The human pathogen Candida albicans encodes at least three putative two-component histidine kinase signal transduction proteins, including Chk1p and a response regulator protein (Cssk1p). Strains deleted in CHK1 are avirulent in a murine model of hematogenously disseminated disease. The specific function of Chk1p has not been established, but hyphae of the chk1 mutant exhibit extensive flocculation while yeast forms are less adherent to reconstituted human esophageal tissue, indicating that this protein may regulate cell surface properties. Herein, we analyze glucan, mannan and chitin profiles in strains deleted in chk1 (CHK21) compared to a gene-reconstituted strain (CHK23) and a parental strain CAF2. Total alkali-soluble hexose from the cell wall of the chk1 mutant (strain CHK21) was significantly reduced. Western blots of cell wall extracts from CHK21, CHK23 and CAF2 reacted with a Mab to the acid-stable mannan fraction revealed extensive staining of lower molecular mass species in strain CHK21 only. FACE (fluorophore assisted carbohydrate electrophoresis) was used to characterize the oligosaccharide side chains of β-eliminated (O-linked), acid-hydrolyzed (acid-labile phosphomannan) and acetolysis (acid-stable mannan) extracted fractions of total mannan. The profiles of O-linked as well as the acid-labile oligosaccharides were similar in both CAF2 and CHK21, but the acid-stable oligosaccharide side chains were significantly truncated. We also characterized the β-glucan from each strain using NMR, and found that both the degree of polymerization and the ratio of (1-3)/(1-6) linkages was lower in CHK21 relative to wild-type cells. The sensitivity of CHK21 to antifungal drugs and inhibitors was unaffected. In summary, our data have identified a new function for a histidine kinase two-component signal protein in a human pathogenic fungus.

No description available.

The role of Group IVA cytosolic phospholipase A2 (cPLA2α) activation in regulating macrophage transcriptional responses to Candida albicans infection was investigated. cPLA2α releases arachidonic acid for the production of eicosanoids. In mouse resident peritoneal macrophages, prostacyclin, prostaglandin E2 and leukotriene C4 were produced within minutes of C. albicans addition before cyclooxygenase 2 expression. The production of TNFα was lower in C. albicans-stimulated cPLA2α+/+ than cPLA2α-/- macrophages due to an autocrine effect of prostaglandins that increased cAMP to a greater extent in cPLA2α+/+ than cPLA2α-/- macrophages. For global insight, differential gene expression in C. albicans-stimulated cPLA2α+/+ and cPLA2α-/- macrophages (3 h) was compared by microarray. cPLA2α+/+ macrophages expressed 86 genes at lower levels and 181 genes at higher levels than cPLA2α-/- macrophages (≥2-fold, p<0.05). Several pro-inflammatory genes were expressed at lower levels (Tnfα, Cx3cl1, Cd40, Ccl5, Csf1, Edn1, CxCr7, Irf1, Irf4, Akna, Ifnγ, several IFNγ-inducible GTPases). Genes that dampen inflammation (Socs3, Il10, Crem, Stat3, Thbd, Thbs1, Abca1) and genes involved in host defense (Gja1, Csf3, Trem1, Hdc) were expressed at higher levels in cPLA2α+/+ macrophages. Representative genes expressed lower in cPLA2α+/+ macrophages (Tnfα, Csf1) were increased by treatment with a prostacyclin receptor antagonist and protein kinase A inhibitor, whereas genes expressed at higher levels (Crem, Nr4a2, Il10, Csf3) were suppressed. The results suggest that C. albicans stimulates an autocrine loop in macrophages involving cPLA2α, cyclooxygenase 1-derived prostaglandins and increased cAMP that globally effects expression of genes involved in host defense and inflammation.

The immune system is essential to maintain homeostasis with resident microbial populations, ensuring that the symbiotic host-microbial relationship is maintained. In parallel, commensal microbes significantly shape mammalian immunity at the host mucosal surface, as well as systemically. Candida albicans is an opportunistic pathogen that lives as a commensal on skin and mucosa of healthy individuals. Little is known about its capacity to modulate responses toward other microorganisms, such as colonizing bacteria (e.g., intestinal microorganisms). The aim of this study was to assess the cytokine production of PBMCs induced by commensal bacteria when these cells were primed by C. albicans. We show that C. albicans and β-1,3-glucan induce priming of human primary mononuclear cells and this leads to enhanced cytokine production upon in vitro stimulation with TLR ligands and bacterial commensals. This priming requires the β-1,3-glucan receptor dectin-1 and the noncanonical Raf-1 pathway. In addition, although purified mannans cannot solely mediate the priming, the presence of mannosyl residues in the cell wall of C. albicans is nevertheless required. In conclusion, C. albicans is able to modify cytokine responses to TLR ligands and colonizing bacteria, which is likely to impact the inflammatory reaction during mucosal diseases.

Engagement of the innate immune system and activation of inflammatory responses have been demonstrated to play an important role in myocardial ischemia/reperfusion (I/R) injury (Barry 1994; Bryant et al. 1998; Frangogiannis 2006; Kubota et al. 1997) and congestive heart failure (CHF) (Torre-Amione et al. 1996). Experimental studies and clinical investigations have shown that I/R significantly increases myocardial inflammatory cytokine expression including TNF-α, IL-1β, IL-6, IL-8, interferon-γ (IFN-γ), and intercellular adhesion molecule-1 (I-CAM-1) (Barry 1994; Bryant et al. 1998; Frangogiannis 2006; Kubota et al. 1997; Kukielka et al. 1995). These proinflammatory cytokines are directly involved in the progression of myocardial I/R injury, myocardial dysfunction, vascular wall remodeling, and heart failure (Kelly and Smith 1997; Ono et al. 1998). However, we still do not fully understand the mechanisms by which the innate immune and inflammatory responses are involved in ischemic heart diseases.

This report concerns two cases and a review of the literature on the subject of symmetrical peripheral gangrene. Symmetrical peripheral gangrene is defined as symmetrical distal ischemic damage in two or more sites in the absence of major vascular occlusive disease. It occurs in patients who are septic and have disseminated intravascular coagulation and in nonseptic patients who have cardiogenic or hypovolemic shock. The syndrome is devastating and rare, and controlled studies of its etiology and management are lacking. Recommendations are presented for its prevention and treatment. Cooperative multicenter studies may be necessary to obtain valid data about its prevention and management.

Nuclear factor-κB (NF-κB) has been demonstrated to regulate the transcription of target genes and stimulate inflammatory cytokine responses in a variety of inflammatory diseases. Preliminary studies have demonstrated that NF-κB is activated early in acute inflammation and sepsis and may serve as an indicator of clinical severity. The present study was designed to evaluate the degree of activation of NF-κB in patients with acute appendicitis and correlate activation with clinical extent of disease. Ten patients with acute appendicitis and five control patients (elective inguinal hernia repair) were evaluated by assaying NF-κB activity preoperatively and 12 to 18 hours postoperatively. Assaying of NF-κB was determined by binding activity for consensus probes in nuclear extracts from peripheral mixed white blood cells obtained by venous puncture. The bands of NF-κB activity from gel electrophoresis were quantified with a phosphor imager and reported as units of integrated intensity. The preoperative NF-κB activity was increased in all patients with appendicitis versus the controls [mean 151 (range 97-189) vs mean 50.3 (range 13.7-77); P < 0.0001]. The increased NF-κB activity also correlated with length of time of symptoms before operation. The patients who were symptomatic for less than 24 hours had an average NF-κB value of 103 (range 97-105) versus 171.4 (range 152-189) (P < 0.0001) in those who were symptomatic 24 or more hours. The NF-κB activity did not correlate with the white blood cell count. Postoperative NF-κB binding activity in the appendicitis patients dropped to minimal levels (mean 50.3), even lower than the control patients' baseline values (mean 55.6). Control patients demonstrated low baseline values preoperatively and a slight rise postoperatively [mean 50.3 (range 13.7-77) vs mean 100 (range 45-186)]. We conclude the following: (1) NF-κB binding activity is elevated in patients with acute appendicitis and correlates with symptoms longer than 24 hours. (2) This increased activity returns to baseline values within 18 hours after appendectomy. (3) Molecular indicators of inflammation may have a role in both staging surgical inflammatory conditions and predicting ultimate outcome.

The role of Group IVA cytosolic phospholipase A2 (cPLA2α) activation in regulating macrophage transcriptional responses to Candida albicans infection was investigated. cPLA2α releases arachidonic acid for the production of eicosanoids. In mouse resident peritoneal macrophages, prostacyclin, prostaglandin E2 and leukotriene C4 were produced within minutes of C. albicans addition before cyclooxygenase 2 expression. The production of TNFα was lower in C. albicans-stimulated cPLA2α+/+ than cPLA2α-/- macrophages due to an autocrine effect of prostaglandins that increased cAMP to a greater extent in cPLA2α+/+ than cPLA2α-/- macrophages. For global insight, differential gene expression in C. albicans-stimulated cPLA2α+/+ and cPLA2α-/- macrophages (3 h) was compared by microarray. cPLA2α+/+ macrophages expressed 86 genes at lower levels and 181 genes at higher levels than cPLA2α-/- macrophages (≥2-fold, p<0.05). Several pro-inflammatory genes were expressed at lower levels (Tnfα, Cx3cl1, Cd40, Ccl5, Csf1, Edn1, CxCr7, Irf1, Irf4, Akna, Ifnγ, several IFNγ-inducible GTPases). Genes that dampen inflammation (Socs3, Il10, Crem, Stat3, Thbd, Thbs1, Abca1) and genes involved in host defense (Gja1, Csf3, Trem1, Hdc) were expressed at higher levels in cPLA2α+/+ macrophages. Representative genes expressed lower in cPLA2α+/+ macrophages (Tnfα, Csf1) were increased by treatment with a prostacyclin receptor antagonist and protein kinase A inhibitor, whereas genes expressed at higher levels (Crem, Nr4a2, Il10, Csf3) were suppressed. The results suggest that C. albicans stimulates an autocrine loop in macrophages involving cPLA2α, cyclooxygenase 1-derived prostaglandins and increased cAMP that globally effects expression of genes involved in host defense and inflammation.

The immune system is essential to maintain homeostasis with resident microbial populations, ensuring that the symbiotic host-microbial relationship is maintained. In parallel, commensal microbes significantly shape mammalian immunity at the host mucosal surface, as well as systemically. Candida albicans is an opportunistic pathogen that lives as a commensal on skin and mucosa of healthy individuals. Little is known about its capacity to modulate responses toward other microorganisms, such as colonizing bacteria (e.g., intestinal microorganisms). The aim of this study was to assess the cytokine production of PBMCs induced by commensal bacteria when these cells were primed by C. albicans. We show that C. albicans and β-1,3-glucan induce priming of human primary mononuclear cells and this leads to enhanced cytokine production upon in vitro stimulation with TLR ligands and bacterial commensals. This priming requires the β-1,3-glucan receptor dectin-1 and the noncanonical Raf-1 pathway. In addition, although purified mannans cannot solely mediate the priming, the presence of mannosyl residues in the cell wall of C. albicans is nevertheless required. In conclusion, C. albicans is able to modify cytokine responses to TLR ligands and colonizing bacteria, which is likely to impact the inflammatory reaction during mucosal diseases.

Engagement of the innate immune system and activation of inflammatory responses have been demonstrated to play an important role in myocardial ischemia/reperfusion (I/R) injury (Barry 1994; Bryant et al. 1998; Frangogiannis 2006; Kubota et al. 1997) and congestive heart failure (CHF) (Torre-Amione et al. 1996). Experimental studies and clinical investigations have shown that I/R significantly increases myocardial inflammatory cytokine expression including TNF-α, IL-1β, IL-6, IL-8, interferon-γ (IFN-γ), and intercellular adhesion molecule-1 (I-CAM-1) (Barry 1994; Bryant et al. 1998; Frangogiannis 2006; Kubota et al. 1997; Kukielka et al. 1995). These proinflammatory cytokines are directly involved in the progression of myocardial I/R injury, myocardial dysfunction, vascular wall remodeling, and heart failure (Kelly and Smith 1997; Ono et al. 1998). However, we still do not fully understand the mechanisms by which the innate immune and inflammatory responses are involved in ischemic heart diseases.