Hemorrhagic shock induces immune dysfunction via mesenteric lymph return, leading to systemic inflammatory response and multiple organ dysfunction. Dendritic cells (DCs) play a pivotal role in immune response following hemorrhagic shock. Therefore, identifying regulatory targets within DCs is essential for understanding hemorrhagic shock-induced immune dysfunction. Endoplasmic reticulum autophagy (ER-phagy), a selective form of autophagy, is critical for DC function. Here, we investigated the role of tumor necrosis factor-α-induced protein-8-like 2 (TIPE2), a protein known to regulate autophagy, in modulating DC ER-phagy after hemorrhagic shock. We analyzed the function and ER-phagy in splenic DCs from wild-type (WT) mice following hemorrhagic shock in vivo and DCs stimulated with post-hemorrhagic shock mesenteric lymph (PHSML) in vitro. Our results showed an increased number of autophagosomes containing endoplasmic reticulum (ER) structures, with significantly enhanced colocalization between ER and autophagosomes in DCs during hemorrhagic shock. The proliferation of CD4+ T cells co-cultured with DCs was weakened, and the expression of surface molecules on the DCs was significantly increased after stimulation with PHSML. Subsequently, WT, TIPE2-/- and TIPE2+/+ mice were used to further analyze the correlation between TIPE2 and ER-phagy in the context of hemorrhagic shock. The results demonstrated that under hemorrhagic shock conditions, TIPE2-/- mice exhibited a significantly reduced LC3-II/I ratio and elevated SEC61B expression in the spleen tissue compared to WT mice, suggesting a diminished level of ER-phagy. Conversely, TIPE2+/+ mice showed the opposite changes. Following stimulation with PHSML, the findings revealed a marked increase in the colocalization between ER and autophagosomes and a significant inhibition of DC function compared to the control group. Additionally, the deletion of TIPE2 weakened ER-phagy and decreased the inhibitory effect on DC function. In contrast, the overexpression of TIPE2 further enhanced ER-phagy and intensified the inhibition of DC function. In addition, TIPE2 is involved in the regulation of the non-classical ER-phagy receptor tripartite motif 13 (TRIM13) expression. These results suggest that ER-phagy is enhanced in DCs after hemorrhagic shock and that TIPE2 may regulate ER-phagy and DC function via TRIM13. This research provides a theoretical basis for future clinical therapeutic strategies targeting the regulation of ER-phagy to improve the function of DCs.
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