Clinical impact of a change in antibiotics or the addition of glycopeptide antibiotics for persistent febrile neutropenia after autologous stem cell transplantation.

BACKGROUND: A change in empirical antibiotics or the addition of glycopeptide antibiotics is often applied in cases of persistent febrile neutropenia (FN) despite the administration of broad-spectrum antibiotics. However, the clinical benefit of these approaches remains unclear. METHODS: We conducted a retrospective study to evaluate the effectiveness of a change in antibiotics or the addition of glycopeptide antibiotics for persistent FN after autologous hematopoietic cell transplantation (auto-HCT). We retrospectively reviewed the records of 208 patients who received auto-HCT at our institution between 2007 and 2019. FN that lasted for 4 days or longer was defined as persistent FN. We compared the time to defervescence between patients whose initial antibiotics were changed and/or who additionally received glycopeptide antibiotics, and those without these antibiotic modifications. RESULTS: Among patients who fulfilled the criteria of persistent FN (n = 125), changes in antibiotics were not significantly associated with the time to defervescence in a multivariate analysis (hazard ratio [HR] 0.72, p = 0.27). On the other hand, the addition of glycopeptide antibiotics was paradoxically associated with a delay in defervescence (HR 0.56, p = 0.033). CONCLUSIONS: Although there may be differences in patient backgrounds, no significant differences were observed in either a univariate or multivariate analysis. Since neither a change in antibiotics nor the addition of glycopeptide antibiotics was associated with earlier defervescence in persistent FN after auto-HCT, routine antibiotic modifications might not be necessary in this setting.

Roquin-2 promotes oxidative stress-induced cell death by ubiquitination-dependent degradation of TAK1.

Reactive oxygen species (ROS) are highly reactive and their accumulation causes oxidative damage to cells. Cells maintain survival upon mild oxidative stress with anti-oxidative systems, such as the kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2-related factor 2 (Nrf2) system. On the other hand, upon severe oxidative stress, cells undergo regulated cell death, including apoptosis, for eliminating damaged cells. To execute efficient cell death, cells need to turn off the anti-oxidant systems, while triggering cell death. However, it remains unknown how cells orchestrate these two conflicting systems under excessive oxidative stress. Herein, we show that when cells are exposed to excessive oxidative damage, an E3 ubiquitin ligase Roquin-2 (also known as RC3H2) plays a key role in switching cell fate from survival to death by terminating activation of transforming growth factor-ß-activated kinase 1 (TAK1), a positive regulator for Nrf2 activation. Roquin-2 interacted with TAK1 via four cysteine residues in TAK1 (C96, C302, C486, and C500) that are susceptible to oxidative stress and participate in oligomer formation via disulfide bonds, promoting K48-linked polyubiquitination and degradation of TAK1. Nrf2 was inactivated upon lethal oxidative stress in wild-type mouse embryonic fibroblast (MEF) cells, whereas it sustained activation and conferred resistance to Roquin-2 deficient cells, which was reversed by pharmacological or genetic inhibition of TAK1. These data demonstrate that in response to excessive ROS exposure, Roquin-2 promotes ubiquitination and degradation of TAK1 to suppress Nrf2 activation, and thereby contributes to an efficient cell death, providing insight into the pathogenesis of oxidative stress-related diseases, including cancer.