As with knockout of in mice, administration of MCC950 at +2, +12, +24, and +48?h after CLP also increased animal survival and decreased tissue injury, as confirmed by histology (Fig

As with knockout of in mice, administration of MCC950 at +2, +12, +24, and +48?h after CLP also increased animal survival and decreased tissue injury, as confirmed by histology (Fig.?3B) and enzyme assay (Fig.?3C) in and mice. WT mice within 8 d of CLP (Fig.?1A). Histological analysis revealed more pronounced damage in multiple organs FMK (e.g., liver, lung, kidney, heart, pancreas, brain, and small intestine) of the and mice compared with age- and sex-matched control mice (Fig.?1B). Biochemical measurement of tissue enzymes also exhibited a greater elevation of liver (e.g., GPT/ALT [glutamic pyruvic transaminase, soluble]), heart (e.g., TNNI [troponin I]), kidney (e.g., creatinine), and pancreas (e.g., AMY2 [amylase]) enzymes in the and mice (Fig.?1C). Similarly, serum MPO (myeloperoxidase) and LDH (lactate dehydrogenase) activities were remarkably higher in and mice than in WT mice (Fig.?1C), suggesting that sepsis-induced tissue injury is more significant in the and mice. Open in a separate window Figure 1. mice are more sensitive to polymicrobial sepsis due to impaired dopamine production. (A) Survival after moderate CLP in wild-type (WT), mice with or without pramipexole (PRA; 1?mg/kg/i.p. at 2, 12, 24, and 48?h after CLP) treatment (n=20 mice/group; *, 0.05). (B to H) In parallel, tissue H&E staining (B), serum enzyme activity (C), ATP levels (D), CASP3 activity in neurons (E), bacterial loads (F), dopamine concentrations (G), and the indicated gene mRNA in neurons (H) were assayed (n = 3 to 5 5 mice/group; *, 0.05 versus WT group; # vs. the group without PRA). Previous studies have suggested that loss of PINK1 or PARK2 results in a mitophagy deficiency-associated decrease of ATP synthesis and an increase of apoptosis in multiple cells, including neurons.6,10,11 Consistently, the tissue levels of ATP were significantly reduced FMK in brains and livers (Fig.?1D) and CASP3/caspase-3 activity (an apoptosis marker) were increased in brain tissue neurons (Fig.?1E) from and mice after CLP. The PINK1-PARK2 pathway also plays a role in xenophagy,12 a selective autophagic pathway that delivers intracellular bacteria for degradation in lysosomes. However, the number of colony-forming units from blood and peritoneal lavage after CLP did not differ between and mice showed a significantly larger reduction in central (brain) and peripheral (serum) dopamine levels after CLP (Fig.?1G). The gene expression of the enzymes (e.g., [phenylalanine hydroxylase], [tyrosine hydroxylase], and [dopa decarboxylase]) in the dopamine biosynthetic pathway did not significantly change in brain tissue neurons from and mice after CLP (Fig.?1H). These findings suggest that decreases in neuron survival (but not in impaired dopamine biosynthesis) contribute to loss of dopamine production in and mice. To determine whether the reduced dopamine levels contribute to septic death, we supplemented (intraperitoneally) the septic mice with pramipexole (PRA; a Food and Drug Administration-approved dopamine agonist for treating PD patients13) at +2, +12, +24, and +48?h after CLP. Remarkably, administration of PRA restored both brain and serum dopamine levels in septic and mice (Fig.?1G) and cocurrently increased their survival rates (Fig.?1A). Consistently, PRA also conferred protection against tissue injury, as determined by tissue histology (Fig.?1B) and enzyme release (Fig.?1C), although it did not affect tissue bacterial loads in septic and mice (Fig.?1F). Thus, these findings suggest that the reduced circulating dopamine levels contribute to the exacerbated septic lethality in animals that are defective in the PINK1 and PARK2 pathways. HMGB1 is a late mediator of septic death in pink1?/? and park2?/? mice The pathogenesis of lethal sepsis is partly FMK attributable to a dysregulated inflammatory response, as manifested by the overproduction of proinflammatory mediators. We next compared the circulating levels of inflammatory mediators between mice were higher than those in the WT mice FMK over a wide time ELF-1 period (6 to 48?h after CLP, Fig.?2A). However, treatment with PRA only markedly decreased the circulating levels of IL1B and HMGB1 (but not TNF, IL6, and CIRBP) in the septic and mice (Fig.?2A), suggesting that dopamine may specifically modulate the release of inflammasome-dependent cytokines during experimental sepsis. Open in a separate window Figure 2. HMGB1 is a late mediator of septic death in and mice. (A) Time course of serum proinflammatory mediator levels in CLP-induced wild-type (WT), mice with or without pramipexole (PRA; 1?mg/kg/i.p. at 2, 12, 24, and 48?h after CLP) treatment (n = 3 to 5 5 mice/group; *, 0.05 versus the group without PRA). (B) Survival FMK after moderate CLP in and mice with or without IgG (10?mg/kg/i.p. at +12, +24, and +48?h after CLP), HMGB1-neutralizing antibody (HMG1 Ab; 10?mg/kg/i.p. at +12, +24, and +48?h after CLP), and glycyrrhizin (Glz; 10?mg/kg/i.p. at +12, +24, and +48?h after CLP) (n = 10 mice/group;.