Abietic acid attenuates sepsis-induced lung injury by inhibiting nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway to inhibit M1 macrophage polarization

Lung injury is one of the leading causes of death in sepsis. Abietic acid (AA) has demonstrated anti-inflammatory and bacteriostatic properties. Herein, we established a mouse model of sepsis by cecal ligation and puncture, and intraperitoneally injected AA to treat. Lung injury was assessed by H&E staining and the inflammation in bronchoalveolar lavage fluid (BALF) were assessed by counting the number of inflammatory cells and detecting the content of inflammatory factors. Meanwhile, we also designed to study the effect of AA on lipopolysaccharide (LPS)-induced inflammatory response and macrophage marker gene expression in RAW264.7 cells in vitro. In this study, we found that AA inhibited LPS-induced secretion of inflammatory mediators (IL-1β, TNF-α, IL-6 and MIP-2), and decreased the expression of M1 macrophage e markers (CD16 and iNOS) and p-p65 protein, while increased the expression of M2 macrophage markers (CD206 and Arg-1) in RAW264.7 cells in vitro. In vivo, the therapy of AA not only rescued septic animals, but also attenuated lung injury in sepsis mice. Moreover, AA decreased the number of total cells, neutrophils and macrophages, the conceration of total protein, and the levels of inflammatory mediators in BALF of sepsis mice. Further, we found that AA inhibited M1 macrophage polarization and blocked nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway in BALF of sepsis mice. In conclusion, Abietic acid attenuates sepsis-induced lung injury, and its mechanism may be related to reducing inflammation by inhibiting NF-κB signaling to inhibit M1 macrophage polarization.     

Genetic deficiency of NADPH oxidase does not diminish,but rather enhances,LPS-induced acute inflammatory responses in vivo

Reactive oxygen species (ROS) and oxidative stress are thought to play a central role in the etiology of cell dysfunction and tissue damage in sepsis. However, there is limited and controversial evidence from in vivo studies that ROS mediate cell signaling processes that elicit acute inflammatory responses during sepsis. Because NADPH oxidase is one of the main cellular sources of ROS, we investigated the role of this enzyme in lipopolysaccharide (LPS)-induced acute inflammation in vivo, utilizing mice deficient in the gp91^phox or p47^phox subunits of NADPH oxidase. Age-and body weight-matched C57BL/6J wild-type (WT) and gp91^phox?/? and p47^phox?/? mice were injected ip with 50 μg LPS or saline vehicle and sacrificed at various time points up to 24 h. We found that LPS-induced acute inflammatory responses in serum and tissues were not significantly diminished in gp91^phox?/? and p47^phox?/? mice compared to WT mice. Rather, genetic deficiency of NADPH oxidase was associated with enhanced gene expression of inflammatory mediators and increased neutrophil recruitment to lung and heart. Furthermore, no protection from LPS-induced septic death was observed in either knockout strain. Our findings suggest that NADPH oxidase-mediated ROS production and cellular redox signaling do not promote, but instead limit, LPS-induced acute inflammatory responses in vivo.     

The critical role played by endotoxin-induced liver autophagy in the maintenance of lipid metabolism during sepsis

Macroautophagy/autophagy is a central mechanism by which cells maintain integrity and homeostasis, and endotoxin-induced autophagy plays important roles in innate immunity. Although TLR4 stimulation mediated by lipopolysaccharide (LPS) also upregulates autophagy in hepatocytes and liver, its physiological role remains elusive. The objective of this study was to determine the role of LPS-induced autophagy in the regulation of liver lipid metabolism. LPS treatment (5 mg/kg) increased autophagy, as detected by LC3 conversion and transmission electron microscopy (TEM) analysis in C57BL6 mouse livers. AC2F hepatocytes also showed increased autophagic flux after LPS treatment (1 μg/ml). To investigate the role of LPS-induced autophagy further, liver lipid metabolism changes in LPS-treated mice and fasted controls were compared. Interestingly, LPS-treated mice showed less lipid accumulation in liver than fasted mice despite increased fatty acid uptake and lipid synthesis-associated genes. In vitro analysis using AC2F hepatocytes demonstrated LPS-induced autophagy influenced the degradation of lipid droplets. Inhibition of LPS-induced autophagy using bafilomycin A₁ or Atg7 knockdown significantly increased lipid accumulation in AC2F hepatocytes. In addition, pretreatment with chloroquine aggravated LPS-induced lipid accumulation and inflammation in C57BL6 mouse livers. The physiological importance of autophagy was verified in LPS-treated young and aged rats. Autophagic response was diminished in LPS-treated aged rats and lipid metabolism was impaired during sepsis, indicating autophagy response is important for regulating lipid metabolism after endotoxin challenge. Our findings demonstrate endotoxin-induced autophagy is important for the regulation of lipid metabolism, and suggest that autophagy helps maintain lipid metabolism homeostasis during sepsis.     

Farnesyltransferase inhibitor improved survival following endotoxin challenge in mice

Endotoxemia plays an important role in the pathogenesis of sepsis and is accompanied by dysregulated apoptosis of immune and non-immune cells. Treatment with statins reduces mortality in rodent models of sepsis and endotoxemia. Inhibition of protein isoprenylation, including farnesylation, has been proposed as a mechanism to mediate the lipid-lowering-independent effects of statins. Nonetheless, the effects of the inhibition of isoprenylation have not yet been studied. To investigate the role of farnesylation, we evaluated the effects of farnesyltransferase inhibitor and statin on survival following lipopolysaccharide (LPS) challenge in mice. Both simvastatin (2 mg/kg BW) and FTI-277 (20 mg/kg BW) treatment improved survival by twofold after LPS injection, as compared with vehicle alone (p < 0.01). LPS-induced cleavage (activation) of caspase-3, an indicator of apoptotic change, and increased protein expression of proapoptotic molecules, Bax and Bim, and activation of c-Jun NH₂-terminal kinase (JNK/SAPK) in the liver and spleen were attenuated by both simvastatin and FTI-277. These results demonstrate that farnesyltransferase inhibitor as well as statin significantly reduced LPS-induced mortality in mice. Our findings also suggest that inhibition of protein farnesylation may contribute to the lipid-lowering-independent protective effects of statins in endotoxemia, and that protein farnesylation may play a role in LPS-induced stress response, including JNK/SAPK activation, and apoptotic change. Our data argue that farnesyltransferase may be a potential molecular target for treating patients with endotoxemia.     

Interleukin-35 Inhibits Endothelial Cell Activation by Suppressing MAPK-AP-1 Pathway

Vascular response is an essential pathological mechanism underlying various inflammatory diseases. This study determines whether IL-35, a novel responsive anti-inflammatory cytokine, inhibits vascular response in acute inflammation. Using a mouse model of LPS-induced acute inflammation and plasma samples from sepsis patients, we found that IL-35 was induced in the plasma of mice after LPS injection as well as in the plasma of sepsis patients. In addition, IL-35 decreased LPS-induced proinflammatory cytokines and chemokines in the plasma of mice. Furthermore, IL-35 inhibited leukocyte adhesion to the endothelium in the vessels of lung and cremaster muscle and decreased the numbers of inflammatory cells in bronchoalveolar lavage fluid. Mechanistically, IL-35 inhibited the LPS-induced up-regulation of endothelial cell (EC) adhesion molecule VCAM-1 through IL-35 receptors gp130 and IL-12Rβ2 via inhibition of the MAPK-activator protein-1 (AP-1) signaling pathway. We also found that IL-27, which shares the EBI3 subunit with IL-35, promoted LPS-induced VCAM-1 in human aortic ECs and that EBI3-deficient mice had similar vascular response to LPS when compared with that of WT mice. These results demonstrated for the first time that inflammation-induced IL-35 inhibits LPS-induced EC activation by suppressing MAPK-AP1-mediated VCAM-1 expression and attenuates LPS-induced secretion of proinflammatory cytokines/chemokines. Our results provide insight into the control of vascular inflammation by IL-35 and suggest that IL-35 is an attractive novel therapeutic reagent for sepsis and cardiovascular diseases.     

Role of CD69 in acute lung injury

AimsCD69 is an early activation marker in lymphocytes and an important signal transmitter in inflammatory processes. However, its role in acute lung injury (ALI) is still unknown. We used a lipopolysaccharide (LPS)-induced mouse model of ALI to study the role of macrophage-surface CD69 in this condition.Main methodsWe investigated bronchoalveolar lavage fluid (BALF) cell subpopulations, myeloperoxidase levels in lung homogenates, lung pathology, and lung oedema in CD69-deficient (CD69^?/?) mice 24 h after LPS instillation. We also determined cytokine/chemokine expression levels in BALF and macrophage culture supernatant from CD69^?/? and wild type (WT) mice. Also, we investigated CD69, keratinocyte-derived chemokine (KC) and macrophage inflammatory protein (MIP)-2 localization in the lungs after LPS administration. Furthermore, we examined the effect of anti-CD69 antibody on LPS-induced cytokine/chemokine release from cultured macrophages.Key findingsOur study shows that intratracheal instillation of LPS-induced neutrophilic infiltration, histopathological changes, myeloperoxidase positivity, and oedema in the lung to a lower degree in CD69^?/? mice than in WT mice. The immunoreactivities for CD69, KC and MIP2 were induced in the lung of WT mice instilled with LPS and were predominantly localized to the macrophages. Moreover, the cytokine/chemokine expression profile between the two genotypes of cultured macrophages in response to LPS was similar to that observed in the BALF. In addition, anti-CD69 antibody inhibited the LPS-induced cytokine/chemokine expression.SignificanceThese results suggest that CD69 on macrophages plays a crucial role in the progression of LPS-induced ALI and may be a potentially useful target in the therapy for ALI.     

Potential role of Hedgehog signaling and microRNA-29 in liver fibrosis of IKKβ-deficient mouse

Recent studies have reported that NF-κB mediated down-regulation of miRNA-29 and lower expression of miRNA-29 promoted the deposition of collagens in fibrotic liver. Our previous research demonstrated that the increased Hedgehog (Hh) signaling, a key regulator for hepatic fibrogenesis, induced the severe hepatic fibrosis in the livers with impaired NF-κB signaling. These findings led us to investigate the effect of Hh and miRNA-29 on the hepatic fibrosis under dysregulated NF-κB signaling. In this study, we used IKKβ^F/F and IKKβ-deficient IKKβ^ΔHEP mouse model with a defective NF-κB signaling pathway, and assessed the expression of the miRNA-29 family (miRNA-29a, miRNA-29b, and miRNA-29c), Hh, and proliferation of MF-HSCs in liver from IKKβ^F/F mice and IKKβ^ΔHEP mice both before and after MCDE treatment. The activation of NF-κB was significantly increased in MCDE diet-fed IKKβ^F/F mice compared to IKKβ^ΔHEP mice. Expression of miRNA-29 family was greater in MCDE diet-fed IKKβ^ΔHEP mice than IKKβ^F/F mice, demonstrating that the impaired NF-κB pathway was unable to suppress the expression of miRNA-29s after injury. However, expression of the Hh signaling pathway was greatly enhanced, and activation of Hh promoted the accumulation of MF-HSCs with impaired NF-κB, eventually increasing fibrogenesis in the damaged liver of IKKβ^ΔHEP mice. Therefore, these results demonstrated that Hh signaling regulates the proliferation of MF-HSCs irrespective of the action of miRNA-29, eventually contributing hepatic fibrosis, when the NF-κB pathway is disrupted.     

Adenosine 5′-monophosphate ameliorates D-galactosamine/lipopolysaccharide-induced liver injury through an adenosine receptor-independent mechanism in mice

D-galactosamine (GalN)/lipopolysaccharide (LPS)-induced lethality and acute liver failure is dependent on endogenously produced inflammatory cytokines. Adenosine has been proven to be a central role in the regulation of inflammatory response. It is not entirely clear that which adenosine action is actually crucial to limiting inflammatory tissue destruction. Here we showed that GalN/LPS challenge elevated hepatic adenosine and induced lethality in adenosine receptor-deficient mice with equal efficiency as wild-type mice. In GalN/LPS-treated mice, pretreatment with adenosine 5′-monophosphate (5′-AMP) significantly elevated hepatic adenosine level and reduced mortality through decreasing cytokine and chemokine production. In RAW264.7 cells, 5′-AMP treatment inhibited the production of inflammatory cytokines, which is not mediated through adenosine receptors. 5′-AMP failed to attenuate LPS-induced nuclear factor-κB (NF-κB) p65 nuclear translocation, but reduced LPS-induced recruitment of NF-κB p65 to inflammatory gene promoters and decreased LPS-induced enrichment of H3K4 dimethylation at the tumor necrosis factor-α (TNF-α) promoter, which was involved in 5′-AMP-induced elevation of cellular adenosine and a decline of methylation potential. In vitro biochemical analysis revealed that adenosine directly attenuated recruitment of NF-κB to the TNF-α and interleukin-6 promoters. Our findings demonstrate that 5′-AMP-inhibiting inflammatory response is not mediated by adenosine receptors and it may represent a potential protective agent for amelioration of LPS-induced liver injury.     

Mas-related G protein-coupled receptor D participates in inflammatory pain by promoting NF-κB activation through interaction with TAK1 and IKK complex

Mas-related G protein-coupled receptor D (MrgprD) is mainly expressed in small-diameter sensory neurons of the dorsal root ganglion (DRG). Results from previous studies suggest that MrgprD participates in mechanical hyperalgesia and nerve injury-induced neuropathic pain. However, it remains elusive whether and how MrgprD is involved in inflammatory pain. Here, we used a mouse model of chronic inflammatory pain established by intraperitoneal administration of lipopolysaccharide (LPS). The LPS injection induced an evident peripheral neuroinflammation and mechanical hyperalgesia in the mice and increased MrgprD expression in the DRG. The LPS administration also augmented the proportion of MrgprD-expressing neurons in the lumbar 4 DRG. Behaviorally, the LPS-induced hypersensitivities to mechanical and cold stimuli, but not to a heat stimulus, were substantially attenuated in Mrgprd-knockout mice compared with wildtype littermates. Mrgprd deletion in DRGs suppressed the LPS-triggered activation of the NF-κB signaling pathway and attenuated LPS-induced up-regulation of pro-inflammatory factors. Moreover, ectopic overexpression of MrgprD in HEK293 cells stably expressing mouse toll-like receptor 4 (TLR4) markedly promoted the LPS-induced NF-κB activation and enhanced NF-κB's DNA-binding activity. Furthermore, MrgprD physically interacted with TGF-β-activated kinase 1 (TAK1) and I-kappa-B-kinase (IKK) complexes, but not with mitogen-activated protein kinases (MAPKs) in mouse DRGs. In macrophage-like RAW 264.7 cells, MrgprD also interacted with TAK1 and IKK complex, and the treatment of MrgprD agonist elicited the activation of NF-κB signaling, but not of mitogen-activated protein kinases (MAPKs) signaling pathway. Our findings indicate that MrgprD facilitates the development of LPS-triggered persistent inflammatory hyperalgesia by promoting canonical NF-κB activation, highlighting the important roles of MrgprD in NF-κB-mediated inflammation and chronic pain.     

Inhibition of c-Jun N-terminal kinase increases apoE expression in vitro and in vivo

Apolipoprotein E (apoE), a ligand for the low-density lipoprotein receptor family, has been implicated in modulating glial inflammatory responses and the risk of neurodegeneration associated with Alzheimer’s disease. Glial cells activated by lipopolysaccharide (LPS) have decreased apoE levels and we recently showed that apoE itself can modulate the inflammatory response by reducing c-Jun N-terminal kinase (JNK) activation. Reduced JNK phosphorylation is vital to overcome the LPS-induced decrease in apoE expression, suggesting that JNK inhibition may be an effective way to increase apoE protein and protract its anti-inflammatory properties. This study investigates the impact of JNK inhibition on apoE production using two JNK inhibitors. Our work in primary glia and in vivo in mice injected with JNK inhibitor demonstrates that inhibition of JNK may be an effective way to increase apoE expression.     

Soluble Factors from Lactobacillus reuteri CRL1098 Have Anti-Inflammatory Effects in Acute Lung Injury Induced by Lipopolysaccharide in Mice

We have previously demonstrated that Lactobacillus reuteri CRL1098 soluble factors were able to reduce TNF-α production by human peripheral blood mononuclear cells. The aims of this study were to determine whether L. reuteri CRL1098 soluble factors were able to modulate in vitro the inflammatory response triggered by LPS in murine macrophages, to gain insight into the molecular mechanisms involved in the immunoregulatory effect, and to evaluate in vivo its capacity to exert anti-inflammatory actions in acute lung injury induced by LPS in mice. In vitro assays demonstrated that L. reuteri CRL1098 soluble factors significantly reduced the production of pro-inflammatory mediators (NO, COX-2, and Hsp70) and pro-inflammatory cytokines (TNF-α, and IL-6) caused by the stimulation of macrophages with LPS. NF-kB and PI3K inhibition by L. reuteri CRL1098 soluble factors contributed to these inhibitory effects. Inhibition of PI3K/Akt pathway and the diminished expression of CD14 could be involved in the immunoregulatory effect. In addition, our in vivo data proved that the LPS-induced secretion of the pro-inflammatory cytokines, inflammatory cells recruitment to the airways and inflammatory lung tissue damage were reduced in L. reuteri CRL1098 soluble factors treated mice, providing a new way to reduce excessive pulmonary inflammation.     

Heterotrimeric Gαi proteins are regulated by lipopolysaccharide and are anti-inflammatory in endotoxemia and polymicrobial sepsis

Previous studies have implicated a role of heterotrimeric Gα_i proteins in lipopolysaccharide (LPS)-induced inflammatory responses. We hypothesized that Toll-like receptor (TLR) signaling regulates Gα_i proteins, which are anti-inflammatory in endotoxemia and polymicrobial sepsis. RAW 264.7 cells were stimulated with LPS and the Gα_i-GTP protein complex was immunoprecipitated with a Gα_i protein activation assay. In subsequent in vivo studies, the Gα_i protein inhibitor pertussis toxin (PTx) or G_i protein agonist mastoparan (MP-7) were administrated prior to endotoxemia. LPS-induced pro-inflammatory cytokines and mortality were determined. To examine the role of Gα_i2 in sepsis, Gα_i2 (−/−) and wildtype (WT) mice were subjected to cecal ligation and puncture (CLP) and monitored every 24 h for 120 h. Other mice were sacrificed 24 h after CLP. Peritoneal fluid, blood, and tissue samples were collected. Plasma pro-inflammatory cytokine production, bacterial load in peritoneal fluid, blood and lung tissue, myeloperoxidase (MPO) activity in lung and liver and different immune cell populations in spleen were studied. We found that Gα_i proteins are rapidly activated by LPS followed by rapid inactivation. These studies provide the first direct evidence that Gα_i proteins are modulated by TLR signaling. In following studies, PTx augmented LPS-induced plasma TNFα, IL-6, whereas MP-7 suppressed LPS-induced TNFα and decreased LPS-induced mortality. In sepsis studies, the survival rate post-CLP was significantly decreased in the Gα_i2 (−/−) mice compared to WT mice. CLP-induced plasma TNFα, IL-6, bacterial load in peritoneal fluid, blood and lung tissue and lung and liver MPO activity were significantly increased in Gα_i2 (−/−) compared to WT mice. Gα_i2 (−/−) mice also exhibited increased Th1 and Th2 responses compared to WT mice. Taken together, Gα_i proteins are activated by LPS and negatively regulate endotoxemia and sepsis. Understanding the role of Gα_i2 protein in regulation of the inflammatory response in sepsis may provide novel targets for treatment of sepsis.     

Yohimbine Enhances Protection of Berberine against LPS-Induced Mouse Lethality through Multiple Mechanisms

Sepsis remains a major cause of mortality in intensive care units, better therapies are urgently needed. Gram-negative bacterial lipopolysaccharide (LPS) is an important trigger of sepsis. We have demonstrated that berberine (Ber) protects against lethality induced by LPS, which is enhanced by yohimbine (Y) pretreatment, and Ber combined with Y also improves survival in septic mice. However, the precise mechanisms by which Y enhances protection of Ber against LPS - induced lethality remain unclear. The present study confirmed that simultaneously administered Y also enhanced protection of Ber against LPS-induced lethality. Ber or/and Y attenuated liver injury, but not renal injury in LPS-challenged mice. Ber or/and Y all inhibited LPS-stimulated IκBα, JNK and ERK phosphorylation, NF-κB activation as well as TNF-α production. Ber also increased IL-10 production in LPS-challenged mice, which was enhanced by Y. Furthermore, Ber or/and Y all suppressed LPS-induced IRF3, TyK2 and STAT1 phosphorylation, as well as IFN-β and IP-10 mRNA expression in spleen of mice at 1 h after LPS challenge. Especially, Y enhanced the inhibitory effect of Ber on LPS-induced IP-10 mRNA expression. In vitro experiments further demonstrated that Y significantly enhanced the inhibitory effect of Ber on TNF-α production in LPS-treated peritoneal macrophages, Ber combined with Y promoted LPS-induced IL-10 production and LPS-stimulated IκBα, JNK, ERK and IRF3 phosphorylation and NF-κB activation were also suppressed by Ber or/and Y pretreatment in peritoneal macrophages. Taken together, these results demonstrate that Y enhances the protection of Ber against LPS-induced lethality in mice via attenuating liver injury, upregulating IL-10 production and suppressing IκBα, JNK, ERK and IRF3 phosphorylation. Ber combined with Y may be an effective immunomodulator agent for the prevention of sepsis.     

Orally Administered Melatonin Prevents Lipopolysaccharide-Induced Neural Tube Defects in Mice

Lipopolysaccharide (LPS) has been associated with adverse pregnant outcomes, including fetal demise, intra-uterine growth restriction (IUGR), neural tube defects (NTDs) and preterm delivery in rodent animals. Previous studies demonstrated that melatonin protected against LPS-induced fetal demise, IUGR and preterm delivery. The aim of the present study was to investigate the effects of melatonin on LPS-induced NTDs. All pregnant mice except controls were intraperitoneally injected with LPS (25 µg/kg) daily from gestational day (GD)8 to GD12. Some pregnant mice were orally administered with melatonin (MT, 50 mg/kg) before each LPS injection. A five-day LPS injection resulted in 27.5% of fetuses with anencephaly, exencephaly or encephalomeningocele. Additional experiment showed that maternal LPS exposure significantly down-regulated placental proton-coupled folate transporter (pcft) and disturbed folate transport from maternal circulation through the placentas into the fetus. Interestingly, melatonin significantly attenuated LPS-induced down-regulation of placental pcft. Moreover, melatonin markedly improved the transport of folate from maternal circulation through the placentas into the fetus. Correspondingly, orally administered melatonin reduced the incidence of LPS-induced anencephaly, exencephaly or encephalomeningocele. Taken together, these results suggest that orally administered melatonin prevents LPS-induced NTDs through alleviating LPS-induced disturbance of folate transport from maternal circulation through the placenta into the fetus.     

High Density Lipoprotein Protects against Polymicrobe-induced Sepsis in Mice

HDL has been considered to be a protective factor in sepsis; however, most contributing studies were conducted using the endotoxic animal model, and evidence from clinically relevant septic animal models remains limited and controversial. Furthermore, little is known about the roles of HDL in sepsis other than LPS neutralization. In this study, we employed cecal ligation and puncture (CLP), a clinically relevant septic animal model, and utilized apoA-I knock-out (KO) and transgenic mice to elucidate the roles of HDL in sepsis. ApoA-I-KO mice were more susceptible to CLP-induced septic death as shown by the 47.1% survival of apoA-I-KO mice versus the 76.7% survival of C57BL/6J (B6) mice (p = 0.038). ApoA-I-KO mice had exacerbated inflammatory cytokine production during sepsis compared with B6 mice. Further study indicated that serum from apoA-I-KO mice displayed less capacity for LPS neutralization compared with serum from B6 mice. In addition, apoA-I-KO mice had less LPS clearance, reduced corticosterone generation, and impaired leukocyte recruitment in sepsis. In contrast to apoA-I-KO mice, apoA-I transgenic mice were moderately resistant to CLP-induced septic death compared with B6 mice. In conclusion, our findings reveal multiple protective roles of HDL in CLP-induced sepsis. In addition to its well established role in neutralization of LPS, HDL exerts its protection against sepsis through promoting LPS clearance and modulating corticosterone production and leukocyte recruitment. Our study supports efforts to raise HDL levels as a therapeutic approach for sepsis.     

Divergent results induced by different types of septic shock in transglutaminase 2 knockout mice

Acute sepsis can be induced by cytokines such as TNF-α and biological products such as LPS. All of these agents cause systemic inflammation, which is characterized by hemodynamic shock and liver toxicity. However, the outcomes of different septic shock models were totally opposite in transglutaminase 2 knockout (TGase 2^?/?) mice. The aim of our study was to clarify the role of TGase 2 in liver injury. Therefore, we explored the role of TGase 2 in liver damage using two different stress models: LPS-induced endotoxic shock and TNF-α/actinomycin D (ActD)-induced sepsis. TNF-α-dependent septic shock resulted in increased liver damage in TGase 2^?/? mice compared with wild-type (WT) mice, and was accompanied by increased levels of caspase 3 and cathepsin D (CTSD) in the damaged liver. Conversely, LPS-induced septic shock resulted in ablation of inflammatory endotoxic shock in TGase 2^?/? mice and decreased liver injury. We found that TGase 2 protected liver tissue from TNF-α-dependent septic shock by reducing the expression of caspase 3 and CTSD. However, TGase 2 differently participated in increased the hemodynamic shock in LPS-induced septic shock through macrophage activation rather than protecting direct liver damage. Therefore, these findings demonstrate that septic shock caused by different agents may induce different results in TGase 2^?/? mice depending on the primary target organs affected.