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16 result(s) for "Elfarrash, Sara"
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Polo-like kinase 2 inhibition reduces serine-129 phosphorylation of physiological nuclear alpha-synuclein but not of the aggregated alpha-synuclein
Accumulation of aggregated alpha-synuclein (α-syn) is believed to play a pivotal role in the pathophysiology of Parkinson’s disease (PD) and other synucleinopathies. As a key constituent of Lewy pathology, more than 90% of α-syn in Lewy bodies is phosphorylated at serine-129 (pS129) and hence, it is used extensively as a marker for α-syn pathology. However, the exact role of pS129 remains controversial and the kinase(s) responsible for the phosphorylation have yet to be determined. In this study, we investigated the effect of Polo-like kinase 2 (PLK2) inhibition on formation of pS129 using an ex vivo organotypic brain slice model of synucleinopathy. Our data demonstrated that PLK2 inhibition has no effect on α-syn aggregation, pS129 or inter-neuronal spreading of the aggregated α-syn seen in the organotypic slices. Instead, PLK2 inhibition reduced the soluble pS129 level in the nuclei. The same finding was replicated in an in vivo mouse model of templated α-syn aggregation and in human dopaminergic neurons, suggesting that PLK2 is more likely to be involved in S129-phosphorylation of the soluble physiological fraction of α-syn. We also demonstrated that reduction of nuclear pS129 following PLK2 inhibition for a short time before sample collection improves the signal-to-noise ratio when quantifying pS129 aggregate pathology.
Novel anticancer effect of substituted imidazole derivatives against urothelial carcinoma: integrating In vitro screening and molecular docking for target kinases
Four novel substituted imidazole derivatives—5a (Kim-161), 5b (Kim-111), 5c (Kim-261), and 5d (Kim-231) were evaluated for their antiproliferative activity against urothelial carcinoma. Among these, the two derivatives Kim-161 (5a) and Kim-111 (5b) demonstrated potent cytotoxicity against the T24 transitional carcinoma cell line, with IC 50 values of 56.11 µM and 67.29 µM, respectively, as determined by MTT assay. Further mechanistic investigations revealed that these compounds modulate key pathways involved in cancer progression including cell cycle regulation; (p53), oncogenic signaling (Kras), cell apoptosis; (BAX and caspase 3), inflammatory response (Interleukin 6 (IL6), Tumor Necrosis Factor alpha (TNFα), and Nuclear Factor kappa B (NF-κB), autophagy regulation (phosphoinositide 3-kinase signaling (PIK3CA) and its targets protein kinase Akt and mammalian target of rapamycin (mTOR) and metastasis (Matrix metalloproteinase-9 (MMP-9)). Molecular docking and dynamic simulations against key cancer targets PTK6, FLT3, and BCL-2 revealed exceptional binding affinity and stable protein-ligand complexes. Furthermore, these compounds exhibited favorable drug-like properties, including optimal physicochemical and pharmacokinetic profiles. This integrated approach, combining the in vitro validation and computational modeling, places Kim-161 and Kim-111 as promising lead compounds for targeted urothelial carcinoma therapy. The findings underscore the therapeutic potential of dual kinase/tubulin inhibition in combating aggressive malignancies, offering a robust foundation for further preclinical development.
Anti-proliferative activity of RIHMS-Qi-23 against MCF-7 breast cancer cell line is through inhibition of cell proliferation and senescence but not inhibition of targeted kinases
Background Breast cancer is the most common malignancy globally, and is considered a major cause of cancer-related death. Tremendous effort is exerted to identify an optimal anticancer drug with limited side effects. The quinoline derivative RIMHS-Qi-23 had a wide-spectrum antiproliferative activity against various types of cancer cells. Methods In the current study, the effect of RIMHS-Qi-23 was tested on MCF-7 breast cancer cell line to evaluate its anticancer efficacy in comparison to the reference compound doxorubicin. Results Our data suggest an anti-proliferative effect of RIMHS-Qi-23 on the MCF-7 cell line with superior potency and selectivity compared to doxorubicin. Our mechanistic study suggested that the anti-proliferative effect of RIMHS-Qi-23 against MCF-7 cell line is not through targeted kinase inhibition but through other molecular machinery targeting cell proliferation and senescence such as cyclophlin A, p62, and LC3. Conclusion RIMHS-Qi-23 is exerting an anti-proliferative effect that is more potent and selective than doxorubicin.
Impairment of Nrf2 signaling in the hippocampus of P301S tauopathy mice model aligns with the cognitive impairment and the associated neuroinflammation
Mice transgenic for human P301S tau protein exhibit many characteristics of the human tauopathies, including the formation of abundant hyperphoshorylated tau filaments, the associated neuroinflammation and disease phenotype. However, the exact underpinning mechanisms are still not fully addressed that hinder our understanding of the tauopathy diseases and the development of possible therapeutic targets.Methods: In the current study, hippocampus from three disease time points (2, 4 and 6 months) of P301S mice were further characterized in comparison to the age and sex matched control wild type mice (WT) that do not express the transgene. Different spectrum of hippocampal dependent cognitive tests, biochemical and pathological analysis were conducted to understand the disease progression and the associated changes in each stage. Results: Cognitive impairment was manifested as early as 2 months age, prior to the identification of tau aggregation and phosphorylation by immunostaining. P301S mice manifested an increased pro-inflammatory related changes at mRNA transcription level (IL-1b and IL17A) with the progression of the disease and when compared to the WT mice of the same age. Among the identified genes in the current study, the nuclear factor (erythroid-derived 2)-like 2 (Nrf2) genes expression that is considered as the master regulator of an endogenous inducible defense system was significantly impaired in P301S mice by 4 and 6 months when compared to healthy WT controls. A data that was also supported by the immunostaining of the serial brain sections including the both brain stem and hippocampus. The current result is suggesting that the downregulation of Nrf2 gene and the impaired Nrf2 dependent anti-inflammatory mechanisms in P301S mice brain is possibly contributing -among other factors- in the neuroinflammation and tauopathy, and that modulation of Nrf2 signaling impairments can be further investigated as a promising potential therapeutic target for tauopathy.
Organotypic slice culture model demonstrates inter-neuronal spreading of alpha-synuclein aggregates
Here we describe the use of an organotypic hippocampal slice model for studying α-synuclein aggregation and inter-neuronal spreading initiated by microinjection of pre-formed α-synuclein fibrils (PFFs). PFF injection at dentate gyrus (DG) templates the formation of endogenous α-synuclein aggregates in axons and cell bodies of this region that spread to CA3 and CA1 regions. Aggregates are insoluble and phosphorylated at serine-129, recapitulating Lewy pathology features found in Parkinson’s disease and other synucleinopathies. The model was found to favor anterograde spreading of the aggregates. Furthermore, it allowed development of slices expressing only serine-129 phosphorylation-deficient human α-synuclein (S129G) using an adeno-associated viral (AAV) vector in α-synuclein knockout slices. The processes of aggregation and spreading of α-synuclein were thereby shown to be independent of phosphorylation at serine-129. We provide methods and highlight crucial steps for PFF microinjection and characterization of aggregate formation and spreading. Slices derived from genetically engineered mice or manipulated using viral vectors allow testing of hypotheses on mechanisms involved in the formation of α-synuclein aggregates and their prion-like spreading.
Cerebrolysin recovers diaphragmatic function and reduces injury-associated astrogliosis following a cervical spinal cord hemi-section injury in rats
BackgroundSpinal cord injury (SCI) is widely considered the most disastrous medical condition. With no available treatment to date, SCI continues to cause disabilities to the patients and affect their own and their caregivers' quality of life. Cerebrolysin (CBL) is a neuropeptide preparation derived from purified brain proteins with suggested neuroprotective and neurotrophic properties. CBL showed earlier the ability to target multiple pathways that helped in the improvement of the recovery following different groups of neurological diseases and injuries, including ischemic stroke, traumatic brain injuries, and even neurodegenerative diseases. In the current study, the neuroprotective effect of CBL following a SCI is called into question using a rat model of spinal cord cervical hemi-section validated earlier by our lab and others. Using 32 rats divided into four groups randomly, CBL treatment was implemented for either 7 or 21 days duration, following the cervical spinal cord hemi-section.ResultsFollowing the CBL treatment, rats with cervical cord hemi-section showed functional improvement of diaphragmatic muscle as recorded by electromyography (EMG). In addition, the histopathological assessment of the spinal cord showed improved neuronal viability and reduced astrogliosis at the site of the injury compared to the non-treated group. 21-day treatment showed significant improvement when compared to the shorter 7-day regimen.ConclusionOur data suggest that CBL is capable of protecting and regenerating anterior horn motor neurons with functional recovery of diaphragmatic muscle functions in rats, suggesting the potential use of CBL for future regenerative and neuroprotective therapy following SCI.
MJF-14 proximity ligation assay detects early non-inclusion alpha-synuclein pathology with enhanced specificity and sensitivity
α-Synuclein proximity ligation assay (PLA) has proved a sensitive technique for detection of non-Lewy body α-synuclein aggregate pathology. Here, we describe the MJF-14 PLA, a new PLA towards aggregated α-synuclein with unprecedented specificity, using the aggregate-selective α-synuclein antibody MJFR-14-6-4-2 (hereafter MJF-14). Signal in the assay correlates with α-synuclein aggregation in cell culture and human neurons, induced by α-synuclein overexpression or pre-formed fibrils. Co-labelling of MJF-14 PLA and pS129-α-synuclein immunofluorescence in post-mortem cases of dementia with Lewy bodies shows that while the MJF-14 PLA reveals extensive non-inclusion pathology, it is not sensitive towards pS129-α-synuclein-positive Lewy bodies. In Parkinson’s disease brain, direct comparison of PLA and immunohistochemistry with the MJF-14 antibody shows widespread α-synuclein pathology preceding the formation of conventional Lewy pathology. In conclusion, we introduce an improved α-synuclein aggregate PLA to uncover abundant non-inclusion pathology, which deserves future validation with brain bank resources and in different synucleinopathies.
APOE genetic variability in an Egyptian cohort of PD
The apolipoprotein E (APOE) gene, encompassing three alleles (ε2, ε3, ε4), is a critical player in lipid metabolism and has been extensively studied for its role in neurodegenerative diseases. This study examines APOE genetic variability and its association with PD in an Egyptian cohort. A total of 891 participants, including 422 PD patients and 469 healthy controls, were included in this study. APOE genotyping was performed using Kompetitive Allele Specific PCR (KASP) to detect the rs429358 and rs7412 SNPs, which define the APOE alleles. APOE alleles were categorized based on the genotypes into ε2, ε3, and ε4 groups. Clinical assessments of PD patients included age at onset, disease severity (MDS-UPDRS), and demographic factors. Statistical analyses compared APOE distributions between PD and control groups and examined associations with clinical variables. The ε3 allele was the most prevalent in the cohort (77.3%), aligning with global and African trends. The ε2 allele was observed in 11.4%, and the ε4 allele in 11.3%, with both frequencies being lower than reported African estimates. The ε3/ε3 genotype was predominant in both PD patients (72.51%) and controls (72.07%). The ε4/ε4 genotype was absent in PD cases and rare among controls (0.64%). No significant association was found between APOE genotypes and PD risk, age at onset, or disease severity. Our findings do not support a significant role for APOE in PD susceptibility or severity in Egyptians.
Early detection of cochlear hearing loss in rheumatoid arthritis patients: a cross-sectional study
Background Rheumatoid arthritis (RA) is an inflammatory autoimmune disorder that has cardinal articular and peri-articular symptoms. Extra-articular manifestations (EAMs) are also reported among RA patients. In the current study, we assessed hearing function in 50 RA patients. An extensive audiological assessment including pure tone audiometry (PTA), extended high-frequency audiometry (EHFA), tympanometry, and acoustic reflex in addition to the oto-acoustic emission (OAEs) were done. Results Our data demonstrates that among the 50 participants with median disease duration of 8 years, about 80% had normal hearing using PTA and EHFA. However, 46% of them had—interestingly—demonstrated absent OAEs, suggesting early stages of cochlear hearing loss. Conclusion We conclude that rheumatoid arthritis can cause hearing impairment that can be early diagnosed by TEOAEs.
The p.Gly2019Ser is a common LRRK2 pathogenic variant among Egyptians with familial and sporadic Parkinson’s disease
The impact of LRRK2 variants on the risk of Parkinson’s disease in Egyptians remains unknown. We examined 1210 Egyptians (611 PD patients and 599 controls) from 16 governorates across Egypt for 12 LRRK2 pathogenic variants. The p.Gly2019Ser was the only variant detected, with a prevalence of 4.1% in sporadic cases, 6.5% in familial cases, and 0.68% in controls. Among p.Gly2019Ser carriers, all were heterozygous bar one homozygous patient, and all shared the common haplotype 1. Demographics and UPDRS scores did not differ between carriers and non-carriers, with most patients being males and developed PD in their fifties. Young and Early-onset PD prevalence was 37.5% in carriers and 33% in non-carriers. Familial cases were 16.6% in carriers and 11.5% in non-carriers. This study affirms that like other Mediterranean populations, Egyptians with PD have a higher prevalence of the p.Gly2019Ser variant compared to the global average. LRRK2 inhibitors could be promising therapeutic options for further exploration in this population.