We previously reported that increased production of prostaglandin E2 by monocytes is a pivotal me... more We previously reported that increased production of prostaglandin E2 by monocytes is a pivotal mechanism in posttrauma immunopathology. Here we characterize monocyte levels of transforming growth factor~ and examine the effects of elevated transforming growth factor~ on prostaglandin E2 release by patients' monocytes. Trauma patients' and normals' monocyte supernates (stimulation with muramyl dipeptide) were acid treated and assayed for transforming growth factor~ using the mink lung-cell bioassay. Alternatively, human transforming growth factor~ was added to patients' and normals' monocytes and prostaglandin E2 production assayed. Significantly elevated transforming growth factor~ levels (median = t81.7 pmol]10 6 monocytes) were detected in immunosuppressed patients' monocytes but not immunocompetent trauma patients' (median = 32,0 pM) or normats' (median = 20.4 pM) monocytes. Adding transforming growth factor~ to monocytes resulted in a significant elevation of prostaglandin E2 levels. Elevated monocyte transforming growth factor~ levels in trauma patients could be both suppressing T-lymphocyte functions and maintaining elevated monocyte prostaglandin E2 synthesis.
... on IL-4 levels is undetermined, murine data suggest that ethanol exposure could interfere wit... more ... on IL-4 levels is undetermined, murine data suggest that ethanol exposure could interfere with B cell activation by IL-4. Aldo-Benson et ... REFERENCES 1. Hill, DB, Marsano, L., Cohen, D., Allen, J., Shedlofsky, S., and McClain, C., Increased plasma interleukin-6 concentrations in ...
Background: Immunosuppression associated with chronic alcohol use is characterized by reduced ant... more Background: Immunosuppression associated with chronic alcohol use is characterized by reduced antigen-specific T-cell response and impaired delayed type hypersensitivity. Increasing evidence suggests in chronic alcohol consumption models that reduced antigen-specific T-cell proliferation is due to insufficient accessory cell function. Accessory cell function, a critical step in recognition of viral antigens, is reduced in chronic hepatitis C. The severity of hepatitis C is increased by alcohol consumption. Thus, we investigated the effects of alcohol consumption on accessory cell activity of monocytes in supporting alloreactive T-cell proliferation.
Alcoholism Clinical and Experimental Research, Oct 1, 1997
Acute ethanol exposure has the capacity to modulate immune functions, particularly, to down regul... more Acute ethanol exposure has the capacity to modulate immune functions, particularly, to down regulate monocyte production of inflammatory cytokines. However, the intracellular mechanisms for these effects of ethanol are yet to be understood. Considering that nuclear regulatory factor-rcp (NF-rcB)/Rel is a common regulatory element of the promoter region of the inflammatory cytokine genes, herein, we tested the hypothesis that acute ethanol affects NF-KB activation in human monocytes. Adherence-isolated monocytes showed constitutive DNA binding activity of NF-KB. A clinically relevant dose (25 mM) of acute ethanol treatment in vitro increased NF-KB binding activity in monocytes with a preferential induction of the inhibitory, p5o/p50, NF-KB/Rel homodimer, and resulted in no induction of the p65/p50 heterodimer. In contrast, lipopolysaccharide stimulation primarily induced the p65/psO heterodimer that has been shown to result in gene activation. Thus, such unique activation of the inhibitory p50/p50 homodimer by acute ethanol treatment may result in inhibition rather than activation of NF-&-regulated inflammatory cytokine genes. Consequently, these results suggest that physiologically relevant concentrations of ethanol may affect production of inflammatory cytokines, such as tumor necrosis factor-a, interleukin-ip, and interleukin-6 by disrupting NF-KB signaling in monocytes.
Ethanol consumption is associated with impaired immunity. Our data demonstrate that even a single... more Ethanol consumption is associated with impaired immunity. Our data demonstrate that even a single dose of a biologically relevant concentration (25-150 mM) of ethanol can down-regulate antigen-specific T lymphocyte proliferation. In contrast, ethanol augmented mitogen-induced T cell proliferation, suggesting that its inhibitory effect on antigen-specific T cell proliferation was due to its effects on monocytes (m phi s) rather than on T cells. The immunodepressive effects of ethanol on m phi antigen-presenting cell (APC) capacity were manifested whether alcohol treatment was limited to the antigen uptake-processing period only or was present during the entire period of antigen presentation. These inhibitory effects of ethanol were also evident on both the high-antigen-presenting, Fc gamma RI-negative (-31 +/- 17%), and low-antigen-presenting, Fc gamma RI-positive (-42 +/- 15%) m phi subpopulations. Further analysis demonstrated that ethanol inhibits the production of interleukin-1 beta (IL-1 beta) and induces transforming growth factor beta (TGF-beta) and prostaglandin E2 (PGE2), monocyte-derived mediators that can affect T cell proliferation. Ethanol resulted in a dose-dependent down-regulation of secreted and cell-associated IL-1 beta protein as well as IL-1 beta mRNA levels induced by adherence or bacterial stimulation. The causal relationship between decreased m phi IL-1 beta production, elevated TGF-beta levels, and the decreased m phi APC capacity was further substantiated when exogenous IL-1 beta protein or anti-TGF-beta neutralizing antibody prevented the down-regulatory effect of ethanol on antigen-specific T cell proliferation. Utilizing a cyclooxygenase inhibitor, we also demonstrated that the ethanol-induced decrease in m phi APCs is not mediated by enhanced PGE2 production.
Stimulation of monocytes (MO) through receptors for the Fc region of immunoglobulin G (Fc␥R) acti... more Stimulation of monocytes (MO) through receptors for the Fc region of immunoglobulin G (Fc␥R) activates a variety of responses, including phagocytosis, antibody (Ab)dependent cellular cytotoxicity, and production of cytokines. We previously reported that the MO subpopulation that expresses Fc␥R in high density produces high levels of tumor necrosis factor ␣ (TNF-␣) compared with Fc␥R-negative MO. Here, we show that cross-linking MO via
Chronic alcohol causes hepatic steatosis and liver hypoxia. Hypoxia-regulated Hypoxia-inducible f... more Chronic alcohol causes hepatic steatosis and liver hypoxia. Hypoxia-regulated Hypoxia-inducible factor 1-α, (HIF1α) may regulate liporegulatory genes but the relationship of HIF1 to steatosis remains unknown. We investigated HIF1α in alcohol-induced hepatic lipid accumulation. Alcohol administration resulted in steatosis, increased liver triglyceride levels and serum ALT suggesting liver injury in WT mice. There was increased hepatic HIF1α mRNA, protein and DNA-binding activity in alcohol-fed mice compared to controls. Mice engineered with hepatocyte-specific HIF1 activation (HIF1dPA) had increased HIF1α mRNA, protein, and DNA-binding activity, and alcohol feeding in HIF1dPA mice increased hepatomegaly and hepatic triglyceride compared to WT. In contrast, hepatocyte-specific deletion of HIF1α (HIF-1α(Hep-/-), protected mice from alcohol-and LPS-induced liver damage, serum ALT elevation, hepatomegaly and lipid accumulation. HIF-1α(Hep-/-), WT, and HIF1dPA mice had equally suppressed levels of PPARα mRNA after chronic ethanol, while the HIF target, ADRP, was upregulated in WT, but not in HIF-1α(Hep-/-) ethanol fed/LPS challenged mice. The chemokine, MCP-1, was cooperatively induced by alcohol feeding and LPS in WT but not in HIF-1α(Hep-/-) mice. Using Huh7 hepatoma cells in vitro, we found that MCP-1 treatment induced lipid accumulation and increased HIF1α protein expression as well as DNA-binding activity. SiRNA inhibition of HIF1α prevented MCP-1-induced lipid accumulation suggesting a mechanistic role for HIF1α in hepatocyte lipid accumulation.
The hypothesis that acute ethanol uptake plus trauma can synergize to increase immunosuppression ... more The hypothesis that acute ethanol uptake plus trauma can synergize to increase immunosuppression was tested. We found that, unlike non-alcohol-exposed patients, patients with acute alcohol use prior to trauma have a transient decrease in monocyte tumor necrosis factor alpha (TNF alpha) production during the very early postinjury (0-3 days) period. However, TNF alpha production by these alcohol-exposed patients' monocytes (M0) became hyperelevated late postinjury (> 9 days). Consequently, these massively elevated M0 TNF alpha levels can contribute to posttrauma immunosuppression after acute alcohol use. We also demonstrate that normal monocyte activation with the superantigen, Staphylococcus enterotoxin B (SEB), results in a preferential induction of cell-associated M0 TNF alpha production, described as characteristic of immunosuppressed trauma patients. Acute in vitro ethanol treatment down-regulated the elevated TNF alpha production by trauma patients' M0 after either SEB, muramyl-dipeptide (MDP), interferon-gamma plus MDP, or lipopolysaccharide (LPS) stimulation. Both SEB- and LPS-induced TNF alpha mRNA induction was inhibited by acute alcohol treatment in normal M0, indicating that ethanol can regulate cytokine gene expression. An additional immunosuppressive effect of acute ethanol's stimulation was suggested by its induction of elevated transforming growth factor beta production in trauma patients' activated M0.
To test our hypothesis that monocytes (M phi) and their mediators are major contributors to ethan... more To test our hypothesis that monocytes (M phi) and their mediators are major contributors to ethanol-related immunodepression, the modulating capacity of acute ethanol treatment was assessed on the production of transforming growth factor-beta (TGF beta) and prostaglandin E2 (PGE2) by human peripheral blood M phi. We demonstrate that acute in vitro treatment of adherent M phi with either 50 or 150 mM ethanol induced a significant increase in the production of TGF beta (P < 0.045 and P < 0.001, respectively). Furthermore, M phi pretreatment with both 50 and 150 mM ethanol augmented TGF beta production in response to subsequent stimulation with the synthetic bacterial analog, muramyl dipeptide (MDP) (P < 0.05 and P < 0.001, respectively). Ethanol also increased TGF beta production in interferon gamma (IFN gamma-activated M phi in response to MDP stimulus (P < 0.05). M phi TGF beta levels, however, were always lower in IFN gamma-activated than in non-IFN gamma-activated M phi after the same stimulation with ethanol plus MDP, suggesting that M phi preactivation by IFN gamma can partially counteract the TGF beta inducing potential of ethanol. Similar to its TGF beta-inducing potential, ethanol (150 mM) had the capacity to induce PGE2 production in adherent human M phi (P < 0.045). However, ethanol failed to augment M phi PGE2 production induced by the PGE2 secretagogue, MDP. TGF beta induction by ethanol was unaffected by the presence of cyclooxygenase inhibitor, suggesting that ethanol-induced M phi TGF beta production does not require M phi PGE2 production. These results indicate that ethanol is a potent inducer for inhibitory M phi mediators, TGF beta and PGE2, and also has the capacity to augment M phi TGF beta production in response to subsequent stimulation. Thus, ethanol-induced elevation of M phi TGF beta and PGE2 production might contribute to decreased T cell proliferation and abnormal M phi functions after alcohol exposure, resulting in a depressed immune response.
Immunomodulatory effects of alcohol use involve regulation of innate immune cell function leading... more Immunomodulatory effects of alcohol use involve regulation of innate immune cell function leading to liver disease. Alteration of inflammatory responses by alcohol is linked to dysregulated TNF-alpha production. Alcohol-induced oxidative stress also contributes to alterations in inflammatory cell activity. Heat shock proteins (hsps) and the heat shock transcription factor-1 (HSF-1) induced by oxidative stress regulate NF-kappaB activation and TNF-alpha gene expression in monocytes and macrophages. Here, we report that in vitro alcohol treatment induced and augmented LPS-induced HSF-1 nuclear translocation and DNA-binding activity in monocytes and macrophages. Supershift analysis revealed that alcohol regulated HSF-1- and not HSF-2-binding activity. Hsp70, a target gene induced by HSF-1, was transiently increased within 24 h by alcohol, but extended alcohol exposure decreased hsp70 in macrophages. The alcohol-induced alteration of hsp70 correlated with a concomitant change in hsp70 promoter activity. Hsp90, another HSF-1 target gene, was decreased during short-term alcohol but increased after prolonged alcohol exposure. Decreased hsp90-HSF-1 complexes after short-term alcohol indicated dissociation of HSF-1 from hsp90. On the other hand, hsp90 interacted with client protein IkappaB kinase beta, a signaling intermediate of the LPS pathway, followed by IkappaBalpha degradation and increased NF-kappaB activity after chronic alcohol exposure, indicating that hsp90 plays an important role in supporting inflammatory cytokine production. Inhibition of hsp90 using geldanamycin prevented prolonged alcohol-induced elevation in LPS-induced NF-kappaB and TNF-alpha production. These results suggest that alcohol exposure differentially regulates hsp70 and hsp90 via HSF-1 activation. Further, hsp90 regulates TNF-alpha production in macrophages contributing to alcohol-induced inflammation.
Alcoholism Clinical and Experimental Research, 2002
Background: Immunosuppression associated with chronic alcohol use is characterized by reduced ant... more Background: Immunosuppression associated with chronic alcohol use is characterized by reduced antigen-specific T-cell response and impaired delayed type hypersensitivity. Increasing evidence suggests in chronic alcohol consumption models that reduced antigen-specific T-cell proliferation is due to insufficient accessory cell function. Accessory cell function, a critical step in recognition of viral antigens, is reduced in chronic hepatitis C. The severity of hepatitis C is increased by alcohol consumption. Thus, we investigated the effects of alcohol consumption on accessory cell activity of monocytes in supporting alloreactive T-cell proliferation.
Alcoholism Clinical and Experimental Research, Sep 1, 1996
We and others have previously shown that even acute ethanol exposure has the capacity to modulate... more We and others have previously shown that even acute ethanol exposure has the capacity to modulate immune functions, particularly monocyte functions. Herein, we tested the hypothesis that acute ethanol treatment inhibits inflammatory, while increasing inhibitory cytokine production in human blood monocytes that, in tum, could contribute to the overall immune abnormalities seen after alcohol use. Our data show that in vitro treatment of blood monocytes with a physiologically relevant dose of alcohol (W mM) results in significantly decreased induction of tumor necrosis factor-a (TNFa) and interleukin (IL)-l p by bacterial stimulation of either Gram-positive [staphylococcal enterotoxin B (SEB), 1 pg/ml of SEB] or Gram-negative [lipopolysaccharide (LPS), 1 pg/ml of LPS] origin both at the protein and mRNA levels. In contrast, acute ethanol treatment induces monocyte production of mediators with immunoinhibitory potential, including transforming growth factor-p and IL-10. We further show that ethanol not only induces monocyte/macrophage ( M 0 ) IL-10 and transforming growth factor-p, but even augments bacterial (both LPS and SEB) stimulation-induced production of both of these cytokines. IL-10 is a potent inhibitor of M 0 TNFa production. We found that ethanol-induced elevation in M 0 IL-10 levels contributes to the decreased M 0 TNFa production to bacterial challenge in ethanol-exposed M 0 . However, mRNA levels for TNFa are downregulated as early as 1.5 hr after ethanol treatment, suggesting that ethanol likely has an IL-10 independent, direct effect on early signaling events of TNFa induction.
We previously reported that increased production of prostaglandin E2 by monocytes is a pivotal me... more We previously reported that increased production of prostaglandin E2 by monocytes is a pivotal mechanism in posttrauma immunopathology. Here we characterize monocyte levels of transforming growth factor~ and examine the effects of elevated transforming growth factor~ on prostaglandin E2 release by patients' monocytes. Trauma patients' and normals' monocyte supernates (stimulation with muramyl dipeptide) were acid treated and assayed for transforming growth factor~ using the mink lung-cell bioassay. Alternatively, human transforming growth factor~ was added to patients' and normals' monocytes and prostaglandin E2 production assayed. Significantly elevated transforming growth factor~ levels (median = t81.7 pmol]10 6 monocytes) were detected in immunosuppressed patients' monocytes but not immunocompetent trauma patients' (median = 32,0 pM) or normats' (median = 20.4 pM) monocytes. Adding transforming growth factor~ to monocytes resulted in a significant elevation of prostaglandin E2 levels. Elevated monocyte transforming growth factor~ levels in trauma patients could be both suppressing T-lymphocyte functions and maintaining elevated monocyte prostaglandin E2 synthesis.
Alcoholic liver disease (ALD) ranges from fatty liver to inflammation and cirrhosis. miRNA-155 is... more Alcoholic liver disease (ALD) ranges from fatty liver to inflammation and cirrhosis. miRNA-155 is an important regulator of inflammation. In this study, we describe the in vivo role of miR-155 in ALD. Wild type, WT (C57/BL6J) or miR-155 KO and TLR4 KO mice received Lieber-DeCarli diet for 5 weeks. Some mice received corn oil or CCl4 for 2 or 9 weeks. We found that miR-155 KO mice are protected from alcohol-induced steatosis and inflammation. The reduction in alcohol-induced fat accumulation in miR-155 KO mice was associated with increased PPRE and PPARα (miR-155 target) binding and decreased MCP1 production. Treatment with a miR-155 inhibitor increased PPARγ expression in naive and alcohol treated RAW macrophages. Alcohol increased lipid metabolism genes (FABP4, LXRα, ACC1 and LDLR) in WT mice and this was prevented in KO mice. Alcohol diet induced increase in the number of CD163(+)CD206(+) infiltrating macrophages and neutrophils in WT was prevented in miR-155 KO mice. Kupffer cells isolated from miR-155 KO mice exhibited predominance of M2 phenotype when exposed to M1 polarized signals and this was due to increased C/EBPβ. Profibrotic genes were attenuated in miR-155 KO mice after alcohol diet or CCl4 treatment. Compared to WT attenuation in CCl4 induced hydroxyproline and α SMA was observed in KO mice. Finally, we show TLR4 signaling regulates miR-155 as TLR4 KO mice showed no induction of miR-155 after alcohol diet. Collectively our results demonstrated the role of miR-155 in alcohol-induced steatohepatitis and fibrosis in vivo.
We previously reported that increased production of prostaglandin E2 by monocytes is a pivotal me... more We previously reported that increased production of prostaglandin E2 by monocytes is a pivotal mechanism in posttrauma immunopathology. Here we characterize monocyte levels of transforming growth factor~ and examine the effects of elevated transforming growth factor~ on prostaglandin E2 release by patients' monocytes. Trauma patients' and normals' monocyte supernates (stimulation with muramyl dipeptide) were acid treated and assayed for transforming growth factor~ using the mink lung-cell bioassay. Alternatively, human transforming growth factor~ was added to patients' and normals' monocytes and prostaglandin E2 production assayed. Significantly elevated transforming growth factor~ levels (median = t81.7 pmol]10 6 monocytes) were detected in immunosuppressed patients' monocytes but not immunocompetent trauma patients' (median = 32,0 pM) or normats' (median = 20.4 pM) monocytes. Adding transforming growth factor~ to monocytes resulted in a significant elevation of prostaglandin E2 levels. Elevated monocyte transforming growth factor~ levels in trauma patients could be both suppressing T-lymphocyte functions and maintaining elevated monocyte prostaglandin E2 synthesis.
... on IL-4 levels is undetermined, murine data suggest that ethanol exposure could interfere wit... more ... on IL-4 levels is undetermined, murine data suggest that ethanol exposure could interfere with B cell activation by IL-4. Aldo-Benson et ... REFERENCES 1. Hill, DB, Marsano, L., Cohen, D., Allen, J., Shedlofsky, S., and McClain, C., Increased plasma interleukin-6 concentrations in ...
Background: Immunosuppression associated with chronic alcohol use is characterized by reduced ant... more Background: Immunosuppression associated with chronic alcohol use is characterized by reduced antigen-specific T-cell response and impaired delayed type hypersensitivity. Increasing evidence suggests in chronic alcohol consumption models that reduced antigen-specific T-cell proliferation is due to insufficient accessory cell function. Accessory cell function, a critical step in recognition of viral antigens, is reduced in chronic hepatitis C. The severity of hepatitis C is increased by alcohol consumption. Thus, we investigated the effects of alcohol consumption on accessory cell activity of monocytes in supporting alloreactive T-cell proliferation.
Alcoholism Clinical and Experimental Research, Oct 1, 1997
Acute ethanol exposure has the capacity to modulate immune functions, particularly, to down regul... more Acute ethanol exposure has the capacity to modulate immune functions, particularly, to down regulate monocyte production of inflammatory cytokines. However, the intracellular mechanisms for these effects of ethanol are yet to be understood. Considering that nuclear regulatory factor-rcp (NF-rcB)/Rel is a common regulatory element of the promoter region of the inflammatory cytokine genes, herein, we tested the hypothesis that acute ethanol affects NF-KB activation in human monocytes. Adherence-isolated monocytes showed constitutive DNA binding activity of NF-KB. A clinically relevant dose (25 mM) of acute ethanol treatment in vitro increased NF-KB binding activity in monocytes with a preferential induction of the inhibitory, p5o/p50, NF-KB/Rel homodimer, and resulted in no induction of the p65/p50 heterodimer. In contrast, lipopolysaccharide stimulation primarily induced the p65/psO heterodimer that has been shown to result in gene activation. Thus, such unique activation of the inhibitory p50/p50 homodimer by acute ethanol treatment may result in inhibition rather than activation of NF-&-regulated inflammatory cytokine genes. Consequently, these results suggest that physiologically relevant concentrations of ethanol may affect production of inflammatory cytokines, such as tumor necrosis factor-a, interleukin-ip, and interleukin-6 by disrupting NF-KB signaling in monocytes.
Ethanol consumption is associated with impaired immunity. Our data demonstrate that even a single... more Ethanol consumption is associated with impaired immunity. Our data demonstrate that even a single dose of a biologically relevant concentration (25-150 mM) of ethanol can down-regulate antigen-specific T lymphocyte proliferation. In contrast, ethanol augmented mitogen-induced T cell proliferation, suggesting that its inhibitory effect on antigen-specific T cell proliferation was due to its effects on monocytes (m phi s) rather than on T cells. The immunodepressive effects of ethanol on m phi antigen-presenting cell (APC) capacity were manifested whether alcohol treatment was limited to the antigen uptake-processing period only or was present during the entire period of antigen presentation. These inhibitory effects of ethanol were also evident on both the high-antigen-presenting, Fc gamma RI-negative (-31 +/- 17%), and low-antigen-presenting, Fc gamma RI-positive (-42 +/- 15%) m phi subpopulations. Further analysis demonstrated that ethanol inhibits the production of interleukin-1 beta (IL-1 beta) and induces transforming growth factor beta (TGF-beta) and prostaglandin E2 (PGE2), monocyte-derived mediators that can affect T cell proliferation. Ethanol resulted in a dose-dependent down-regulation of secreted and cell-associated IL-1 beta protein as well as IL-1 beta mRNA levels induced by adherence or bacterial stimulation. The causal relationship between decreased m phi IL-1 beta production, elevated TGF-beta levels, and the decreased m phi APC capacity was further substantiated when exogenous IL-1 beta protein or anti-TGF-beta neutralizing antibody prevented the down-regulatory effect of ethanol on antigen-specific T cell proliferation. Utilizing a cyclooxygenase inhibitor, we also demonstrated that the ethanol-induced decrease in m phi APCs is not mediated by enhanced PGE2 production.
Stimulation of monocytes (MO) through receptors for the Fc region of immunoglobulin G (Fc␥R) acti... more Stimulation of monocytes (MO) through receptors for the Fc region of immunoglobulin G (Fc␥R) activates a variety of responses, including phagocytosis, antibody (Ab)dependent cellular cytotoxicity, and production of cytokines. We previously reported that the MO subpopulation that expresses Fc␥R in high density produces high levels of tumor necrosis factor ␣ (TNF-␣) compared with Fc␥R-negative MO. Here, we show that cross-linking MO via
Chronic alcohol causes hepatic steatosis and liver hypoxia. Hypoxia-regulated Hypoxia-inducible f... more Chronic alcohol causes hepatic steatosis and liver hypoxia. Hypoxia-regulated Hypoxia-inducible factor 1-α, (HIF1α) may regulate liporegulatory genes but the relationship of HIF1 to steatosis remains unknown. We investigated HIF1α in alcohol-induced hepatic lipid accumulation. Alcohol administration resulted in steatosis, increased liver triglyceride levels and serum ALT suggesting liver injury in WT mice. There was increased hepatic HIF1α mRNA, protein and DNA-binding activity in alcohol-fed mice compared to controls. Mice engineered with hepatocyte-specific HIF1 activation (HIF1dPA) had increased HIF1α mRNA, protein, and DNA-binding activity, and alcohol feeding in HIF1dPA mice increased hepatomegaly and hepatic triglyceride compared to WT. In contrast, hepatocyte-specific deletion of HIF1α (HIF-1α(Hep-/-), protected mice from alcohol-and LPS-induced liver damage, serum ALT elevation, hepatomegaly and lipid accumulation. HIF-1α(Hep-/-), WT, and HIF1dPA mice had equally suppressed levels of PPARα mRNA after chronic ethanol, while the HIF target, ADRP, was upregulated in WT, but not in HIF-1α(Hep-/-) ethanol fed/LPS challenged mice. The chemokine, MCP-1, was cooperatively induced by alcohol feeding and LPS in WT but not in HIF-1α(Hep-/-) mice. Using Huh7 hepatoma cells in vitro, we found that MCP-1 treatment induced lipid accumulation and increased HIF1α protein expression as well as DNA-binding activity. SiRNA inhibition of HIF1α prevented MCP-1-induced lipid accumulation suggesting a mechanistic role for HIF1α in hepatocyte lipid accumulation.
The hypothesis that acute ethanol uptake plus trauma can synergize to increase immunosuppression ... more The hypothesis that acute ethanol uptake plus trauma can synergize to increase immunosuppression was tested. We found that, unlike non-alcohol-exposed patients, patients with acute alcohol use prior to trauma have a transient decrease in monocyte tumor necrosis factor alpha (TNF alpha) production during the very early postinjury (0-3 days) period. However, TNF alpha production by these alcohol-exposed patients' monocytes (M0) became hyperelevated late postinjury (> 9 days). Consequently, these massively elevated M0 TNF alpha levels can contribute to posttrauma immunosuppression after acute alcohol use. We also demonstrate that normal monocyte activation with the superantigen, Staphylococcus enterotoxin B (SEB), results in a preferential induction of cell-associated M0 TNF alpha production, described as characteristic of immunosuppressed trauma patients. Acute in vitro ethanol treatment down-regulated the elevated TNF alpha production by trauma patients' M0 after either SEB, muramyl-dipeptide (MDP), interferon-gamma plus MDP, or lipopolysaccharide (LPS) stimulation. Both SEB- and LPS-induced TNF alpha mRNA induction was inhibited by acute alcohol treatment in normal M0, indicating that ethanol can regulate cytokine gene expression. An additional immunosuppressive effect of acute ethanol's stimulation was suggested by its induction of elevated transforming growth factor beta production in trauma patients' activated M0.
To test our hypothesis that monocytes (M phi) and their mediators are major contributors to ethan... more To test our hypothesis that monocytes (M phi) and their mediators are major contributors to ethanol-related immunodepression, the modulating capacity of acute ethanol treatment was assessed on the production of transforming growth factor-beta (TGF beta) and prostaglandin E2 (PGE2) by human peripheral blood M phi. We demonstrate that acute in vitro treatment of adherent M phi with either 50 or 150 mM ethanol induced a significant increase in the production of TGF beta (P < 0.045 and P < 0.001, respectively). Furthermore, M phi pretreatment with both 50 and 150 mM ethanol augmented TGF beta production in response to subsequent stimulation with the synthetic bacterial analog, muramyl dipeptide (MDP) (P < 0.05 and P < 0.001, respectively). Ethanol also increased TGF beta production in interferon gamma (IFN gamma-activated M phi in response to MDP stimulus (P < 0.05). M phi TGF beta levels, however, were always lower in IFN gamma-activated than in non-IFN gamma-activated M phi after the same stimulation with ethanol plus MDP, suggesting that M phi preactivation by IFN gamma can partially counteract the TGF beta inducing potential of ethanol. Similar to its TGF beta-inducing potential, ethanol (150 mM) had the capacity to induce PGE2 production in adherent human M phi (P < 0.045). However, ethanol failed to augment M phi PGE2 production induced by the PGE2 secretagogue, MDP. TGF beta induction by ethanol was unaffected by the presence of cyclooxygenase inhibitor, suggesting that ethanol-induced M phi TGF beta production does not require M phi PGE2 production. These results indicate that ethanol is a potent inducer for inhibitory M phi mediators, TGF beta and PGE2, and also has the capacity to augment M phi TGF beta production in response to subsequent stimulation. Thus, ethanol-induced elevation of M phi TGF beta and PGE2 production might contribute to decreased T cell proliferation and abnormal M phi functions after alcohol exposure, resulting in a depressed immune response.
Immunomodulatory effects of alcohol use involve regulation of innate immune cell function leading... more Immunomodulatory effects of alcohol use involve regulation of innate immune cell function leading to liver disease. Alteration of inflammatory responses by alcohol is linked to dysregulated TNF-alpha production. Alcohol-induced oxidative stress also contributes to alterations in inflammatory cell activity. Heat shock proteins (hsps) and the heat shock transcription factor-1 (HSF-1) induced by oxidative stress regulate NF-kappaB activation and TNF-alpha gene expression in monocytes and macrophages. Here, we report that in vitro alcohol treatment induced and augmented LPS-induced HSF-1 nuclear translocation and DNA-binding activity in monocytes and macrophages. Supershift analysis revealed that alcohol regulated HSF-1- and not HSF-2-binding activity. Hsp70, a target gene induced by HSF-1, was transiently increased within 24 h by alcohol, but extended alcohol exposure decreased hsp70 in macrophages. The alcohol-induced alteration of hsp70 correlated with a concomitant change in hsp70 promoter activity. Hsp90, another HSF-1 target gene, was decreased during short-term alcohol but increased after prolonged alcohol exposure. Decreased hsp90-HSF-1 complexes after short-term alcohol indicated dissociation of HSF-1 from hsp90. On the other hand, hsp90 interacted with client protein IkappaB kinase beta, a signaling intermediate of the LPS pathway, followed by IkappaBalpha degradation and increased NF-kappaB activity after chronic alcohol exposure, indicating that hsp90 plays an important role in supporting inflammatory cytokine production. Inhibition of hsp90 using geldanamycin prevented prolonged alcohol-induced elevation in LPS-induced NF-kappaB and TNF-alpha production. These results suggest that alcohol exposure differentially regulates hsp70 and hsp90 via HSF-1 activation. Further, hsp90 regulates TNF-alpha production in macrophages contributing to alcohol-induced inflammation.
Alcoholism Clinical and Experimental Research, 2002
Background: Immunosuppression associated with chronic alcohol use is characterized by reduced ant... more Background: Immunosuppression associated with chronic alcohol use is characterized by reduced antigen-specific T-cell response and impaired delayed type hypersensitivity. Increasing evidence suggests in chronic alcohol consumption models that reduced antigen-specific T-cell proliferation is due to insufficient accessory cell function. Accessory cell function, a critical step in recognition of viral antigens, is reduced in chronic hepatitis C. The severity of hepatitis C is increased by alcohol consumption. Thus, we investigated the effects of alcohol consumption on accessory cell activity of monocytes in supporting alloreactive T-cell proliferation.
Alcoholism Clinical and Experimental Research, Sep 1, 1996
We and others have previously shown that even acute ethanol exposure has the capacity to modulate... more We and others have previously shown that even acute ethanol exposure has the capacity to modulate immune functions, particularly monocyte functions. Herein, we tested the hypothesis that acute ethanol treatment inhibits inflammatory, while increasing inhibitory cytokine production in human blood monocytes that, in tum, could contribute to the overall immune abnormalities seen after alcohol use. Our data show that in vitro treatment of blood monocytes with a physiologically relevant dose of alcohol (W mM) results in significantly decreased induction of tumor necrosis factor-a (TNFa) and interleukin (IL)-l p by bacterial stimulation of either Gram-positive [staphylococcal enterotoxin B (SEB), 1 pg/ml of SEB] or Gram-negative [lipopolysaccharide (LPS), 1 pg/ml of LPS] origin both at the protein and mRNA levels. In contrast, acute ethanol treatment induces monocyte production of mediators with immunoinhibitory potential, including transforming growth factor-p and IL-10. We further show that ethanol not only induces monocyte/macrophage ( M 0 ) IL-10 and transforming growth factor-p, but even augments bacterial (both LPS and SEB) stimulation-induced production of both of these cytokines. IL-10 is a potent inhibitor of M 0 TNFa production. We found that ethanol-induced elevation in M 0 IL-10 levels contributes to the decreased M 0 TNFa production to bacterial challenge in ethanol-exposed M 0 . However, mRNA levels for TNFa are downregulated as early as 1.5 hr after ethanol treatment, suggesting that ethanol likely has an IL-10 independent, direct effect on early signaling events of TNFa induction.
We previously reported that increased production of prostaglandin E2 by monocytes is a pivotal me... more We previously reported that increased production of prostaglandin E2 by monocytes is a pivotal mechanism in posttrauma immunopathology. Here we characterize monocyte levels of transforming growth factor~ and examine the effects of elevated transforming growth factor~ on prostaglandin E2 release by patients' monocytes. Trauma patients' and normals' monocyte supernates (stimulation with muramyl dipeptide) were acid treated and assayed for transforming growth factor~ using the mink lung-cell bioassay. Alternatively, human transforming growth factor~ was added to patients' and normals' monocytes and prostaglandin E2 production assayed. Significantly elevated transforming growth factor~ levels (median = t81.7 pmol]10 6 monocytes) were detected in immunosuppressed patients' monocytes but not immunocompetent trauma patients' (median = 32,0 pM) or normats' (median = 20.4 pM) monocytes. Adding transforming growth factor~ to monocytes resulted in a significant elevation of prostaglandin E2 levels. Elevated monocyte transforming growth factor~ levels in trauma patients could be both suppressing T-lymphocyte functions and maintaining elevated monocyte prostaglandin E2 synthesis.
Alcoholic liver disease (ALD) ranges from fatty liver to inflammation and cirrhosis. miRNA-155 is... more Alcoholic liver disease (ALD) ranges from fatty liver to inflammation and cirrhosis. miRNA-155 is an important regulator of inflammation. In this study, we describe the in vivo role of miR-155 in ALD. Wild type, WT (C57/BL6J) or miR-155 KO and TLR4 KO mice received Lieber-DeCarli diet for 5 weeks. Some mice received corn oil or CCl4 for 2 or 9 weeks. We found that miR-155 KO mice are protected from alcohol-induced steatosis and inflammation. The reduction in alcohol-induced fat accumulation in miR-155 KO mice was associated with increased PPRE and PPARα (miR-155 target) binding and decreased MCP1 production. Treatment with a miR-155 inhibitor increased PPARγ expression in naive and alcohol treated RAW macrophages. Alcohol increased lipid metabolism genes (FABP4, LXRα, ACC1 and LDLR) in WT mice and this was prevented in KO mice. Alcohol diet induced increase in the number of CD163(+)CD206(+) infiltrating macrophages and neutrophils in WT was prevented in miR-155 KO mice. Kupffer cells isolated from miR-155 KO mice exhibited predominance of M2 phenotype when exposed to M1 polarized signals and this was due to increased C/EBPβ. Profibrotic genes were attenuated in miR-155 KO mice after alcohol diet or CCl4 treatment. Compared to WT attenuation in CCl4 induced hydroxyproline and α SMA was observed in KO mice. Finally, we show TLR4 signaling regulates miR-155 as TLR4 KO mice showed no induction of miR-155 after alcohol diet. Collectively our results demonstrated the role of miR-155 in alcohol-induced steatohepatitis and fibrosis in vivo.
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