Candida auris undergoes adhesin-dependent and -independent cellular aggregation.

Candida auris is a fungal pathogen of humans responsible for nosocomial infections with high mortality rates. High levels of resistance to antifungal drugs and environmental persistence mean these infections are difficult to treat and eradicate from a healthcare setting. Understanding the life cycle and the genetics of this fungus underpinning clinically relevant traits, such as antifungal resistance and virulence, is of the utmost importance to develop novel treatments and therapies. Epidemiological and genomic studies have identified five geographical clades (I-V), which display phenotypic and genomic differences. Aggregation of cells, a phenotype primarily of clade III strains, has been linked to reduced virulence in some infection models. The aggregation phenotype has thus been associated with conferring an advantage for (skin) colonisation rather than for systemic infection. However, strains with different clade affiliations were compared to infer the effects of different morphologies on virulence. This makes it difficult to distinguish morphology-dependent causes from clade-specific or even strain-specific genetic factors. Here, we identify two different types of aggregation: one induced by antifungal treatment which is a result of a cell separation defect; and a second which is controlled by growth conditions and only occurs in strains with the ability to aggregate. The latter aggregation type depends on an ALS-family adhesin which is differentially expressed during aggregation in an aggregative C. auris strain. Finally, we demonstrate that macrophages cannot clear aggregates, suggesting that aggregation might after all provide a benefit during systemic infection and could facilitate long-term persistence in the host.

Labelling of Candida auris Cell Walls to Examine Levels of PAMP Exposure by Flow Cytometry and Fluorescence Microscopy.

Pathogen-associated molecular patterns (PAMPs) of the fungal cell wall are primary targets for the innate immune system of animals. Therefore, characterizing PAMP exposure of fungal pathogens helps to elucidate how they interact with their hosts at a molecular level. Fluorescent labelling can be used to monitor exposure of multiple fungal cell wall PAMPs in a single experiment. Here, we describe a protocol to simultaneously label chitin, mannan, and ß-1,3-glucan in Candida auris to study these PAMPs by fluorescence microscopy and allow high-throughput examination of their exposure by flow cytometry.

Non-canonical signalling mediates changes in fungal cell wall PAMPs that drive immune evasion.

To colonise their host, pathogens must counter local environmental and immunological challenges. Here, we reveal that the fungal pathogen Candida albicans exploits diverse host-associated signals to promote immune evasion by masking of a major pathogen-associated molecular pattern (PAMP), ß-glucan. Certain nutrients, stresses and antifungal drugs trigger ß-glucan masking, whereas other inputs, such as nitrogen sources and quorum sensing molecules, exert limited effects on this PAMP. In particular, iron limitation triggers substantial changes in the cell wall that reduce ß-glucan exposure. This correlates with reduced phagocytosis by macrophages and attenuated cytokine responses by peripheral blood mononuclear cells. Iron limitation-induced ß-glucan masking depends on parallel signalling via the iron transceptor Ftr1 and the iron-responsive transcription factor Sef1, and the protein kinase A pathway. Our data reveal that C. albicans exploits a diverse range of specific host signals to trigger protective anticipatory responses against impending phagocytic attack and promote host colonisation.

Alanine Aminotransferase Is a Marker of Lipotoxicity Consequences and Hyperandrogenemia in Women with Polycystic Ovary Syndrome.

BACKGROUND: Several studies have reported higher levels of Alanine aminotransferase (ALT) in women with polycystic ovary syndrome (PCOS) compared with control subjects. Plasma ALT levels are considered a marker of hepatic lipotoxicity because of their significant associations with different hepatic metabolic dysfunctions, such as hepatic steatosis and hepatic insulin resistance. METHODS: Retrospective chart review aiming to assess, in PCOS women, the relationship between ALT levels and measures of lipotoxicity consequences that are available clinically, both during fasting and using the oral glucose tolerance test. RESULTS: Women (n = 132) with PCOS, were in average 27.9 years of age, with a mean body mass index of 34.1 kg/m2 and 49% had a metabolic syndrome (MetS). ALT levels were significantly correlated with homeostatic model assessment for insulin resistance (r = 0.42, P < 0.001), HDL-C (r = -0.31, P < 0.001), Matsuda index (-0.45, P < 0.001), insulin secretion-sensitivity index-2 (-0.26, P = 0.043), and free testosterone (0.38, P < 0.001), but not with fasting glucose and triglyceride levels. ALT cutoff ≥24 IU/L was associated with all these parameters, including fasting glucose (P = 0.021) and triglyceride levels (P = 0.041), and detected more women with the MetS (59.2% vs. 36.1%, P = 0.008) and whole-body insulin resistance (Matsuda index <12.3 L2·10/mmol2, 85.3% vs. 51.9%, P = 0.004). CONCLUSIONS: Plasma ALT levels seem to be a strong predictor not only of liver lipotoxicity but also of systemic lipotoxic consequences and hyperandrogenemia in women with PCOS. Although it requires validation in another study, an ALT cutoff of ≥24 IU/L may help clinicians identify women with increased metabolic risks.

Polymorphisms of the vincristine pathway and response to treatment in children with childhood acute lymphoblastic leukemia.

BACKGROUND: Vincristine (VCR) is a standard component in the treatment of childhood acute lymphoblastic leukemia (ALL). VCR cytotoxicity is primarily due to its ability to disrupt the formation of microtubules of the mitotic spindle. PATIENTS & METHODS: Seventeen polymorphisms in regulatory and coding regions of genes controlling VCR targets (TUBB1, MAP4, ACTG1 and CAPG) or potentially influencing VCR levels (ABCB1 and CYP3A5) were investigated for an association with peripheral neuropathy and outcome in childhood ALL patients. RESULTS: High-grade neurotoxicity was more frequent in carriers of the A allele of synonymous (Ala310) G to A (rs1135989) variation in the ACTG1 gene. Substitution (rs4728709) in the promoter of the ABCB1 gene had a protective effect against lower grade neurotoxicity and C to A variation (rs3770102) located 17 nucleotides upstream from the transcription start site had a protective effect against high-grade neurotoxicity. Patients with the ABCB1 3435TT genotype had lower event-free survival; the association with event-free survival was not supported by the analysis in the replication patient set. CONCLUSION: The polymorphisms in the ACTG1, CAPG and ABCB1 genes may modulate VCR-related neurotoxicity, whereas the risk of relapse seems not to be affected by the genes of the VCR pathway.

Expression of the senescence marker p16INK4a in skin biopsies of acute lymphoblastic leukemia survivors: a pilot study.

BACKGROUND: Most childhood cancer survivors will develop ionizing radiation treatment-related health conditions that, in many instances, resemble age-associated pathologies. Treatment-induced premature senescence could be an underlying mechanism. FINDINGS: Here we wanted to know whether the expression of p16INK4a, a senescence/aging biomarker, is increased in skin biopsies of acute lymphoblastic leukemia survivors (ALL), previously exposed to chemotherapy and radiation therapy. Several years post-treatments, we found p16INK4a mRNA levels are 5.8 times higher in scalp skin biopsies (targeted by cranial irradiation therapy) compared to buttocks skin biopsies (n = 10, p = 0.01). CONCLUSIONS: These results demonstrate for the first time that premature senescence is induced in pediatric cancer survivors and that p16INK4a expression could be used as a potential biomarker in this population.