Investigation of the modulatory effects of fabomotizole and/or sertraline on cisplatin nephrotoxicity via in vivo and in vitro approaches: insights into the role of Sig-1R/ERK1/2 signaling in regulating mitochondrial dynamics and apoptotic cellular death.

Mitochondrial dynamics disruption and the proapoptotic proteins activation are reported to be the major protagonists of the pathological alterations in cisplatin-induced nephrotoxicity. This study assessed the impact of modulating Sig-1R activity by fabomotizole and/or sertraline on cisplatin nephrotoxicity focusing on the regulation of renal mitochondrial homeostasis and apoptotic cellular death. Four groups of rats received a single cisplatin injection, and were assigned to: cisplatin control, sertraline-treated, fabomotizole-treated, sertraline + fabomotizole-treated groups, along with a fifth normal control group. In parallel, HEK293 cells were used to evaluate the effects of the tested agents on renal cell viability. Elevated concentrations of sertraline reduced HEK293 cell viability. Additionally, sertraline maintained the noxious effect of cisplatin on mitochondrial homeostasis and renal apoptosis in rats. In contrast, fabomotizole improved cell viability in HEK293 cells exposed to cisplatin. It preserved the structural integrity of the renal tubular cells and suppressed plasma levels of NGAL, BUN and creatinine in cisplatin-intoxicated rats. Electron microscopy revealed that fabomotizole restored mitochondrial homeostasis, as shown by increased mitochondrial density. Mechanistically, fabomotizole downregulated the mitochondrial fission mediator Drp1 while upregulating the mitochondrial fusion mediator Mfn1; this was reflected on the mitochondrial function by reinstating renal ATP content. Furthermore, fabomotizole hindered ERK1/2 activation and reduced the proapoptotic proteins, Bax and Bak along with caspase 3 activity. As demonstrated by the Sig-1R antagonistic effect of sertraline, which notably negated fabomotizole's renoprotective potential, fabomotizole's capacity to preserve stable mitochondrial dynamics and hamper apoptosis following cisplatin nephrotoxicity may be ascribed to its Sig-1R activation-mediated ERK 1/2 inhibition.