Integrative epigenetic analysis reveals AP-1 promotes activation of tumor-infiltrating regulatory T cells in HCC.

Regulatory T (Treg) cells that infiltrate human tumors exhibit stronger immunosuppressive activity compared to peripheral blood Treg cells (PBTRs), thus hindering the induction of effective antitumor immunity. Previous transcriptome studies have identified a set of genes that are conserved in tumor-infiltrating Treg cells (TITRs). However, epigenetic profiles of TITRs have not yet been completely deciphered. Here, we employed ATAC-seq and CUT&Tag assays to integrate transcriptome profiles and identify functional regulatory elements in TITRs. We observed a global difference in chromatin accessibility and enhancer landscapes between TITRs and PBTRs. We identified two types of active enhancer formation in TITRs. The H3K4me1-predetermined enhancers are poised to be activated in response to tumor microenvironmental stimuli. We found that AP-1 family motifs are enriched at the enhancer regions of TITRs. Finally, we validated that c-Jun binds at regulatory regions to regulate signature genes of TITRs and AP-1 is required for Treg cells activation in vitro. High c-Jun expression is correlated with poor survival in human HCC. Overall, our results provide insights into the mechanism of AP-1-mediated activation of TITRs and can hopefully be used to develop new therapeutic strategies targeting TITRs in liver cancer treatment.

Anti-mesothelin CAR-T immunotherapy in patients with ovarian cancer.

Recently, chimeric antigen receptor T cell (CAR-T) therapy has received increasing attention as an adoptive cellular immunotherapy that targets tumors. However, numerous challenges remain for the effective use of CAR-T to treat solid tumors, including ovarian cancer, which is an aggressive and metastatic cancer with a poor therapeutic response. We screened for an effective anti-MSLN single-chain Fv antibody with comparable binding activity and non-off-target properties using human phage display library. A second-generation of anti-MSLN CAR was designed and generated. We demonstrated the efficacy of our anti-MSLN CAR-T cells for ovarian cancer treatment in an in vitro experiment to kill ovarian tumor cell lines. The anti-MSLN CAR-T cells impeded MSLN-positive tumor growth concomitant with a significant increase in cytokine levels compared with the control. Then, we demonstrated the efficacy of anti-MSLN CAR-T cells in an in vivo experiment against ovarian cancer cell-derived xenografts. Furthermore, we herein report three cases with ovarian cancer who were treated with autologous anti-MSLN CAR-T cells and evaluate the safety and effectiveness of adoptive cell therapy. In this investigator-initiated clinical trials, no patients experienced cytokine release syndrome or neurological symptoms over 2 grads. Disease stabilized in two patients, with progression-free survival times of 5.8 and 4.6 months. Transient CAR expression was detected in patient blood after infusion each time. The tumor partially subsided, and the patient's condition was relieved. In conclusion, this work proves the efficacy of the anti-MSLN CAR-T treatment strategy in ovarian cancer and provides preliminary data for the development of further clinical trials.

Clinical Features of Recurrence After Hepatic Resection for Early-Stage Hepatocellular Carcinoma and Long-Term Survival Outcomes of Patients with Recurrence: A Multi-institutional Analysis.

BACKGROUND: A potentially curative hepatic resection is the optimal treatment for hepatocellular carcinoma (HCC), but most HCCs, even at an early stage, eventually recur after resection. This study investigates clinical features of initial recurrence and long-term prognosis of patients with recurrence after curative resection for early-stage HCC. PATIENTS AND METHODS: From a multicenter database, patients who underwent curative hepatic resection for early-stage HCC [Barcelona Clinic Liver Cancer (BCLC) stage 0/A] were extracted. Time to initial recurrence, patterns of initial recurrence, and treatment modalities for recurrent tumors were investigated. Univariate and multivariate analysis were used to identify independent risks associated with postoperative recurrence, as well as post-recurrence survival (PRS) for patients with recurrence. RESULTS: Among 1424 patients, 679 (47.7%) developed recurrence at a median follow-up of 54.8 months, including 408 (60.1%) early recurrence (≤ 2 years after surgery) and 271 (39.9%) late recurrence (> 2 years). Independent risks of postoperative recurrence included cirrhosis, preoperative alpha-fetoprotein level > 400 ug/L, tumor size > 5 cm, multiple tumors, satellites, microvascular invasion, and intraoperative blood transfusion. Multivariate analysis revealed that receiving irregular recurrence surveillance, initial tumor beyond Milan criteria, early recurrence, BCLC stage B/C of the recurrent tumor, and noncurative treatments were independently associated with poorer PRS. CONCLUSIONS: Nearly half of patients with early-stage HCC experienced recurrence after resection. Understanding recurrence risks may help identify patients at high risk of recurrence who may benefit from future adjuvant therapies. Meaningful survival even after recurrence can still be achieved by postoperative regular surveillance and curative treatment.

Association of Preoperative Body Mass Index with Surgical Textbook Outcomes Following Hepatectomy for Hepatocellular Carcinoma: A Multicenter Study of 1206 Patients.

BACKGROUND: Assessment of quality in the perioperative period is critical to ensure good patient care. Textbook outcomes (TO) have been proposed to combine several parameters into a single defined quality metric. The association of preoperative body mass index (BMI) with incidences of achieving or not achieving TO (non-TO) among patients undergoing hepatectomy for hepatocellular carcinoma (HCC) was characterized. METHODS: Patients who underwent curative-intent hepatectomy for HCC between 2015 and 2018 were identified from a multicenter database. These patients were divided into three groups based on preoperative BMI: low-BMI (≤ 18.4 kg/m2), normal-BMI (18.5-24.9 kg/m2), and high-BMI (≥ 25.0 kg/m2). The incidences of non-TO among these three groups were compared. Multivariate analyses were performed to identify whether there was any independent association between preoperative BMI and non-TO. RESULTS: Among 1206 patients, 100 (8.3%), 660 (54.7%), and 446 (37.0%) were in the low-BMI, normal-BMI, and high-BMI groups, respectively. The incidence of non-TO was 65.6% in the whole cohort. The incidence of non-TO was significantly higher among patients in the low- and high-BMI cohorts versus the normal-BMI cohort (75.0% and 74.7% versus 58.0%, both P < 0.01). After adjustment of other confounding factors on multivariate analysis, low-BMI and high-BMI were independently associated with higher incidences of non-TO compared with normal-BMI (OR: 1.98 and 2.27, both P < 0.05). CONCLUSIONS: Two out of three patients did not achieve TO after hepatectomy for HCC. Both preoperative low-BMI and high-BMI were independently associated with lower odds to achieve optimal TO following HCC resection.

Calpain inhibitors inhibit mitochondrial calpain activity to ameliorate apoptosis of cocultured myoblast.

Cancer cachexia is a fatal syndrome associated with muscle regeneration disability. Tumor factors induce the apoptosis of myoblasts to impair the regeneration of skeletal muscle. Cancer cachectic myoblast apoptosis is associated with mitochondria injury. It has been reported that activated mitochondrial calpain caused mitochondria injury in mouse cardiomyocytes and pulmonary smooth muscle. We wondered if mitochondrial calpains exist in skeletal myoblast and their potential role in myoblast apoptosis of cancer cachexia. We used a transwell to build a novel myoblast-carcinoma cell coculture model to simulate the cancer cachexia environment in vitro. Calpain inhibitors, calpastatin (CAST) and calpeptin (CAPT), were used during coculture. We found for the first time that two calpains (calpain-1 and calpain-2) and CAST were present in the mitochondria of myoblast. The activation of mitochondrial calpain decreased mitochondrial complex I activity, promoted mitochondrial permeability transition pore opening, and impaired mitochondrial membrane potential in myoblast during coculture, which induced myoblasts apoptosis. CAST and CAPT protected myoblasts from apoptosis by inhibiting mitochondrial calpain activity, which may attenuate or even reverse cancer cachectic muscle atrophy by improving muscle regeneration ability. Our study provides a new perspective for understanding the mechanism of cancer cachexia, and will further contribute to treat cancer cachexia by focusing on the mitochondrial calpain activity.

Mannan-binding lectin attenuates acetaminophen-induced hepatotoxicity by regulating CYP2E1 expression via ROS-dependent JNK/SP1 pathway.

Mannan-binding lectin (MBL) acts as a soluble pattern recognition molecule in the innate immune system, which is primarily produced by the liver. MBL deficiency occurs with high frequency in the population and is reported to be associated with susceptibility to several liver diseases. In the present study, we investigated the pathophysiological role of MBL in acetaminophen (APAP)-induced hepatotoxicity. After APAP treatment, MBL-deficient (MBL-/- ) mice had significantly higher mortality and aggravated hepatic necrosis as well as elevated serum lactate dehydrogenase and alanine aminotransferase levels compared to control mice. The enhanced hepatotoxicity in MBL-/- mice was associated with increased concentration of APAP toxic metabolisms. Furthermore, we demonstrated here that genetic ablation of MBL resulted in excessive reactive oxygen species (ROS) production and enhanced c-Jun N-terminal kinase (JNK) activation, leading to up-regulated specificity protein 1 (SP1) nuclear expression, thus promoted CYP2E1 hepatic expression and consequently exacerbated APAP-induced liver injury in mice. Importantly, we have validated that MBL protected against APAP toxicity in human HepaRG cells in vitro with the same mechanism. Our study revealed an unexpected function of MBL in drug metabolism, thus providing new insight into the drug-induced liver injury in patients with MBL deficiency.

Mannan-Binding Lectin Regulates Inflammatory Cytokine Production, Proliferation, and Cytotoxicity of Human Peripheral Natural Killer Cells.

Natural killer (NK) cells represent the founding members of innate lymphoid cells (ILC) and play critical roles in inflammation and the immune response. NK cell effector functions are regulated and fine-tuned by various immune modulators. Mannan (or mannose)-binding lectin (MBL), a soluble C-type lectin, is traditionally recognized as an initiator of the complement pathway. Recently, it is also considered as an immunomodulator by its interaction with kinds of immune cells. However, the effect of MBL on NK cell function remains unexplored. In this study, we found that human plasma MBL could interact directly with peripheral NK cells partially via its collagen-like region (CLR). This MBL binding markedly suppressed the interleukin-2- (IL-2-) induced inflammatory cytokine tumor necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ) production but increased the IL-10 production in NK cells. In addition, the expression of activation surface markers such as CD25 and CD69 declined after MBL treatment. Also, MBL impaired the proliferation and lymphokine-activated killing (LAK) of NK cells. Moreover, we demonstrated that MBL inhibited IL-2-induced signal transducers and activators of transcription 5 (STAT5) activation in NK cells. In conclusion, we have uncovered a far unknown regulatory role of MBL on NK cells, a new clue that could be important in the immunomodulatory networks of immune responses.

Macrophage scavenger receptor 1 contributes to pathogenesis of fulminant hepatitis via neutrophil-mediated complement activation.

BACKGROUND & AIMS: The macrophage scavenger receptor 1 (Msr1, also called SRA) is a pattern recognition receptor primarily expressed on myeloid cells, which plays an important role in the maintenance of immune homeostasis. Since MSR1 expression was upregulated in the livers of patients with fulminant hepatitis (FH), we investigated the functional mechanism of Msr1 in FH pathogenesis. METHODS: Msr1-deficient (Msr1-/-) mice and their wild-type (WT) littermates were infected with mouse hepatitis virus strain-A59 (MHV-A59) to induce FH, and the levels of tissue damage, serum alanine aminotransferase, inflammatory cytokines and complement component 5a (C5a) were measured and compared. Liver injury was studied after MHV infection with or without neutrophil depletion. RESULTS: Our results showed that Msr1-/- mice were resistant to MHV-induced hepatitis. Treatment with the C5a receptor antagonist (C5aRa) diminished the differences in inflammatory responses and liver injury between MHV-infected wild-type and Msr1-/- mice, suggesting that C5a-induced pro-inflammatory response plays a critical role in the Msr1-mediated regulation of FH pathogenesis. We demonstrated that Msr1 efficiently enhanced transforming growth factor-activated kinase-1 phosphorylation in neutrophils upon MHV-A59 stimulation, thereby promoting the activation of the extracellular signal-regulated kinase pathway and subsequent NETosis formation. Moreover, we provided evidence that blockage of Msr1 attenuated the liver damage caused by MHV-A59 infection. CONCLUSIONS: Msr1 promotes the pathogenesis of virus-induced FH by enhancing induction of neutrophil NETosis and subsequent complement activation. Targeting Msr1 may be employed as a new immunotherapeutic strategy for FH. LAY SUMMARY: Virus-induced fulminant hepatitis (FH) is a disease with a high mortality worldwide. Enhanced levels of macrophage scavenger receptor 1 (Msr1) in the liver of patients with FH and of murine experimental FH indicated Msr1 plays a role in the pathogenesis of FH. Herein, we demonstrate that mice deficient in Msr1 are resistant to FH induced by MHV-A59, and the Msr1 inhibitor fucoidan suppresses the progression of FH in mice. Our study suggests that use of drugs inhibiting MSR1 function could be beneficial to patients with FH.

Mannan-binding lectin, a serum collectin, suppresses T-cell proliferation via direct interaction with cell surface calreticulin and inhibition of proximal T-cell receptor signaling.

Mannan binding lectin (MBL), initially reported to activate the complement pathway, is also known to be involved in the pathogenesis of autoimmune diseases. We report a thus far unknown function of MBL as a suppressor of T-cell activation. MBL markedly inhibited T-cell proliferation induced by anti-CD3 and anti-CD28 antibodies. Moreover, the presence of MBL during T-cell priming interfered with proximal T-cell receptor signaling by decreasing phosphorylation of Lck, ZAP-70, and LAT. MBL bound to T cells through interaction between the collagen-like region of MBL and calreticulin (CRT) expressed on the T-cell surface. The neutralizing antibody against CRT abrogated MBL-mediated suppression of T-cell proliferation, suggesting that MBL down-modulates T-cell proliferation via cell surface CRT. We further demonstrated that the feature of MBL-mediated T-cell suppression is shared by other serum collectins (e.g., C1q and collectin 11). The concentrations of MBL correlated negatively with in vivo T-cell activation status in patients with early-stage silicosis. Furthermore, MBL efficiently inhibited activation and proliferation of autoreactive T cells derived from patients with silicosis, indicating that MBL serves as a negative feedback control of the T-cell responses.-Zhao, N., Wu, J., Xiong, S., Zhang, L., Lu, X., Chen, S., Wu, Q., Wang, H., Liu, Y., Chen, Z., Zuo, D. Mannan-binding lectin, a serum collectin, suppresses T-cell proliferation via direct interaction with cell surface calreticulin and inhibition of proximal T-cell receptor signaling.

Fucoidan from Fucus vesiculosus suppresses hepatitis B virus replication by enhancing extracellular signal-regulated Kinase activation.

BACKGROUND: Hepatitis B virus (HBV) infection is a serious public health problem leading to cirrhosis and hepatocellular carcinoma. As the clinical utility of current therapies is limited, the development of new therapeutic approaches for the prevention and treatment of HBV infection is imperative. Fucoidan is a natural sulfated polysaccharide that extracted from different species of brown seaweed, which was reported to exhibit various bioactivities. However, it remains unclear whether fucoidan influences HBV replication or not. METHODS: The HBV-infected mouse model was established by hydrodynamic injection of HBV replicative plasmid, and the mice were treated with saline or fucoidan respectively. Besides, we also tested the inhibitory effect of fucoidan against HBV infection in HBV-transfected cell lines. RESULTS: The result showed that fucoidan from Fucus vesiculosus decreased serum HBV DNA, HBsAg and HBeAg levels and hepatic HBcAg expression in HBV-infected mice. Moreover, fucoidan treatment also suppressed intracellular HBcAg expression and the secretion of the HBV DNA as well as HBsAg and HBeAg in HBV-expressing cells. Furthermore, we proved that the inhibitory activity by fucoidan was due to the activation of the extracellular signal-regulated kinase (ERK) pathway and the subsequent production of type I interferon. Using specific inhibitor of ERK pathway abrogated the fucoidan-mediated inhibition of HBV replication. CONCLUSION: This study highlights that fucoidan might be served as an alternative therapeutic approach for the treatment of HBV infection.

Polysaccharide extracted from Chinese white wax scale ameliorates 2,4-dinitrochlorobenzene-induced atopic dermatitis-like symptoms in BALB/c mice.

Atopic dermatitis (AD) is a common inflammatory skin disease with high rates of morbidity and is associated with erythema, pruritus, scaling of affected areas of skin. It is extremely important to introduce a therapeutic agent which has significant anti-inflammatory effect with less side-effect for treatment of AD. This study evaluated the effect of a natural compound from herbal extracts, the crude polysaccharide extracted from the white wax scale (CWPS), on AD-like mice. Repeated applications of 2,4-dinitrochlorobenzene (DNCB) were performed on ear and dorsal skin of BALB/c mice to induce AD-like symptoms and skin lesions. Oral administration of CWPS decreased serum IgE level and limited the infiltration of mast cells and eosinophils to the dermal tissues in the DNCB-induced AD mice. In addition, CWPS reduced Th1 and Th17 responses, leading to an attenuated cutaneous inflammatory response. Furthermore, in vitro study also demonstrated that CWPS limited T cell activation and cytokines (i.e. IFN-γ and IL-17) production induced by DNCB. We conclude that CWPS attenuates DNCB-induced AD-like skin lesion through modulating T cell-elicited immune responses and CD4+ T cell polarization, and could be exploited as a new therapeutic approach for AD.

Involvement of soluble scavenger receptor A in suppression of T cell activation in patients with chronic hepatitis B.

BACKGROUND: Scavenger receptor A (SRA) is expressed predominantly in phagocytic cells playing an essential role in the host immune defense against invading microorganisms. Our previous study reported the presence of SRA in a soluble form in patients with infection of hepatitis B viruses (HBV). However, the association of soluble SRA with stages of HBV infection and the immune response induced by HBV is not fully determined. METHODS: In this study, we detected soluble SRA in serum from 29 chronic hepatitis B (CHB) patients, 28 chronic HBV carriers in the immune tolerant (IT) stage, 33 in the HBeAg-negative inactive carrier (IC) stage, and 22 healthy controls (HCs), respectively. We further analyzed the correlation of detected soluble SRA to inflammation and serum viral load. In addition, we investigated the regulatory role of soluble SRA in T cell activation, especially in CD8(+) T cell response to HBV peptide. RESULTS: We demonstrated that Median levels of serum soluble SRA in CHB and IT patients were significantly higher than those of IC patients and HCs. Additionally, the concentrations of soluble SRA were negatively correlated with alanine transaminase levels in CHB patients. We also found that serum concentration of SRA was decreased during telbivudine treatment. Expressed SRA extracellular domain suppressed HBV core peptide-stimulated interferon-γ and tumor necrosis factor-α production in CD8(+) T cells, and it bound to T cells in a higher frequency in CHB patients than in HCs. Furthermore, we observed that naïve human T cells stimulated by anti-CD3 and CD28 antibodies in the presence of the recombinant SRA protein had reduced activation and proliferation. CONCLUSION: In summary, we determined the level of soluble SRA in different stages of CHB patients. SRA might inhibit T cell proliferation and activation as a soluble form. These results not only revealed a previously unknown feature of soluble SRA in CHB patients but also provided broad understanding of SRA in T cell activation.

Mannan-binding lectin reduces CpG DNA-induced inflammatory cytokine production by human monocytes.

Mannan-binding lectin (MBL) belongs to the collectin family and functions as an opsonin that can also initiate complement activation. Our previous study showed that MBL serves as a double-stranded RNA binding protein that attenuates polyriboinosinic-polyribocytidylic acid-induced TLR3 activation. Prompted by these findings, in the present study cross-talk between MBL and CpG-DNA-induced TLR9 activation was investigated. Here, it was found that MBL also interacts with the TLR9 agonist, CpG oligodeoxynucleotide (CpG-ODN), in a calcium-dependent manner. Purified MBL protein suppressed activation of nuclear factor-kappa B signaling and subsequent production of proinflammatory cytokines from human monocytes induced by CpG-ODN 2006. These observations indicate that MBL can down-regulate CpG DNA-induced TLR9 activation, emphasizing the importance of understanding the interaction of MBL with TLR agonist in host immune defense.

Mannan-binding lectin at supraphysiological concentrations inhibits differentiation of dendritic cells from human CD14+ monocytes.

Mannan-binding lectin (MBL), a circulating C-type lectin, is an important member of the defense collagen family. It exhibits a high potential for recognizing broad categories of pathogen-associated molecular patterns and initiating complement cascade responses. DCs are well-known specialist antigen-presenting cells that significantly trigger specific T cell-mediated immune responses. In our previous study, it was observed that high concentrations of MBL significantly attenuate LPS-induced maturation of monocyte-derived DCs (MoDCs). In the current study, it was postulated that MBL at similar supraphysiological concentrations would affect early differentiation of MoDCs in some way. CD14(+) monocytes from human peripheral blood mononuclear cells were cultured with granulocyte-macrophage colony-stimulating factor and IL-4 in the presence or absence of physiological (1 µg/mL) and supraphysiological concentrations (20 µg/mL) of MBL protein, respectively. Phenotypic analysis indicated that the differentiated DCs incubated with high concentrations of MBL expressed MHC class II and costimulatory molecules (e.g., CD80 and CD40) more weakly than did control groups. The secretion of IL-10 and IL-6 increased markedly, whereas their mixed lymphocyte reaction-stimulating capacity decreased. Members of the signal transducer and activator of transcription family were also found to be differentially regulated. Thus, beyond the role of MBL as an opsonin, our data reveal a possible inhibitory effect of MBL at high concentrations in monocyte-DC transition, which probably provides one way of regulating adaptive immune responses by strict regulation of DCs, making MBL a better prospect for controlling relevant pathological events such as autoimmune diseases.

Mutual blood donation is safer at small blood collection stations in China.

BACKGROUND: The assumption that the level of safety of voluntary non-remunerated donors is significantly higher than that of family replacement donors is supported by global data without stratifying for first-time or repeat volunteer, or according to age, but the viral marker prevalence between replacement donors and first-time voluntary non-remunerated donors is similar. MATERIALS AND METHODS: From 2006 to 2013, replacement and voluntary donors were respectively recruited by the hospitals and the Center Blood Station in Zhaoqing, Guangdong, according to the existing procedures, and all the donors were screened for hepatitis B virus (HBV) surface antigen (HBsAg), antibodies against hepatitis C virus (anti-HCV), human immunodeficiency virus (anti-HIV) (1 + 2) and Treponema pallidum (anti-TP) by the enzyme immunoassays (EIAs), and alanine aminotransferase (ALT) in the Center Blood Station by kinetic analysis method. The risk factors related to blood safety were analyzed by Binary logistic regression analysis. RESULTS: Between 252,202 volunteers and 2771 replacement donors, the prevalences of ALT > 40 U/L and anti-HIV (4.88% and 0.01% vs 4.44% and 0.07%, respectively) were not significantly different. The prevalences of HBsAg, anti-HCV and anti-syphilis in replacement group were higher than those in voluntary group, which were related to donor's sex, age and donation time. Overall prevalence of serological markers was higher in male replacement donors than in female, and in replacement donor over 30 years than in those below 30 years, but the positive prevalence in repeated replacement donors was lower than that in first-time replacement donors. CONCLUSIONS: With appropriate intervention measures, such as pre-donor screening and other donor selection policy, replacement donors and voluntary donors provide a similar level of viral safety. Our donor selection policy in future should focus on retaining both young replacement and young voluntary donors as repeat donors and promoting the donation proportion of females, which will improve blood safety.

Scavenger receptor A restrains T-cell activation and protects against concanavalin A-induced hepatic injury.

UNLABELLED: Negative feedback immune mechanisms are essential for maintenance of hepatic homeostasis and prevention of immune-mediated liver injury. We show here that scavenger receptor A (SRA/CD204), a pattern recognition molecule, is highly up-regulated in the livers of patients with autoimmune or viral hepatitis, and of mice during concanavalin A (Con A)-induced hepatitis (CIH). Strikingly, genetic SRA ablation strongly sensitizes mice to Con A-induced liver injury. SRA loss, increased mortality and liver pathology correlate with excessive production of IFN-γ and heightened activation of T cells. Increased liver expression of SRA primarily occurs in mobilized hepatic myeloid cells during CIH, including CD11b(+) Gr-1(+) cells. Mechanistic studies establish that SRA on these cells functions as a negative regulator limiting T-cell activity and cytokine production. SRA-mediated protection from CIH is further validated by adoptive transfer of SRA(+) hepatic mononuclear cells or administration of a lentivirus-expressing SRA, which effectively ameliorates Con A-induced hepatic injury. Also, CIH and clinical hepatitis are associated with increased levels of soluble SRA. This soluble SRA displays a direct T-cell inhibitory effect and is capable of mitigating Con A-induced liver pathology. CONCLUSION: Our findings demonstrate an unexpected role of SRA in attenuation of Con A-induced, T-cell-mediated hepatic injury. We propose that SRA serves as an important negative feedback mechanism in liver immune homeostasis, and may be exploited for therapeutic treatment of inflammatory liver diseases.

Molecular chaperoning by glucose-regulated protein 170 in the extracellular milieu promotes macrophage-mediated pathogen sensing and innate immunity.

Recognition of pathogen-associated molecular patterns by innate immune receptors is essential for host defense responses. Although extracellular stress proteins are considered as indicators of the stressful conditions (e.g., infection or cell injury), the exact roles of these molecules in the extracellular milieu remain less defined. We found that glucose-regulated protein 170 (Grp170), the largest stress protein and molecular chaperone, is highly efficient in binding CpG oligodeoxynucleotides (CpG-ODN), the microbial DNA mimetic sensed by toll-like receptor 9 (TLR9). Extracellular Grp170 markedly potentiates the endocytosis and internalization of CpG-ODN by mouse bone marrow-derived macrophages and directly interacts with endosomal TLR9 on cell entry. These molecular collaborations result in the synergistic activation of the MyD88-dependent signaling and enhanced production of proinflammatory cytokines and nitric oxide in mouse primary macrophages as well as human THP-1 monocyte-derived macrophages, suggesting that Grp170 released from injured cells facilitates the sensing of pathogen-associated "danger" signals by intracellular receptors. This CpG-ODN chaperone complex-promoted innate immunity confers increased resistance in mice to infection of Listeria monocytogenes compared with CpG-ODN treatment alone. Our studies reveal a previously unrecognized attribute of Grp170 as a superior DNA-binding chaperone capable of amplifying TLR9 activation on pathogen recognition, which provides a conceptual advance in understanding the dynamics of ancient chaperoning functions inside and outside the cell.