Dental Aspects of Necroptosis
Periodontitis is an inflammatory process being associated with necroptosis, a molecular process that requires caspase-8 for activation of receptor-interacting serine/threonine-protein kinase 1 (RIPK1), RIPK3 and mixed-lineage kinase domain-like protein (MLKL). MLKL mediates one programmed cell death process, the necroptosis pathway. In periodontitis, necroptosis is supposed to influence bacterial infection progression and presumably plays a role in maintaining the homeostasis in the periodontal niche. In gingival tissues collected from patients with untreated chronic periodontitis, elevated levels of MLKL and phosphorylated MLKL were observed. Moreover, periodontitis models showed increased phosphorylated MLKL in biopsies while pharmacological blocking MLKL reduced inflammatory osteolysis. There is thus accumulating evidence that necroptosis is among the pathologic mechanisms of periodontitis. This evidence, however, remains descriptive and the role of MLKL in the progression and regeneration of the periodontal tissue is unknown. Thus, no information is available if MLKL signaling is required for the healing of extraction sockets and the process of periodontal inflammatory osteolysis. Thus, it is relevant to investigate the role of MLKL in alveolar bone regeneration. Moreover, there is a demand to further study the involvement of MLKL in periodontal destruction upon inflammation. Based on this missing knowledge we have identified three research objectives:
- To study necroptosis in the context of simulated inflammation in vitro. The first milestone is to establish in vitro models with necroptosis inhibitors and identify MLKL activity. We expect to find that MLKL inhibitors reduce the in vitro inflammatory response.
- To study the healing of tooth extraction sockets in MLKL knockout (KO) mice. The second milestone is to perform tooth extraction in MLKL KO and WT animals and perform analysis. We hypothesize that bone regeneration in MLKL KO mice is impaired when compared to WT littermates.
- To study osteolysis upon ligature placement around a molar in MLKL knockout mice. The third milestone is to place ligatures between molars in MLKL KO and WT animals and perform structural analysis. We assume that resorption of alveolar bone is less in MLKL KO mice compared to WT littermates.
Methods and Skills:
cell culture; PCR; ELISA; immunostaining; Western blot; micro-CT
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