The Role and Mechanism of TRIM13 Regulation of TRAF6 Ubiquitination in the Synergy of Inflammatory Responses and Neurotoxicity Induced by METH and HIV- 1 Tat Protein in Astrocytes.

Methamphetamine (METH) abuse and HIV infection are major public health concerns worldwide. While both METH and HIV- 1 Tat proteins can induce neurotoxicity and synergistic effects on the nervous system, the mechanisms by which they act synergistically remain unclear. Our recent research shows that neuroinflammation plays an important role in neurotoxicity induced by METH and HIV- 1 Tat proteins, but the regulatory mechanism has not been clarified. Tripartite Motif Containing 13 (TRIM13) is a protein known to regulate the inflammatory response through ubiquitination of Tumor Necrosis Factor Receptor Associated Factor 6 (TRAF6). This study investigated the role of TRIM13 and TRAF6 in the inflammatory response of U- 87 MG cells induced by METH and HIV- 1 Tat proteins. U- 87 MG cells were treated with 2 mM METH and/or 100 nM HIV- 1 Tat protein. Western blot (WB), immunofluorescence (IF), and co-immunoprecipitation (Co-IP) experiments were employed to elucidate the role of TRIM13 and TRAF6. The results demonstrated that METH and HIV- 1 Tat protein could synergistically induce an inflammatory response in U- 87 MG cells. Furthermore, the knockdown of TRIM13 significantly enhanced this inflammatory response, while the inhibition of TRAF6 significantly weakened it. Additionally, the study revealed that TRIM13 could degrade TRAF6 via ubiquitination. In conclusion, this study suggests that TRIM13 regulates TRAF6 ubiquitination to dampen the inflammatory response of U- 87 MG cells induced by METH and HIV- 1 Tat proteins. These findings highlight TRIM13 and TRAF6 as potential targets for therapeutic intervention in the context of METH and HIV- 1 Tat protein-induced inflammatory responses and neurotoxic effects.