Browsing by Author "Ghannam, Abdulaziz Mohammed"

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Effect of OPTN and OPTN phospho mutants on the innate immune response to Toll-like receptor and NOD Like receptor stimulation
(2023) Ghannam, Abdulaziz Mohammed; Smith, Andrew
Inflammatory diseases represent a large section of conditions affecting the oral cavity. Many chronic diseases may last for life, with their causal factors deemed multifactorial or unknown. Optineurin (OPTN) is an adaptor protein with multiple roles in cellular function. One of its primary roles is related to the promotion of proinflammatory cytokines and chemokines expression and secretion. Gene mutations within OPTN have been identified to contribute to multiple inflammatory or autoimmune conditions. The main aim of this study is to investigate a link between OPTN and NOD2 activation with MDP in the form of a phosphorylation site in OPTN structure. Also, to test the ability of this phosphorylation site to impact NOD2 activation of the NFkB pathway through phosphoproteomics modification in OPTN structure. Finally, measure the significance of this link to inflammation and bacterial response in the form of cytokines release. During this study, I identified a novel phosphorylation site in OPTN that impacts the NFkB pathway by activating the bacterial receptor NOD2. THP-1, the human monocytic cell line, was genetically modified to express human OPTN tagged with EGFP on its N-terminus (THP- 1 OPTN). The THP-1 OPTN cell line was utilised to study protein localisation intracellularly, immunoprecipitation and phosphoproteomics. I identified a novel Serine 526 (Ser526) phosphorylation site induced after NOD2 stimulation with muramyl dipeptide (MDP). To determine the functional consequence of Ser526, phosphorylation site-directed mutagenesis was used to introduce an amino acid substitution at position 525 in the EGFPOPTN, resulting in phosphomimetic amino acids. Phospho-dead and phospho-active OPTN constructs were generated by switching Ser526 to Ala526 (S526A) and Glu526 (S526E), 5 respectively. In addition, stable THP-1 cell lines were produced (THP-1 S526A and THP-1 S526E), and the impact of these mutations on the immune response downstream of NOD2 and Tolllike receptors (TLR) was investigated. THP-1 S526E cells demonstrated a significant elevation in the induction and secretion of proinflammatory cytokines upon NOD2 stimulation. THP-1 S526A ability to secrete cytokines was significantly impeded upon stimulation. The phosphorylation at Ser526 seemed to augment TLR signalling resulting in a significant boost in the induction and release of cytokines. These studies have identified a novel role for OPTN in the immune response downstream of NOD2. The phosphorylation of Ser526 upon NOD2 activation acts as an immune booster which can cooperate with other receptors, such as TLRs, upon bacterial challenge. Mutations in OPTN and NOD2 are associated with a host of human diseases, and the relevance of this pathway to these conditions warrants further investigation.
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Physiotherapy in the prevention and management of radiotherapy-induced trismus: a critical review
(2015) Ghannam, Abdulaziz Mohammed; Fedele, Stefano
Aims: The aim of this study is to review current evidence on the use of physiotherapy in the prevention and treatment of Radiotherapy-induced trismus in Head and Neck cancer patients (HNC) and report on its efficacy in such condition. Methods: We searched the digital databases of Medline, Embase, Cochrane Library and PubMed for articles published in the period from January 1980 to July 2015 that were related to the topic. The key word used were trismus, radiotherapy induced trismus, radiotherapy induced trismus, head and neck cancer and physiotherapy in titles, abstract and Mesh terms. Additional articles identified by tracing any literature containing preventive methods or managements for trismus in patients of head and neck cancer. Results: 11 articles related to the use of physiotherapy as a management and/or preventive tool for RT-induced trismus were identified of which 3 were randomized controlled trials, 2 were controlled trails, 5 were cohort studies and 1 were prospective case series. Modalities of physiotherapy used in these studies included unassisted exercises, tongue blade assisted exercises, Therabite® Jaw Motion Rehabilitation System, Dynasplint Trismus System, Engström jaw mobilizing device. Current evidence suggests that passive jaw mobilization devices can be beneficial in individuals with RT-induced trismus, whereas unassisted exercises and active range motion techniques seems to provide less clear benefits. Conclusion: This review demonstrate the various techniques of physiotherapy in prevention and management of radiotherapy induced trismus and its efficacy. Physiotherapy is a valid noninvasive method to manage radiotherapy induced trismus that need more investigation to maximise its benefits. Passive jaw mobilization devices and structured physiotherapy protocols coupled with positive motivation are effective in increasing mouth opening in HNC treated or planned to be treated with radiotherapy.
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