Salmonella‑induced miR‑155 enhances necroptotic death in macrophage cells via targeting RIP1/3

Abstract

Salmonella enterica serovar Typhimurium (hereafter referred to as Salmonella), a virulent pathogen, is known to induce host-cell death. Using reverse transcription-quantitative polymerase chain reaction, a 28-fold increase of microRNA (miR)-155 expression in RAW 264.7 macrophages was observed following infection with Salmonella for 24 h. This miR-155 upregulation increased macrophage cell death by up to 40% in 48 h following infection. Western blot analysis revealed that receptor interacting protein 1 (RIP1) and 3 (RIP3) were increased at 18 h following miR-155 transfection to macrophages, similar to Salmonella infection. In addition, inhibition of RIP1 by pre-incubating macrophages with necrostatin-1, a RIP1 specific inhibitor, increased the viability of Salmonella-infected cells and miR-155-transfected cells by up to 20%. The cleavage of poly (adenosine diphosphate-ribose) polymerase-1 (PARP-1) was also enhanced by miR-155 induction upon Salmonella infection. Therefore, it was suggested that RIP1/3-induced necroptosis and PARP-1-mediated necrosis caused by miR-155 induction may represent distinct routes of programmed necrotic cell death of Salmonella-infected macrophages.

Host Cell Death Responses to Non-typhoidal Salmonella Infection

“…Other explorations of necroptosis in the context of S . Typhimurium infection involved the use of qRT-PCR techniques to assess the expression of micro RNAs (miRNAs) induced by infection in RAW264.7 cells (78). A highly upregulated miRNA, miR-155, mediated cytotoxicity levels similar to S .…”

“…A highly upregulated miRNA, miR-155, mediated cytotoxicity levels similar to S . Typhimurium-infected cells when transfected into RAW264.7s (78). Further in vitro transfections indicated that miR-155 induced RIPK1 and RIPK3 phosphorylation (indicative of necroptosis) by 18 h post-treatment, as well as cleavage of poly (ADP-ribose) polymerase-1 (PARP-1) in a similar manner to S .…”

“…Further in vitro transfections indicated that miR-155 induced RIPK1 and RIPK3 phosphorylation (indicative of necroptosis) by 18 h post-treatment, as well as cleavage of poly (ADP-ribose) polymerase-1 (PARP-1) in a similar manner to S . Typhimurium infection (78). Treatment with RIPK1 inhibitor necrostatin-1s partially rescued cell viability in miR-155 transfected cells, supporting a role for necroptosis in contributing to cytotoxicity (78).…”

“…Typhimurium infection (78). Treatment with RIPK1 inhibitor necrostatin-1s partially rescued cell viability in miR-155 transfected cells, supporting a role for necroptosis in contributing to cytotoxicity (78). The authors suggested that PARP-1 activation occurs downstream of RIPK1/RIPK3 activation, however existing work in TNF-stimulated L929 cells instead proposes that PARP-1 contributes to a separate programmed necrosis pathway (78, 79).…”

The diverse roles of RIP kinases in host-pathogen interactions

“…The resulting necroptotic cell death facilitates macrophage elimination, leading to compromised pathogen control. Alternatively, Ro et al [ 118 ] reported that microRNA (miR)-155 upregulation following S. Typhimurium infection drives necroptotic macrophage death. Transfection of miR-155 in vitro induces RIPK1 and RIPK3 activation and subsequent necroptosis, which is partly inhibited following Nec-1 treatment.…”