monorden and Sepsis

Intestinal injury is a key feature in sepsis. Inhibitors of heat shock protein 90 (Hsp90) have been shown to exert protective effects in models of inflammation. Herein, we hypothesized that Hsp90 might regulate intestinal inflammation and leakage in abdominal sepsis.. Male C57BL/6 mice were pretreated with radicicol (60 mg/kg), which is a specific inhibitor of Hsp90, prior to cecal ligation and puncture (CLP). Intravital fluorescence microscopy was used to quantify leukocyte-endothelium interactions in the colonic microcirculation 6 h after CLP. Colonic tissue was harvested to determine levels of myeloperoxidase, tumor necrosis factor-α and CXC chemokines. Intestinal injury was examined by histology. Intestinal barrier function was quantified by leakage of fluorescein isothiocyanate-dextran from the vascular system out into the abdominal cavity after intravenous injection.. We found that radicicol significantly decreased CLP-induced leukocyte rolling and adhesion in colonic venules. Inhibition of Hsp90 reduced colonic levels of myeloperoxidase by 24% in septic animals. Moreover, radicicol significantly decreased CLP-provoked formation of CXC chemokines but had no significant effect on tumor necrosis factor-α levels in the colon. Notably, Hsp90 inhibition significantly attenuated intestinal tissue injury evoked by CLP. Lastly, it was found that radicicol reduced sepsis-induced intestinal leakage by 43%.. Our novel findings suggest that targeting Hsp90 protects against intestinal inflammation and leakage and might be a useful strategy to ameliorate intestinal failure in polymicrobial sepsis.

Topics: Abdomen; Animals; Chemokine CXCL2; Colitis; HSP90 Heat-Shock Proteins; Leukocyte Rolling; Macrolides; Male; Mice; Mice, Inbred C57BL; Permeability; Sepsis

Severe sepsis is the leading cause of death for patients in intensive care units. Patients with severe sepsis develop multiple organ failure, including acute lung injury (ALI), resulting from a deregulated inflammatory response. Inhibitors of the ubiquitous chaperone, heat shock protein 90 (Hsp90), block the activity of certain proinflammatory mediators in vitro. We hypothesized that Hsp90 inhibitors may ameliorate the inflammation and ALI associated with severe sepsis.. To test the hypothesis that Hsp90 inhibitors prolong survival, attenuate inflammation, and reduce lung injury in a murine model of sepsis.. Male C57BL/6 mice received either one of two Hsp90 inhibitors, radicicol or 17-allylaminodemethoxygeldanamycin (17-AAG), 24, 12, 6, and 0 hours before receiving a lethal dose of endotoxin (6.75 x 10(4) endotoxin units/g body weight). Outcomes included survival and parameters of systemic inflammation (plasma neutrophil, cytokine, chemokine, and nitrite/nitrate levels), pulmonary inflammation (lung nuclear factor-kappaB and myeloperoxidase activities, inducible nitric oxide synthase expression, inducible nitric oxide synthase-Hsp90 complex formation, and leukocyte infiltration), and lung injury (pulmonary capillary leak and lung function).. Mice pretreated with vehicle and receiving endotoxin exhibited 100% 24-hour lethality, a dramatic increase in all parameters of systemic and pulmonary inflammation, increased capillary leak, and reduced lung function. Compared with them, mice receiving either radicicol or 17-AAG before endotoxin exhibited prolonged survival, reduced or abolished increases in systemic and pulmonary inflammatory parameters, attenuated capillary leak, and restored, normal lung function.. Hsp90 inhibitors may offer a new pharmacological tool in the management of severe sepsis and severe sepsis-induced ALI.

Topics: Animals; Benzoquinones; Chemokines; Cytokines; HSP90 Heat-Shock Proteins; Inflammation; Inflammation Mediators; Lactams, Macrocyclic; Lung; Macrolides; Male; Mice; Mice, Inbred C57BL; NF-kappa B; Nitrates; Nitric Oxide Synthase Type II; Nitrites; Peroxidase; Respiratory Distress Syndrome; Sepsis; Survival Rate

Sepsis accompanies myocardial dysfunction and dynamic alterations of cardiac metabolism. We have recently demonstrated that the very low-density lipoprotein receptor (VLDL-R), which is abundantly expressed in the heart, plays a key role in energy metabolism of the fasting heart. However, little is known about the function and regulation of the VLDL-R during sepsis. In the present study, we explored lipid accumulation and VLDL-R expression in the lipopolysaccharide (LPS)-stimulated heart in vivo and regulation of VLDL-R expression in vitro.. Electron microscopy and immunohistochemistry demonstrated that LPS significantly decreased both lipid accumulation and VLDL-R expression in the hearts of fasting mice. Treatment with LPS also downregulated VLDL-R in rat neonatal cardiac myocytes, and this downregulation was completely reversed by interleukin (IL)-1beta receptor antagonist. IL-1beta downregulated the expression of VLDL-R in a time- and dose-dependent manner and markedly reduced the uptake of DiI-labeled beta-VLDL but not DiI-labeled low-density lipoprotein (LDL). Use of specific pharmacologic inhibitors and short interference RNA revealed that Hsp90 was required for IL-1beta to downregulate VLDL-R expression.. These findings suggest that IL-1beta is a principle mediator of changes in cardiac lipid and energy metabolism during sepsis through the downregulation of myocardial VLDL-R expression.

Topics: Animals; Animals, Newborn; Cells, Cultured; Down-Regulation; Fasting; Female; HSP90 Heat-Shock Proteins; Humans; Immunoblotting; Interleukin-1; Lipid Metabolism; Macrolides; Mice; Mice, Inbred BALB C; Microscopy, Electron, Transmission; Myocardium; Myocytes, Cardiac; Rats; Rats, Sprague-Dawley; Receptors, LDL; Reverse Transcriptase Polymerase Chain Reaction; RNA, Small Interfering; Sepsis