Heparin-Functionalized Adsorbents Eliminate Central Effectors of Immunothrombosis, including Platelet Factor 4, High-Mobility Group Box 1 Protein and Histones.

Inflammation and thrombosis are closely intertwined in numerous disorders, including ischemic events and sepsis, as well as coronavirus disease 2019 (COVID-19). Thrombotic complications are markers of disease severity in both sepsis and COVID-19 and are associated with multiorgan failure and increased mortality. Immunothrombosis is driven by the complement/tissue factor/neutrophil axis, as well as by activated platelets, which can trigger the release of neutrophil extracellular traps (NETs) and release further effectors of immunothrombosis, including platelet factor 4 (PF4/CXCL4) and high-mobility box 1 protein (HMGB1). Many of the central effectors of deregulated immunothrombosis, including activated platelets and platelet-derived extracellular vesicles (pEVs) expressing PF4, soluble PF4, HMGB1, histones, as well as histone-decorated NETs, are positively charged and thus bind to heparin. Here, we provide evidence that adsorbents functionalized with endpoint-attached heparin efficiently deplete activated platelets, pEVs, PF4, HMGB1 and histones/nucleosomes. We propose that this elimination of central effectors of immunothrombosis, rather than direct binding of pathogens, could be of clinical relevance for mitigating thrombotic complications in sepsis or COVID-19 using heparin-functionalized adsorbents.

Rationale of Blood Purification in the Post-Resuscitation Syndrome following Out-of-Hospital Cardiac Arrest: A Narrative Review.

Even today, little is known about the pathophysiology of the post-resuscitation syndrome. Our narrative review is one of the first summarizing all the knowledge about this phenomenon. We have focused our review upon the potential role of blood purification in attenuating the consequences of the post-resuscitation syndrome. Blood purification can decrease the cytokine storm particularly when using a CytoSorb absorber. Acrylonitrile 69-based oXiris membranes can remove endotoxin and high-mobility group box 1 protein. Blood purification techniques can quickly induce hypothermia. Blood purification can be used with veno-arterial extracorporeal membrane oxygenation to remove excess water. Further trials are needed to provide more concrete data about the use of blood purification in the post-resuscitation syndrome.

Plasma Adsorption Membranes Are Able to Efficiently Remove High Mobility Group Box-1 (HMGB-1).

BACKGROUND: High Mobility Group Box 1 (HMGB-1) is a 30 kDa protein that is a lethal mediator in sepsis and is a recognized therapeutic target. However, no consensus has been reached for acute blood purification therapy as a treatment for sepsis targeting HMGB-1. Previous studies demonstrated that a high anti-HMGB-1 antibody titer and the suppression of HMGB-1 activity improved survival rate in animal sepsis models. The aim of this study was to evaluate whether plasma adsorption therapy is able to decrease the level of HMGB-1, representing a new potential treatment strategy against sepsis. METHODS: Plasma adsorption therapy has been known as a treatment for various autoimmune diseases. Three different adsorbent columns, including TR-350 (IM-TR), PH-350 (IM-PH), and BRS-350 (BRS), were used in this study for comparison. We made a 1/350 scale of these three columns. Fetal bovine serum (FBS) contains a significant amount of HMGB-1. After priming with saline, FBS was passed through the columns and the adsorption rates of HMGB-1 at 25 minutes, 50 minutes, and 75 minutes were evaluated. The total adsorbed HMGB-1 level at 75 minutes was also calculated. RESULTS: The highest adsorption rate and total adsorbed amount of HMGB-1 were observed in IM-TR, followed by BRS and IM-PH. IM-TR showed a decline in adsorption rate over time. BRS showed a steady adsorption rate at all time points. IM-TR removed HMGB-1 significantly more than IM-PH and BRS. CONCLUSIONS: Our findings showed that plasma adsorption therapy efficiently adsorbed HMGB-1 and could be safely applied for the treatment of sepsis.

Adiponectin suppression of late inflammatory mediator, HMGB1-induced cytokine expression in RAW264 macrophage cells.

High-mobility group protein B1 (HMGB1) is a late inflammatory mediator released from inflammatory cells when stimulated, resulting in exaggerating septic symptoms. We recently demonstrated that full-length adiponectin, a potent anti-inflammatory adipokine, inhibits lipopolysaccharide-induced HMGB1 release. However, the effects of adiponectin on HMGB1-induced exaggerating signals currently remain unknown. This study aimed to investigate the effects of adiponectin on the pro-inflammatory function of HMGB1 in RAW264 macrophage cells. The treatment of RAW264 cells with HMGB1 significantly up-regulated the mRNA expression of tumour necrosis factor-α, interleukin-1ß and C-X-C motif chemokine 10. HMGB1-induced cytokine expression was markedly suppressed by a toll-like receptor 4 (TLR4) antagonist and slightly suppressed by an antagonist of the receptor for advanced glycation end products. A prior treatment with full-length or globular adiponectin dose-dependently suppressed all types of HMGB1-induced cytokine expression, and this suppression was abolished by compound C, an AMPK inhibitor, but not by the haem oxygenase (HO)-1 inhibitor, zinc protoporphyrin IX. Both forms of adiponectin also reduced the mRNA expression of TLR4. These results suggest that full-length and globular adiponectin suppress HMGB1-induced cytokine expression through an AMPK-mediated HO-1-independent pathway.

[Prokaryotic expression and purification of recombinant rat HMGB1-A].

Objective To obtain the recombinant A-domain of high mobility group box 1 (HMGB1-A) protein. Methods Using genetic engineering techniques, we cloned and recombined rat HMGB1-A gene. Using prokaryotic expression technique, we expressed and purified the recombinant rat HMGB1-A protein, which was verified by Western blotting. Results Agarose gel electrophoresis analysis showed that HMGB1-A cassette gene size was about 250 bp; double digestion for identifying the recombinant clone pUC-A showed that the product size was about 3000 bp, 250 bp; PCR for identifying the recombinant clone pGEX-A showed that the product size was about 250 bp. SDS-PAGE revealed that the product size was about 36 000, which was consistent with the expectation. Conclusion The recombinant rat HMGB1-A was successfully expressed and purified.

Optimization of surface plasmon resonance experiments: Case of high mobility group box 1 (HMGB1) interactions.

Surface plasmon resonance (SPR) is a powerful technique for evaluating protein-protein interactions in real time. However, inappropriately optimized experiments can often lead to problems in the interpretation of data, leading to unreliable kinetic constants and binding models. Optimization of SPR experiments involving "sticky" proteins, or proteins that tend to aggregate, represents a typical scenario where it is important to minimize errors in the data and the kinetic analysis of those data. This is the case of High Mobility Group Box 1 and the receptor of advanced glycation end products. A number of improvements in protein purification, buffer composition, immobilization conditions, and the choice of flow rate are shown to result in substantial improvements in the accurate characterization of the interactions of these proteins and the derivation of the corresponding kinetic constants.

Evaluating cytoplasmic and nuclear levels of inflammatory cytokines in cancer cells by western blotting.

Increased expression and cellular release of inflammatory cytokines, interleukin-8 (IL-8; CXCL8), and high mobility group box-1 (HMGB1) are associated with increased cell proliferation, angiogenesis, and metastasis during cancer progression. In prostate and ovarian cancer cells, increased levels of IL-8 and HMGB1 correlate with poor prognosis. We have recently shown that proteasome inhibition by bortezomib (BZ) specifically increases IL-8 release from metastatic prostate and ovarian cancer cells. In this chapter, we describe a protocol to analyze the cytoplasmic and nuclear levels of IL-8 and HMGB1 in prostate and ovarian cancer cells by western blotting. IL-8 is localized in the cytoplasm in both cell types, and its protein levels are significantly increased by BZ. In contrast, HMGB1 is localized in the nucleus, and BZ increases its nuclear levels only in ovarian cancer cells. The protocol includes isolation of cytoplasmic and nuclear extracts, followed by SDS electrophoresis and western blotting, and can be easily modified to analyze the cytoplasmic and nuclear cytokine levels in other cell types.

Hemoadsorption of high-mobility group box chromosomal protein 1 using a column for large animals.

BACKGROUND: High-mobility group box chromosomal protein 1 (HMGB1) has recently been identified as an important mediator of various kinds of acute and chronic inflammation. A method for efficiently removing HMGB1 from the systemic circulation could be a promising therapy for HMGB1-mediated inflammatory diseases. MATERIALS AND METHODS: In this study, we produced a new adsorbent material by chemically treating polystyrene fiber. We first determined whether the adsorbent material efficiently adsorbed HMGB1 in vitro using a bovine HMGB1 solution and a plasma sample from a swine model of acute liver failure. We then constructed a column by embedding fabric sheets of the newly developed fibers into a cartridge and tested the ability of the column to reduce plasma HMGB1 levels during a 4-hour extracorporeal hemoperfusion in a swine model of acute liver failure. RESULTS: The in vitro adsorption test of the new fiber showed high performance for HMGB1 adsorption (96% adsorption in the bovine HMGB1 solution and 94% in the acute liver failure swine plasma, 2 h incubation at 37°C; p < 0.05 vs. incubation with no adsorbent). In the in vivo study, the ratio of the HMGB1 concentration at the outlet versus the inlet of the column was significantly lower in swine hemoperfused with the newly developed column (53 and 61% at the beginning and end of perfusion, respectively) than in those animals hemoperfused with the control column (94 and 93% at the beginning and end of perfusion, respectively; p < 0.05). Moreover, the normalized plasma level of HMGB1 was significantly lower during perfusion with the new column than with the control column (p < 0.05 at 1, 2, and 3 h after initiation of perfusion). CONCLUSION: These data suggest that the newly developed column has the potential to effectively adsorb HMGB1 during hemoperfusion in swine.

HMGB1-facilitated p53 DNA binding occurs via HMG-Box/p53 transactivation domain interaction, regulated by the acidic tail.

Facilitated binding of p53 to DNA by high mobility group B1 (HMGB1) may involve interaction between the N-terminal region of p53 and the high mobility group (HMG) boxes, as well as HMG-induced bending of the DNA. Intramolecular shielding of the boxes by the HMGB1 acidic tail results in an unstable complex with p53 until the tail is truncated to half its length, at which point the A box, proposed to be the preferred binding site for p53(1-93), is exposed, leaving the B box to bind and bend DNA. The A box interacts with residues 38-61 (TAD2) of the p53 transactivation domain. Residues 19-26 (TAD1) bind weakly, but only in the context of p53(1-93) and not as a free TAD1 peptide. We have solved the structure of the A-box/p53(1-93) complex by nuclear magnetic resonance spectroscopy. The incipient amphipathic helix in TAD2 recognizes the concave DNA-binding face of the A box and may be acting as a single-stranded DNA mimic.

The dengue vector Aedes aegypti contains a functional high mobility group box 1 (HMGB1) protein with a unique regulatory C-terminus.

The mosquito Aedes aegypti can spread the dengue, chikungunya and yellow fever viruses. Thus, the search for key molecules involved in the mosquito survival represents today a promising vector control strategy. High Mobility Group Box (HMGB) proteins are essential nuclear factors that maintain the high-order structure of chromatin, keeping eukaryotic cells viable. Outside the nucleus, secreted HMGB proteins could alert the innate immune system to foreign antigens and trigger the initiation of host defenses. In this work, we cloned and functionally characterized the HMGB1 protein from Aedes aegypti (AaHMGB1). The AaHMGB1 protein typically consists of two HMG-box DNA binding domains and an acidic C-terminus. Interestingly, AaHMGB1 contains a unique alanine/glutamine-rich (AQ-rich) C-terminal region that seems to be exclusive of dipteran HMGB proteins. AaHMGB1 is localized to the cell nucleus, mainly associated with heterochromatin. Circular dichroism analyses of AaHMGB1 or the C-terminal truncated proteins revealed α-helical structures. We showed that AaHMGB1 can effectively bind and change the topology of DNA, and that the AQ-rich and the C-terminal acidic regions can modulate its ability to promote DNA supercoiling, as well as its preference to bind supercoiled DNA. AaHMGB1 is phosphorylated by PKA and PKC, but not by CK2. Importantly, phosphorylation of AaHMGB1 by PKA or PKC completely abolishes its DNA bending activity. Thus, our study shows that a functional HMGB1 protein occurs in Aedes aegypt and we provide the first description of a HMGB1 protein containing an AQ-rich regulatory C-terminus.

[Purification and identification of HMGB1 secreted by liver cells and immune cells].

OBJECTIVE: To purify and identify HMGB1 secreted by liver cells HepG2 and immune cells U937. METHODS: We cultured the liver cell lines HepG2 and immune cell lines U937, and stimulated them with HMGB1 (400 ng/mL) for 20 h. Then the supernatant was collected. Ultrafiltration centrifugation, CM-Sepharose cation, DEAE-Sepharose anion exchange chromatography, Sephadex G75-gel filtration chromatography, and immunoprecipitation were used for purification. The molecular weight and identity of HMGB1 was confirmed by SDS-PAGE and Western blot. RESULTS: A sharp stained protein band with a molecular weight of about 26 kD was obtained by SDS-PAGE analysis and shown to be HMGB1 confirmed by Western blot. CONCLUSION: High purified HMGB1 can be separated from these two cell lines.

Production of recombinant human HMGB1 and anti-HMGB1 rabbit serum.

High-mobility group box-1 (HMGB1) plays important roles in inflammation, immune responses, and tumor progression. Since HMGB1 and its components have been shown to be mediators of a number of diseases but several sources of recombinant HMGB1 showed controversial biological activity, it is important to obtain recombinant HMGB1 with properties that resemble the native protein. For this purpose, we cloned genes coding for human HMGB1 and its active components A box and B box by PCR and inserted the cloned genes into pET28a vectors for transformation of Escherichia coli BL21. The E. coli expressed proteins were then purified with a Ni(2+)-NTA column and the endotoxin content was removed. Recombinant human HMGB1 (rhHMGB1) and its B box thus obtained stimulated, but A box inhibited, the production of the chemokine CXCL8/IL-8 by THP-1 monocytic cell line. We also used purified rhHMGB1 to immunize rabbits and generated potent anti-sera, which was capable of neutralizing the activity of rhHMGB1 in vitro and detecting the increased HMGB1 expression in inflammatory tissues in mice and humans. Thus, we have established essential means to produce biologically active rhHMGB1 that will facilitate us to study its role in diseases and to explore its potential as a therapeutic agent.

[Expression of human HMGB1 A box in E. coli and its inhibitory effects on monocytes].

AIM: To clone human high mobility guoup box1 A box (HMGB1 A box) and express it in escherichia coli effectly, investigate the inhibit effection of the purpose protern to the activation of monocytes stimulated by immunocomplex. METHODS: According to human HMGB1 gene order which was optimized by our laboratory the PCR primer was designed which containing restriction enzyme cutting site. The HMGB1 A box gene was cloned following the whole gene synthesis template of human HMGB1, then the PCR product was inserted into clone vector pMD19-T. The positive colone was identified by colony PCR, zymography analysis and DNA sequencing. Recombinant colne vector was digested by restriction enzymes Nde I and Xho I and separated by agarose gel electrophoresis, then the fragment was inserted into the corresponding sites of expression vector pQE-T7-2. The positive recombinant expression vector was identified by colony PCR and the recombinant strains was induced by IPTG, then the purpose protein was identified by SDS-PAGE and Western blot. The recombinant protein of human HMGB1 A box was purificated by Ni(2+)-NTA chromatography and the inhibit effection of the purpose protern to the activation of monocyte stimulated by immunocomplex was identified by RT-PCR. RESULTS: We acquired expression strains of recombinant human HMGB1 A box, the target protein account for up to 40% of the whole protein of E.coli. Western blot showed recombinant protein can specificly reacted with anti-human HMGB1 polyclonal antibody and anti-His-Tag polyclonal antibody.The purpose protein was found more than 90% after purified, and can effectively inhibit the production of BAFF, IFN-gamma and TNF-alpha in monocyte which were induced by IC. CONCLUSION: A recombinant bacterial strain for expressing human HMGB1A box with biological activities was constructed successfully.

The alarmin HMGB1 acts in synergy with endogenous and exogenous danger signals to promote inflammation.

The nuclear protein HMGB1 has previously been demonstrated to act as an alarmin and to promote inflammation upon extracellular release, yet its mode of action is still not well defined. Access to highly purified HMGB1 preparations from prokaryotic and eukaryotic sources enabled studies of activation of human PBMC or synovial fibroblast cultures in response to HMGB1 alone or after binding to cofactors. HMGB1 on its own could not induce detectable IL-6 production. However, strong enhancing effects on induction of proinflammatory cytokine production occurred when the protein associated with each of the separate proinflammatory molecules, rhIL-1beta, the TLR4 ligand LPS, the TLR9 ligand CpG-ODN, or the TLR1-TLR2 ligand Pam3CSK4. The bioactivities were recorded in cocultures with preformed HMGB1 complexes but not after sequential or simultaneous addition of HMGB1 and the individual ligands. Individual A-box and B-box domains of HMGB1 had the ability to bind LPS and enhance IL-6 production. Heat denaturation of HMGB1 eliminated this enhancement. Cocultures with HMGB1 and other proinflammatory molecules such as TNF, RANKL, or IL-18 did not induce enhancement. HMGB1 thus acts broadly with many but not all immunostimulatory molecules to amplify their activity in a synergistic manner.

Immunogenicity of 56 degrees C and UVC-treated prostate cancer is associated with release of HSP70 and HMGB1 from necrotic cells.

BACKGROUND: Prostate hyperthermia and photodynamic therapy can be delivered by a variety of procedures which result in a wide range of temperatures and light energy and cause different kinds of cell death. METHODS: We have addressed the immunogenic effect of heating and UVC irradiation on the prostate cancer (PCa) cell line LNCaP, by studying the release of Danger Associated Molecule Pattern (DAMP) molecules HSP70 and HMGB1 and the dendritic cell (DC) antigen-presenting efficiency. RESULTS: Intracellular upmodulation and extracellular release of HSP70 were inversely correlated. Mild temperatures (43-47 degrees C) induced an early increase of intracellular HSP70, whereas the highest temperature (56 degrees C) induced its extrusion from the cell. Likewise, UVC caused an immediate migration of HSP70 into the cell medium in the absence of any intracellular modulation. 56 degrees C and UVC also induced a robust release of HMGB1. The release of DAMP molecules was closely associated with post-apoptotic membrane damage, as shown by double Annexin V/propidium iodide staining, whereas beta-tubulin, a structural component of cell membranes, was specifically induced by 56 degrees C heating. Tumor uptake strongly impaired the cytokine-driven maturation of DCs and 56 degrees C heating led to a significant recovery of CD83 and CCR7 DC maturation markers, but did not influence the antigen cross-presentation activity. On the contrary, UVC-treated LNCaP had negligible effects on DC maturation, but increased the cross-priming of tumor specific CTL. CONCLUSIONS: These data may be of use in the design of effective non-surgical PCa ablations that combine tumor destruction with long lasting immunity.

High mobility group box chromosomal protein 1 acts as a proliferation signal for activated T lymphocytes.

The nuclear protein high mobility group box chromosomal protein 1 (HMGB1) can be translocated extracellularly and plays a well-established role as a pro-inflammatory mediator during innate immune responses. Much less is known about the role of HMGB1 in adaptive immunity, since only a few studies have addressed the issue. We herein activated subsets of purified, primary human T lymphocytes with solid-phase bound anti-CD3 mAb and assessed the effects of recombinant HMGB1 protein on cell proliferation when added to the cultures. HMGB1 acted as a proliferative signal for human T cells during suboptimal anti-CD3 mAb stimulation. Statistically significant increased proliferation was recorded in both CD4+ and CD8+ T-cell cultures at HMGB1 concentrations ranging from 0.25 to 1.0 microg/ml. HMGB1 had no effect on proliferation in the absence of anti-CD3 stimulation or during T-cell activation obtained using high doses of anti-CD3 mAb. Our results demonstrate a direct HMGB1-mediated effect in adaptive immunity.

Expression, purification and characterization of TAT-high mobility group box-1A peptide as a carrier of nucleic acids.

High mobility group box 1 (HMGB1) is an abundant nuclear protein that binds to double-stranded DNA. HMGB1 is composed of high mobility (HMG) box A, box B, and C-terminal acidic regions. In this study, a recombinant TAT linked HMGB1 box A (rTAT-HMGB1A) peptide was expressed, purified, and characterized as a carrier of nucleic acids. The HMGB1A cDNA was amplified by PCR, and cloned into the pET21a expression vector with the TAT domain located at the N-terminus. The rTAT-HMGB1A peptide was overexpressed and purified using Nickel affinity chromatography. A recombinant HMGB1A (rHMGB1A) peptide without the TAT domain was also overexpressed and purified as a control. In gel retardation assays, both the rHMGB1A and rTAT-HMGB1A peptides formed complexes with DNA equally well. However, transfection assays showed that the rTAT-HMGB1A peptide had a higher gene transfer efficiency than rHMGB1A. Finally, rTAT-HMGB1A had no cytotoxicity to HEK 293 cells suggesting that rTAT-HMGB1A may be useful as a non-toxic gene delivery carrier.

A critical role in structure-specific DNA binding for the acetylatable lysine residues in HMGB1.

The structure-specific DNA-binding protein HMGB1 (high-mobility group protein B1) which comprises two tandem HMG boxes (A and B) and an acidic C-terminal tail, is acetylated in vivo at Lys(2) and Lys(11) in the A box. Mutation to alanine of both residues in the isolated A domain, which has a strong preference for pre-bent DNA, abolishes binding to four-way junctions and 88 bp DNA minicircles. The same mutations in full-length HMGB1 also abolish its binding to four-way junctions, and binding to minicircles is substantially impaired. In contrast, when the acidic tail is absent (AB di-domain) there is little effect of the double mutation on four-way junction binding, although binding to minicircles is reduced approximately 15-fold. Therefore it appears that in AB the B domain is able to substitute for the non-functional A domain, whereas in full-length HMGB1 the B domain is masked by the acidic tail. In no case does single substitution of Lys(2) or Lys(11) abolish DNA binding. The double mutation does not significantly perturb the structure of the A domain. We conclude that Lys(2) and Lys(11) are critical for binding of the isolated A domain and HMGB1 to distorted DNA substrates.

HMGB1 develops enhanced proinflammatory activity by binding to cytokines.

High mobility group box 1 protein (HMGB1), originally characterized as a nuclear DNA-binding protein, has also been described to have an extracellular role when it is involved in cellular activation and proinflammatory responses. In this study, FLAG-tagged HMGB1 was inducibly expressed in the presence of culture media with or without added IL-1beta, IFN-gamma, or TNF-alpha. HMGB1 purified from cells grown in culture media alone only minimally increased cytokine production by MH-S macrophages and had no effect on murine neutrophils. In contrast, HMGB1 isolated from cells cultured in the presence of IL-1beta, IFN-gamma, and TNF-alpha had enhanced proinflammatory activity, resulting in increased production of MIP-2 and TNF-alpha by exposed cells. IL-1beta was bound to HMGB1 isolated from cells cultured with this cytokine, and purified HMGB1 incubated with recombinant IL-1beta acquired proinflammatory activity. Addition of anti-IL-1beta Abs or the IL-1 receptor antagonist to cell cultures blocked the proinflammatory activity of HMGB1 purified from IL-1beta-exposed cells, indicating that such activity was dependent on interaction with the IL-1 receptor. These results demonstrate that HMGB1 acquires proinflammatory activity through binding to proinflammatory mediators, such as IL-1beta.

A major ingredient of green tea rescues mice from lethal sepsis partly by inhibiting HMGB1.

BACKGROUND: The pathogenesis of sepsis is mediated in part by bacterial endotoxin, which stimulates macrophages/monocytes to sequentially release early (e.g., TNF, IL-1, and IFN-gamma) and late (e.g., HMGB1) pro-inflammatory cytokines. Our recent discovery of HMGB1 as a late mediator of lethal sepsis has prompted investigation for development of new experimental therapeutics. We previously reported that green tea brewed from the leaves of the plant Camellia sinensis is effective in inhibiting endotoxin-induced HMGB1 release. METHODS AND FINDINGS: Here we demonstrate that its major component, (-)-epigallocatechin-3-gallate (EGCG), but not catechin or ethyl gallate, dose-dependently abrogated HMGB1 release in macrophage/monocyte cultures, even when given 2-6 hours post LPS stimulation. Intraperitoneal administration of EGCG protected mice against lethal endotoxemia, and rescued mice from lethal sepsis even when the first dose was given 24 hours after cecal ligation and puncture. The therapeutic effects were partly attributable to: 1) attenuation of systemic accumulation of proinflammatory mediator (e.g., HMGB1) and surrogate marker (e.g., IL-6 and KC) of lethal sepsis; and 2) suppression of HMGB1-mediated inflammatory responses by preventing clustering of exogenous HMGB1 on macrophage cell surface. CONCLUSIONS: Taken together, these data suggest a novel mechanism by which the major green tea component, EGCG, protects against lethal endotoxemia and sepsis.