Candida pathogens induce protective mitochondria-associated type I interferon signalling and a damage-driven response in vaginal epithelial cells.

Vaginal candidiasis is an extremely common disease predominantly caused by four phylogenetically diverse species: Candida albicans; Candida glabrata; Candida parapsilosis; and Candida tropicalis. Using a time course infection model of vaginal epithelial cells and dual RNA sequencing, we show that these species exhibit distinct pathogenicity patterns, which are defined by highly species-specific transcriptional profiles during infection of vaginal epithelial cells. In contrast, host cells exhibit a homogeneous response to all species at the early stages of infection, which is characterized by sublethal mitochondrial signalling inducing a protective type I interferon response. At the later stages, the transcriptional response of the host diverges in a species-dependent manner. This divergence is primarily driven by the extent of epithelial damage elicited by species-specific mechanisms, such as secretion of the toxin candidalysin by C. albicans. Our results uncover a dynamic, biphasic response of vaginal epithelial cells to Candida species, which is characterized by protective mitochondria-associated type I interferon signalling and a species-specific damage-driven response.

Vulvovaginal candidiasis in a murine model of diabetes emphasizing the invasive ability of etiological agents.

Aim: To compare the pathogenesis of vulvovaginal candidiasis by three Candida species in diabetic mice. Materials & methods: Estrogenized and diabetic mice were challenged with C. albicans, C. tropicalis and C. glabrata. Results: Diabetic animals infected with C. albicans and C. tropicalis maintained the highest fungal burden, despite of high levels of proinflammatory cytokines (IL-6 and TNF-α), respectively. For C. glabrata, the results were similar in diabetic and nondiabetic groups. Conclusion:C. tropicalis was as invasive as C. albicans, and both were more effective than C. glabrata. This ability was attributed to filamentation, which may be stimulated by glucose levels from vaginal fluid. In addition, the high burden may be attributed to the apparent immunological inefficiency of the diabetic host.

Differential Expression of Local Immune Response Genes in the Vagina: Implication for the Diagnosis of Vaginal Infections.

Transcription profiles of genes of local immune response were determined in the vagina of women with bacterial vaginosis, aerobic vaginitis, and vulvovaginal candidosis for detection of the most specific immune markers for these vaginal infections. Laboratory diagnosis of the vaginal infections was performed microscopically; the inflammatory reaction in the vagina (leukorrhea) was defined as the presence of >10 white blood cells per field of view. Transcription profiles of IL1b, IL10, IL18, TNFα, TLR4, GATA3, and CD68 were determined using reverse-transcription quantitative real-time PCR. The strongest predictors of aerobic vaginitis were increased levels of IL1b and IL10 mRNA. Bacterial vaginosis was strongly associated with reduced levels of IL18 and GATA3 mRNA. Increased levels of IL1b and TLR4 transcripts showed significant discriminatory power for vulvovaginal candidosis and leukorrhea. The results of this study suggest differential expression of local immune response genes in the vagina of women with different vaginal infections. Detection of specific immune markers in the vagina using reverse-transcriptase PCR could supplement PCR detection of abnormal vaginal microflora for the diagnosis of vaginal infections.

The Case for an Expanded Concept of Trained Immunity.

Trained immunity was originally proposed as a program of innate immunity memory by innate immunity cells of hematopoietic origin such as the monocytes/macrophages and the NK cells. Here I discuss some old and new data justifying this program and some specific, still unanswered, questions it raises regarding the model fungus Candida albicans and the chronic, inflammatory vulvovaginal disease it causes. Building upon this well-established program, the recent reports that epithelial cells of mammals can also acquire memory from previous stimulations, and the apparent intrinsic ability of many living cells from bacteria to mammals to learn from experience, I suggest an expansion of the concept of trained immunity to include all cells of different lineages with the potential of memorizing previous microbial encounters. This expansion would better fit the complexity of innate immunity and the role it plays in infectious and inflammatory diseases.

High glucose-mediated overexpression of ICAM-1 in human vaginal epithelial cells increases adhesion of Candida albicans.

To investigate the involvement of ICAM-1 in the adhesion of Candida to the genitourinary epithelial cells in high glucose, we examined the adhesion of Candida albicans or Candida glabrata to human vaginal epithelial cells (VK2/E6E7) or human vulvovaginal epidermal cells (A431). These cells were cultured in 100, 500 or 3000 mg/dL glucose for three days and inoculated with Candida for 60 minutes. Followed by, adhering of Candida to the cells, which were counted. While the adhesion of Candida albicans to VK2/E6E7 significantly increased in the high glucose, A431 did not. We next examined the expression of ICAM-1 as a ligand on the epithelial cells. ICAM-1 expression was increased in VK2/E6E7 cultured in the high glucose; however, the expression level in A431 was not high compared with VK2/E6E7. This data suggested that ICAM-1 functions as one of ligands in the adhesion of Candida albicans to the vaginal epithelial cells in a high glucose environment. Impact statement What is already known on the subject: Candida's complement receptor is involved in the adhesion to epithelial cells. The expression of this receptor has been reported to increase as glucose concentration increases. This is considered as a contributing factor to the high risk for vulvovaginal candidiasis (VVC) in diabetes. On the host side, diabetic patients have a factor that facilitates adhesion of Candida to epithelial cells. This factor has been unknown until recently. What the results of this study add: In this study, we used a vaginal epithelial cell line and showed that the adhesion of C. albicans to cells increased at higher glucose concentrations. At the same time, ICAM-1 expression of cells also increased. Thereby, it is suggested that the expression of ICAM-1 in vaginal epithelial cells is increased by glucose such as urinary sugar in diabetic patients and is a condition for facilitating adhesion of Candida. What the implications are of these findings for clinical practice and/or further research: We expect not only host immune dysfunction but also alteration in epithelial cells will be focussed on as a cause of VVC in diabetic patients.

[Vulvovaginal candidiasis: An old disease with new challenges]. / Candidiasis vulvovaginal: una antigua enfermedad con nuevos desafíos.

Vulvovaginal candidiasis is an old disease that, even in a modern world, continues to have a high incidence. Despite the therapeutic advances, treatments are not always effective, and our understanding of the pathogenesis of this fungal infection is still incomplete. A discussion is presented in this article on the most significant developments related to the fungal virulence factors, the role of the immunological mechanisms involved in the vaginal protection, and the genetic alterations that confer susceptibility to the recurrent form of this mycosis. Current treatments, the use of new agents with antifungal activity, as well as the development of strategies, such as vaccination, are approached in the context of the complex scenario that governs the interactions between Candida and its host.

Evaluation of Micronuclei, Nuclear Anomalies and the Nuclear/Cytoplasmic Ratio of Exfoliated Cervical Epithelial Cells in Genital Candidiasis.

OBJECTIVE: Candida is the most common cause of fungal infections. The aim of this study was to fill the gaps in the current knowledge on the frequencies of micronuclei and nuclear anomalies, and the nucleus/cytoplasmic ratio in genital candidiasis. STUDY DESIGN: A total of 88 Papanicolaou- stained cervical smears, which comprised Candida spp. (n = 44) and control cases with no infectious agent (n = 44), were studied. In each smear, cells with micronuclei and nuclear anomalies were counted in 1,000 epithelial cells and also nuclear and cellular areas were evaluated using image analysis software at a magnification of ×400. RESULTS: The frequencies of micronucleated and binucleated cells and cells with perinuclear halos, and the nucleus/cytoplasmic ratio of epithelial cells were higher in the Candida-infected group compared with the control group (p < 0.05). CONCLUSIONS: Genital candidiasis is able to induce changes in the size and shape of epithelial cells. The nuclear/cytoplasmic ratio and the frequency of micronuclei may reflect the DNA damage in the cervical epithelium. Micronucleus scoring could be used to screen the genomic damage profile of epithelial cells in candidiasis.

Mouse strain-dependent differences in estrogen sensitivity during vaginal candidiasis.

The animal models available for studying the immune response to genital tract infection require induction of a pseudo estrous state, usually achieved by administration of 17-ß-estradiol. In our experimental model of vaginal candidiasis, under pseudo estrus, different strains of mice were used. We observed major differences in the clearance of Candida albicans infection among the different strains, ascribable to differing susceptibility to estradiol treatment. In the early phase of infection CD1, BALB/c, C57BL/6 albino and C57BL/6 mice were colonized to similar levels, while in the late phase of infection, BALB/c mice, which are considered genetically resistant to C. albicans infection, exhibited greater susceptibility to vaginal candidiasis than CD1 and C57BL/6 albino strains of mice. This was because estradiol induced "per se" enlarged and fluid-filled uteri, more pronounced in infected mice and consistently more evident in BALB/c and C57BL/6 mice than in CD1 mice. Unlike CD1, BALB/c and C57BL/6 mice showed a heavy fungal colonization of the uterus, even though C57BL/6 mice apparently cleared C. albicans from the vagina. The presence of C. albicans in the vagina and uterus was accompanied by a heavy bacterial load. Collectively these observations prompted us to carry out a careful analysis of estradiol effects in a mouse model of vaginal infection.

Human dectin-1 deficiency and mucocutaneous fungal infections.

Mucocutaneous fungal infections are typically found in patients who have no known immune defects. We describe a family in which four women who were affected by either recurrent vulvovaginal candidiasis or onychomycosis had the early-stop-codon mutation Tyr238X in the beta-glucan receptor dectin-1. The mutated form of dectin-1 was poorly expressed, did not mediate beta-glucan binding, and led to defective production of cytokines (interleukin-17, tumor necrosis factor, and interleukin-6) after stimulation with beta-glucan or Candida albicans. In contrast, fungal phagocytosis and fungal killing were normal in the patients, explaining why dectin-1 deficiency was not associated with invasive fungal infections and highlighting the specific role of dectin-1 in human mucosal antifungal defense.

Polymorphism in a gene coding for the inflammasome component NALP3 and recurrent vulvovaginal candidiasis in women with vulvar vestibulitis syndrome.

OBJECTIVE: Patients with vulvar vestibulitis syndrome (VVS) and control subjects were tested for a polymorphism in the gene coding for the NALP3 component of inflammasomes, cytoplasmic structures regulating interleukin (IL)-1beta production. STUDY DESIGN: DNA from 143 women with VVS and 182 control women were tested for a length polymorphism in intron 4 of the gene (CIAS1) that codes for NALP3. Vestibular tissue was examined for NALP3 expression. Whole blood cultures were tested for Candida albicans-induced IL-1beta production. RESULTS: The allele 12 frequency was higher in control subjects than in the patients with VVS (P = .02). Among patients with VVS and a self-reported history of recurrent vulvovaginal candidiasis (RVVC), the allele 7 frequency was 43.9% as compared with 30.8% in patients with no history of RVVC and 26.9% in control women (P = .035 vs other patients and .001 vs control subjects). NALP3 was identified in vestibular tissue. C albicans-induced IL-1beta production was reduced in samples from women with the 7,7 genotype (P = .030). CONCLUSION: Polymorphism in the CIAS1 gene may play a central role in the triggering of VVS in a subset of patients.

Mannose-binding lectin and vulvovaginal candidiasis.

OBJECTIVE: To investigate the effect of mannose-binding lectin (MBL) gene polymorphism on the immune system and the significance of vaginal MBL concentration in the pathogenesis of vulvovaginal candidiasis (VVC) and recurrent VVC (rVVC). PATIENTS AND METHODS: Mannose-binding lectin concentrations in CVL samples from 111 women were collected between August 2004 and November 2004, 51 with VVC, 6 with rVVC patients, and 54 healthy women. CVL MBL concentrations were determined by enzyme-linked immunosorbent assay, and MBL gene polymorphism was analyzed by polymerase chain reaction and the restriction fragment length polymorphism method. RESULTS: Cervicovaginal lavage MBL concentration (17.80 ng/mL) and gene mutation frequency (33.33%) were both significantly higher in women with VVC (P<0.01) than in controls (odds ratio [OR], 2.93; 95% confidence interval [CI], 1.14-7.57; P<0.05). On the other hand, MBL concentration was lower in women with rVVC (0.30 ng/mL) than in controls (1.28 ng/mL) (P<0.05), although MBL gene mutation frequency (83.33%) was significantly higher in women with rVVC than in controls (OR, 26.87; 95% CI, 2.76-261.65; P<0.01). CONCLUSIONS: The presence of VVC can increase vaginal MBL level, which may be an immune response against Candida albicans infection; in women with rVVC, the low level of MBL in the vagina caused by mutation in the MBL gene may play a role in the recurrence of the infection.

Genetic susceptibility of mice to Candida albicans vaginitis correlates with host estrogen sensitivity.

We compared susceptibility to Candida vaginitis in derived murine substrains differing in sensitivity to estrogen (CD-1 and CD10, resistant; CD3 and C57BL/6 responsive), and in F1 crosses. The order of decreasing resistance was CD-1 > or = CD10 > or = CD10 x CD3F1 > CD10 x B6F1 > CD3 > C57BL/6 and correlated with estrogen responsiveness in endocrine disruptor assays. Resistance to Candida vaginitis appears additive in CD10 x B6F1 animals and dominant in CD10 x CD3F1 animals.

A murine model of Candida glabrata vaginitis.

Vaginal Candida glabrata infections have increased significantly in recent years and are particularly common in women with uncontrolled diabetes mellitus. Efforts to understand the pathogenesis and treatment of this infection have been hindered by the lack of experimental animal models. Before onset of hyperglycemia, nonobese diabetic (NOD) mice inoculated intravaginally with clinical C. glabrata isolates were shown to support high vaginal titers of C. glabrata for > 14 days with evidence for superficial invasion of vaginal epithelial tissue. In contrast, congenic diabetic-resistant mice and mice susceptible to Candida albicans infections were significantly less susceptible to vaginal infection by C. glabrata, suggesting a potential link between the susceptibility of NOD mice to diabetes and their susceptibility to vaginal C. glabrata infections. This animal model of C. glabrata vaginitis provides a means to study the genetics and pathogenesis of C. glabrata infections and to evaluate the efficacy of antimycotic agents against C. glabrata.

Association of recurrent candidal vaginitis with inheritance of Lewis blood group antigens.

A subset of women with candidal vulvovaginitis have no known risk factors for recurrent episodes. Although there are reports of an association of blood group antigens with various infections, no such association has been described with candidal vulvovaginitis. The ABO, P1, and Lewis group phenotypes of 35 women with recurrent vulvovaginitis but without other chronic infections were determined. These were compared with those of a control group of 40 women without a history of candidal vulvovaginitis. The distribution of ABO blood types and P blood group phenotype did not differ from those in controls. However, vulvovaginitis patients were more likely than controls to be classified as Lea-b- (chi 2 = 6.4, 1 df, P = .011). Women without known predisposing factors may have a genetic predisposition to recurrent vulvovaginitis, as evidenced by a higher frequency of Lea-b- phenotype profiles compared with controls.