Human Bax ELISA Kit

Many stresses induce the accumulation of unfolded and misfolded proteins in the endoplasmic reticulum, a phenomenon known as ER stress. In response to ER stress, cells initiate a protective response, known as unfolded protein response (UPR), to maintain cellular homeostasis. The UPR sensor, inositol-requiring enzyme 1 (IRE1), catalyzes the cytoplasmic splicing of bZIP transcription factor-encoding mRNAs to activate the UPR signaling pathway. Recently, we reported that pretreatment of Arabidopsis thaliana plants with tunicamycin, an ER stress inducer, increased their susceptibility to bacterial pathogens; on the other hand, IRE1 deficient mutants were susceptible to Pseudomonas syringae pv. maculicola (Psm) and failed to induce salicylic acid (SA)-mediated systemic acquired resistance. However, the functional relationship of IRE1 with the pathogen and TM treatment remains unknown. In the present study, we showed that bacterial pathogen-associated molecular patterns (PAMPs) induced IRE1 expression; however, PAMP-triggered immunity (PTI) response such as callose deposition, PR1 protein accumulation, or Pst DC3000 hrcC growth was not altered in ire1 mutants. We observed that IRE1 enhanced plant immunity against the bacterial pathogen P. syringae pv. tomato DC3000 (Pst DC3000) under ER stress. Moreover, TM-pretreated ire1 mutants were more susceptible to the avirulent strain Pst DC3000 (AvrRpt2) and showed greater cell death than wild-type plants during effector-triggered immunity (ETI). Additionally, Pst DC3000 (AvrRpt2)-mediated RIN4 degradation was reduced in ire1 mutants under TM-induced ER stress. Collectively, our results reveal that IRE1 plays a pivotal role in the immune signaling pathway to activate plant immunity against virulent and avirulent bacterial strains under ER stress.

Sepsis is caused by microbial infection with high mortality worldwide, and characterized by multiple organ dysfunction and systemic inflammatory response. Previous study shows that miR-181a level is increased during sepsis; however, the mechanism is still unknown. Therefore, to identify the role of miR-181a, lipopolysaccharide (LPS) was used to stimulate mouse peritoneal macrophages. The expressions of miR-181a and SIRT1 were identified by QRT-PCR, the levels of SIRT1, Nrf2, p-P65, Bcl-2 and Bax were detected by western blotting, the inflammatory cytokines TNF-alpha, IL-6 and IL-1 beta were detected by ELISA, and the apoptosis was measured by flow cytometry. Bioinformatics and dual luciferase assay were used to unveil the binding sites and the targeted regulatory relationship of miR-181a and SIRT1. LPS induced the upregulation of miR-181a, downregulation of SIRT1 and a strong inflammatory response. In addition, LPS stimulation inhibited the expression of Nrf2 and activated the NF-kappa B pathway. Moreover, the inhibition of miR-181a attenuated inflammatory response and apoptosis during LPS stimulation, which was implemented by up-regulating the expression of its target SIRT1. More fully, downregulation of SIRT1 by short hairpin interference resulted in a decreased expression of Nrf2, increased expression of p-P65 and proinflammatory cytokines, and intensive apoptosis. Downregulation of miR-181a could promote the expression of its target SIRT1, and then, attenuate inflammatory response and apoptosis via Nrf2 and NF-kappa B signaling pathways during LPS treatment. miR-181a can be a potential target of controlling the inflammatory response during sepsis and has important clinical significance for the treatment and rehabilitation of septic patients.