Omar Samir

Mr. Omar Samir

orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2020 in Biochemical and Biophysical Research Communications
Verified
Journal Article
Closed access
Manoj Kumar YadavManoj Kumar Yadav
Manoj Kumar Yadav
YIYuri Inoue
Yuri Inoue
ANAya Nakane-Otani
Aya Nakane-Otani
YTYuki Tsunakawa
Yuki Tsunakawa
HJHyojung Jeon
Hyojung Jeon
MHMichito Hamada
Michito Hamada

11 December 2020 in Journal of Biomolecular Structure and Dynamics
Verified
Journal Article
Closed access
Mai LabibMai Labib
Mai Labib
MAM. K. Amin
M. K. Amin
AAA. M. Alzohairy
A. M. Alzohairy
mohamed elashtokhymohamed elashtokhy
mohamed elashtokhy
OSOmar Samir
Omar Samir
FAFatthy Mohamed Abdeltawab
Fatthy Mohamed Abdeltawab
The spread of fungal growth causes enormous economic, agricultural, and health problems for humans, such as Aspergillus sp., which produce aflatoxins. Thus, the inhibition of aflatoxin production became a precious target. In this research, the thioesterase (TE) domain from Polyketide synthase enzyme was selected to employ the in silico docking, using AutoDock Vina, against 623 natural compounds from the South African natural compound database (SANCDB), to identify potential inhibitors that can selectively inhibit thioesterase domain. The top ten inhibitors components were pinocembrin, typhaphthalide, p-coumaroylputrescine, dilemmaone A, 9-angelylplatynecine, 2,4,6-octatrienal, 4,8-dichloro-3,7-dimethyl-, (2e,4z,6e)-, lilacinobiose, 1,3,7-octatriene, 5,6-dichloro-2-(dichloromethyl)-6-methyl-, [r*,s*-(e)]-(-)- (9ci), lilacinobiose, 1,3,7-octatriene, 5,6-dichloro-2-(dichloromethyl)-6-methyl-, [r*,s*-(e)]-(-)- (9ci), 1,3,7-octatriene, 1,5,6-trichloro-2-(dichloromethyl)-6-methyl-, [r*,s*-(z,e)] and 9-angelylhastanecine and that depending on the lowest binding energy, the best chemical interactions and the best drug-likeness. The results of those components gave successful inhibition with the thioesterase domain. So, they can be used for inhibition and controlling aflatoxin contamination of agriculture crop yields, specially, pinocembrin which gave promising results. Communicated by Ramaswamy H. Sarma

9 October 2025 in Proceedings of the National Academy of Sciences
Verified
Journal Article
Open access
ANAiri Nishida
Airi Nishida
JNJun Nagai
Jun Nagai
MHMadeline Hastings
Madeline Hastings
KZKendall Zaleski
Kendall Zaleski
MSMarie Sasaki
Marie Sasaki
JBJoshua A. Boyce
Joshua A. Boyce
Platelets amplify type 2 inflammation (T2I) through incompletely understood mechanisms. Depletion of platelets markedly attenuated mast cell (MC) activation in a model of aspirin exacerbated respiratory disease (AERD) that depends on IL-33 and cysteinyl leukotrienes (cysLTs). We demonstrate an IL-33-driven feed-forward loop between platelets and MCs. IL-33 neutralization prevented increases in cysLTs and CXCL7, a platelet activation marker, in bronchoalveolar lavage (BAL) fluid from AERD-like mice in response to aspirin challenges. BAL fluid concentrations of PGD 2 correlated strongly with both CXCL7 and MC tryptase in subjects with severe asthma. Platelets amplified PGD 2 and LTC 4 productions by IL-33-stimulated mouse bone marrow–derived MCs (BMMCs), which induced release of CXCL7 and expression of CD62P by platelets. Deletions of MC-specific LTC 4 or platelet-specific type 2 cysLT receptor (CysLT 2 R) completely eliminated both platelet activation and the amplification of PGD 2 and LTC 4 generation by MCs. Platelet-derived ADP/ATP and MC-associated P2Y 1 receptors were essential. These findings identify an innate immune pathway involving MC–platelet interplay that may drive IL-33-dependent immunopathology in asthma.

Verified
Journal Article
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OSOmar Samir
Omar Samir
NKNaohiro Kobayashi
Naohiro Kobayashi
TNTeppei Nishino
Teppei Nishino
MSMennatullah Siyam
Mennatullah Siyam
Manoj Kumar YadavManoj Kumar Yadav
Manoj Kumar Yadav
MHMichito Hamada
Michito Hamada
MAFB is a basic leucine zipper (bZIP) transcription factor specifically expressed in macrophages. We have previously identified MAFB as a candidate marker for tumor-associated macrophages (TAMs) in human and mouse models. Here, we analyzed single-cell sequencing data of patients with lung adenocarcinoma obtained from the GEO database (GSE131907). Analyzed data showed that general macrophage marker CD68 and macrophage scavenger receptor 1 (CD204) were expressed in TAM and lung tissue macrophage clusters, while transcription factor MAFB was expressed specifically in TAM clusters. Clinical records of 120 patients with lung adenocarcinoma stage I (n = 57), II (n = 21), and III (n = 42) were retrieved from Tsukuba Human Tissue Biobank Center (THB) in the University of Tsukuba Hospital, Japan. Tumor tissues from these patients were extracted and stained with anti-human MAFB antibody, and then MAFB-positive cells relative to the tissue area (MAFB+ cells/tissue area) were morphometrically quantified. Our results indicated that higher numbers of MAFB+ cells significantly correlated to increased local lymph node metastasis (nodal involvement), high recurrence rate, poor pathological stage, increased lymphatic permeation, higher vascular invasion, and pleural infiltration. Moreover, increased amounts of MAFB+ cells were related to poor overall survival and disease-free survival, especially in smokers. These data indicate that MAFB may be a suitable prognostic biomarker for smoker lung cancer patients.

25 July 2021 in Veterinary World
Verified
Journal Article
Open access
Sara T. ElazabSara T. Elazab
Sara T. Elazab
OSOmar Samir
Omar Samir
MAMarwa Mossa Abass
Marwa Mossa Abass
Background and Aim: Fipronil (FPN) is a potent pesticide that is heavily used around the world in agriculture. However, its irrational use could potentially have deleterious effects on animals and humans. The present study aimed to investigate the ability of sitagliptin (Sit) and losartan (LOS), when used both individually or concurrently, to guard rat liver against the acute hepatotoxicity caused by FPN. Materials and Methods: Forty-two adult male Wistar rats were equally divided into seven groups (6/group). Group I (control) received normal saline (0.5 mL/rat, vehicle for all treatments) by gavage once daily for 10 days. Group II received oral Sit (10 mg/kg body weight [BW]) daily for 10 days and Group III received oral LOS (5 mg/kg BW) daily for 10 days. Group IV received oral FPN (19.4 mg/kg BW; 1/5 of the oral LD50) for the past 5 days of the study. Groups V and VI received oral Sit (10 mg/kg BW) and LOS (5 mg/kg BW) daily, respectively, 5 days prior and 5 days during FPN administration (19.4 mg/kg BW). Group VII received oral Sit (10 mg/kg BW) and LOS (5 mg/kg BW) for 10 days with daily FPN during the past 5 days. After the end of the treatment period, the rats were humanely sacrificed and blood and liver tissue samples were collected for biochemical analysis and histopathological and immunohistochemical investigations. Results: FPN administration resulted in elevated alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase serum concentrations as well as increased malondialdehyde levels and reduced catalase, superoxide dismutase, glutathione peroxidase, and glutathione activity. The histopathological investigation showed disorganization of the hepatic cords and focal necrosis of the hepatocytes in FPN-intoxicated rats. Furthermore, the immunohistochemical examination showed that hepatic caspase-3 was overexpressed in the FPN-treated rats. The administration of Sit and LOS before and alongside FPN markedly mitigated the alterations caused by FPN and the hepatoprotective effects were more prominent in the combination group. Conclusion: Sit and LOS, both individually or in combination, confers considerable hepatoprotection against FPN-induced hepatotoxicity.