR) were measured. Results: Our results revealed that Aß 42/40 ratio and TTR were correlated (r=0.367, P=0.037). IL-1α was directly correlated with ADAS-cog (r=0.386, P=0.017) and Aß 40 (r=0.379, P=0.019), but was inversely correlated with IL-4 (r=-0.406, P=0.011). Negative correlations were found between MMSE and PGE2 (r=-0.405, P=0.012) and TNF-α/ IL-10 ratio (r=-0.35, P=0.037). CDR was positively correlated with both PGE2 (r=0.358, P=0.027) and TNF-α (r=0.416, P=0.013). There was a positive correlation between NPI-caregiver distress with CDR (r=0.363, P=0.045) and ADAS-cog (r=0.449, P=0.019). Conclusion: Based on the observed correlation between IL-1α, as a clinical moiety, and ADAS-cog, as a clinical manifestation of AD, anti-IL-1α therapy in AD could be suggested.

Functional improvement and immune-inflammatory cytokines profile of ischaemic stroke patients after treatment with boswellic acids: a randomized, double-blind, placebo-controlled, pilot trial.

Ischaemic stroke represents one of the main causes of disability. According to the broad investigations, it is widely assumed that the contribution of inflammatory mediators is strongly involved in its pathogenesis. Hence, it seems that stroke treatment needs more efficient and inflammatory-targeted compounds to modulate inflammatory-related pathways. Such strategies paved the way to achieve better clinical outcomes along with conventional therapies. Boswellic acids (BAs), the main bioactive compounds of Boswellia sp. resin; are triterpenoids with well-documented anti-inflammatory properties. Compared with NSAIDs, BAs cross blood-brain barrier yet they do not cause serious gastrointestinal adverse effects. Considering BAs anti-inflammatory features, we conducted a randomized double-blind placebo-controlled pilot trial of these compounds as a supplementary therapy. This trial randomized 80 ischaemic stroke patients (40-80-years old) with a 4-20 score according to the National Institutes of Health Stroke Scale (NIHSS), within 72 h of neurological sign onset, in 1-month follow-up period. We assessed NIHSS as primary and plasma levels of TNF-α, IL-1α, IL-1ß, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IFN-γ, IP-10, MCP-1, 8-isoprostane, and PGE2 as secondary outcomes. According to NIHSS evaluation, patients who were allocated to BA group had a significant recovery in neurological function during the 1-month follow-up, compared with the placebo. The levels of plasma inflammatory markers were significantly decreased in BA group after 7 days of intervention in TNF-α, IL-1ß, IL-6, IL-8, and PGE2. As a preliminary controlled trial in ischaemic stroke, BAs could improve clinical outcome in the early phases of stroke along with promising changes in plasma inflammatory factors.Clinical trial registrationhttps://www.irct.ir Unique identifier: IRCT20170315033086N5. IRCT is a primary registry in the WHO registry network (https://www.who.int/ictrp/network/primary/en/).