Biology subjects

Ghanem, A.

Publications and source records attributed to Ghanem, A..

3 recordsLinked to original sources

bioRxiv2025

The secreted Nimrod NimB1 negatively regulates early steps of apoptotic cell phagocytosis in Drosophila

Efferocytosis, the efficient clearance of apoptotic cells (ACs) by phagocytes, is vital for maintaining tissue homeostasis. Here, we reveal the role of the secreted protein NimB1 in reducing apoptotic cell recognition and binding in the early stages of efferocytosis. NimB1 is expressed in macrophages (also called plasmatocytes) and binds to ACs in a phosphatidylserine-dependent manner. Structural analysis shows that NimB1 shares striking similarities with the bridging molecule NimB4, and possesses two phosphatidylserine-binding motifs, supporting its role in efferocytosis. Larval macrophages of NimB1 null mutants display a hyper-phagocytic phenotype characterized by increased engulfment of ACs. Confocal imaging reveals that NimB1 specifically inhibits early steps in internalization of ACs, but does not impact phagosome maturation. We find that NimB1 is a secreted factor that negatively regulates efferocytosis, antagonizing the role of NimB4. Our study and the analogous opposing roles of Draper Isoforms II and I in efferocytosis suggest that a balance of negative and positive regulators allows optimization of the rate of apoptotic cell clearance by macrophages.

immunology↗

bioRxiv2023

Inhibition of Herpes simplex virus and Vesicular stomatitis virus Proliferation by Lactiplantibacillus planterum and star anise Extract Is Associated with Induction of MX gene expression

PurposeThere is an immense need to develop new antiviral compounds that are effective and have little side effects. Natural compounds provide a good candidate that is gaining popularity. Probiotics as Lactiplantibacillus plantarum and plant-derived medicines as star anise extract have been investigated to treat viral diseases, cancer, and inflammation. This work aimed to investigate the antiviral effect of probiotics (Lactiplantibacillus plantarum) and (star anise) against Herpes simplex virus type 1(HSV-1) and Vesicular stomatitis virus (VSV). Patients and methodsLactiplantibacillus plantarum and star anise extract had been prepared and tested against vero cell lines for cytotoxicity assay. The antiviral effect of L. plantarum and star anise against HSV-1 and VSV was evaluated by titration calculation (TCID50). The expression of MX genes were measured in infected cells before and after treatment with L. plantarum and star anise. ResultsWe found that L. planterum is more effective against HSV-1 and caused 2.5 log reduction in virus titre while star anise extract is more effective against VSV and caused 1.25 log reduction in virus titre. Evaluation of MX genes expression revealed higher expression in HSV-1 infected cell treated with L. planterum and VSV infected cells treated with star anise extract. ConclusionL. planterum and star anise could be useful antiviral natural compounds that have minimal side effects Plain language SummaryBoth Herpes simplex virus type 1(HSV-1) and Vesicular stomatitis virus (VSV) caused infection characterized by lytic lesions. Lactiplantibacillus plantarum and star anise had shown promising antiviral effects. So, we investigated the antiproliferative effect of L. plantarum and star anise against HSV-1 and VSV by assessment of virus titre before and after treatment and assessment of MX gene coding for antiviral proteins. We found that L. plantarum and star anise could inhibit proliferation of HSV-1 and VSV and increase expression of MX gene. L. plantarum and star anise could be good antiviral candidate.

microbiology↗

bioRxiv2019

Mitochondrial fusion in reactive astrocytes coordinates local metabolic domains to promote vascular repair

Astrocytes have emerged for playing important roles in brain tissue repair, however the underlying mechanisms remain poorly understood. We show that acute injury and blood-brain barrier disruption trigger the formation of a prominent mitochondrial-enriched compartment in astrocytic end-feet which enables vascular remodeling. Integrated imaging approaches revealed that this mitochondrial clustering is part of an adaptive response regulated by fusion dynamics. Astrocyte-specific conditional deletion of Mitofusin 2 (Mfn2) suppressed perivascular mitochondrial clustering and disrupted mitochondria-ER contact sites. Functionally, two-photon imaging experiments showed that these structural changes were mirrored by impaired mitochondrial Ca2+ uptake leading to abnormal cytosolic transients within end-feet in vivo. At the tissue level, a compromised vascular complexity in the lesioned area was restored by boosting mitochondrial-ER perivascular tethering in MFN2-deficient astrocytes. These data unmask a crucial role for mitochondrial dynamics in coordinating astrocytic local domains and have important implications for repairing the injured brain.

cell biology↗