Date on Master's Thesis/Doctoral Dissertation
Anatomical Sciences and Neurobiology
Anatomical Sciences and Neurobiology, MS
Committee Co-Chair (if applicable)
oxidative stress; apoptosis; skeletal muscle; necroptosis
Background: Tumor necrosis factor (TNF)-like weak inducer of apoptosis (TWEAK) is a proinflammatory cytokine belonging to the TNF super family. TWEAK produces a variety of cellular responses through the binding to fibroblast growth factor inducible 14 (Fn14), a member of TNF receptor superfamily. Although Fn14 lacks a death domain, TWEAK has been found to induce apoptosis in some cell types by perturbing the activity of certain pathways such as TNF-receptor signaling. TWEAK is also known to regulate proliferation and differentiation of myogenic cells. We have previously reported that the TWEAK-Fn14 system causes skeletal muscle wasting both in vitro and in vivo. In addition, it has been reported that TWEAK is a mediator of atrophy in disuse conditions such as denervation. However, it remains unknown whether TWEAK can affect the viability of muscle cells. Hypothesis: TWEAK induces oxidative stress and cell death in myotube cultures. Methods: We used primary myogenic cells and biochemical assays to study the effects of recombinant TWEAK protein on the survival of cultured mouse primary myotubes. Results: Our results demonstrate that TWEAK reduces myotube viability in a dose-dependent manner evident by increased levels of lactate dehydrogenase (LDH) in culture supernatants. Furthermore, we have found that the levels of cleaved poly (ADP-ribose) polymerase (PARP) and cleaved (activated) caspase-3 are increased upon treatment with TWEAK. TWEAK also induces oxidative stress in cultured myotubes. A general antioxidant, N-acetyl-L-cysteine (NAC), partially blocked TWEAK-induced cytotoxicity in cultured myotubes. Conclusions: Our results provide initial evidence that in addition to causing atrophy, TWEAK can also diminish skeletal muscle mass by inducing oxidative stress, which diminishes the survival of myofibers in catabolic conditions.
McMillan, Joseph Dekward IV, "TNF-like weak inducer of apoptosis (TWEAK) : not so weak after all." (2016). Electronic Theses and Dissertations. Paper 2617.