TrkC-mediated inhibition of DJ-1 degradation is essential for direct regulation of pathogenesis of hepatocellular carcinoma.

None of the previous studies has systematically explored how upregulation of TrkC plays a central role in the pathogenesis of hepatocellular carcinoma (HCC) by regulating the underlying mechanisms that promote invasion and metastasis. In this report, we demonstrated the possible association between upregulation of TrkC and acquisition of cancer stem cells traits or chemoresistance in HCC. We show that upregulation of TrkC is closely associated with the survival and progression of HCC in vivo and in vitro. Most strikingly, activation of STAT3 by TrkC-mediated inhibition of DJ-1 degradation significantly enhances the efficacy of invasion and metastasis during the progression of HCC cells. Acquiring the traits of cancer stem cells (CSCs) by TrkC/DJ-1/STAT3 signaling pathway leads to the induction of chemoresistance via upregulation of ABC transporters and anti-apoptotic genes. Also, activating the epithelial-mesenchymal transition (EMT) program by inducing EMT-transcription factor (TF)s by TrkC/DJ-1/STAT3 signaling pathway is the direct cause of multiple tumor malignancies of HCC. Thus, understanding the mechanisms by which acquisition of anticancer drug resistance by TrkC-mediated inhibition of DJ-1 degradation can help enhance the efficacy of anticancer therapies.

Mycobiota and the Contribution of Yeasts in Floor Dust of 50 Elementary Schools Characterized with Sequencing Internal Transcribed Spacer Region of Ribosomal DNA.

The assemblage of fungi including unicellular yeasts in schools is understudied. We conducted an environmental study to characterize fungal communities in classroom floor dust. We collected 500 samples from 50 elementary schools in Philadelphia, PA, and evaluated room dampness/mold conditions. Genomic DNA from dust was extracted for internal transcribed spacer 1 Illumina MiSeq sequencing to identify operational taxonomic units (OTUs) organized from DNA sequences. Differential abundance analyses were performed to examine significant differences in abundance among groups. We identified 724 genera from 1490 OTUs. The genus Epicoccum was not diverse but the most abundant (relative abundance = 18.9%). Fungi were less diverse but most dissimilar in composition in the most water-damaged classrooms compared to the least water-damaged, indicating differential effects of individual classroom water-damage on fungal compositions. We identified 62 yeast genera, representing 19.6% of DNA sequences. Cyberlindnera was the most abundant (6.1%), followed by Cryptococcus, Aureobasidium, Rhodotorula, and Candida. The average relative abundance of yeasts tended to increase with increasing dampness and mold score and was significantly (p-value = 0.048) higher in the most water-damaged classrooms (22.4%) than the least water-damaged classrooms (18.2%). Our study suggests the need for further research on the potential health effects associated with exposures to yeasts in schools.

Microbial rRNA sequencing analysis of evaporative cooler indoor environments located in the Great Basin Desert region of the United States.

Recent studies conducted in the Great Basin Desert region of the United States have shown that skin test reactivity to fungal and dust mite allergens are increased in children with asthma or allergy living in homes with evaporative coolers (EC). The objective of this study was to determine if the increased humidity previously reported in EC homes leads to varying microbial populations compared to homes with air conditioners (AC). Children with physician-diagnosed allergic rhinitis living in EC or AC environments were recruited into the study. Air samples were collected from the child's bedroom for genomic DNA extraction and metagenomic analysis of bacteria and fungi using the Illumina MiSeq sequencing platform. The analysis of bacterial populations revealed no major differences between EC and AC sampling environments. The fungal populations observed in EC homes differed from AC homes. The most prevalent species discovered in AC environments belonged to the genera Cryptococcus (20%) and Aspergillus (20%). In contrast, the most common fungi identified in EC homes belonged to the order Pleosporales and included Alternaria alternata (32%) and Phoma spp. (22%). The variations in fungal populations provide preliminary evidence of the microbial burden children may be exposed to within EC environments in this region.

Assessment of fungal diversity in a water-damaged office building.

Recent studies have described fungal communities in indoor environments using gene sequencing-based approaches. In this study, dust-borne fungal communities were elucidated from a water-damaged office building located in the northeastern region of the United States using internal transcribed spacer (ITS) rRNA gene sequencing. Genomic DNA was extracted from 5 mg of floor dust derived from 22 samples collected from either the lower floors (n = 8) or a top floor (n = 14) of the office building. ITS gene sequencing resolved a total of 933 ITS sequences and was clustered into 216 fungal operational taxonomic units (OTUs). Analysis of fungal OTUs at the 97% similarity threshold showed a difference between the lower and top floors that was marginally significant (p = 0.049). Species richness and diversity indices were reduced in the lower floor samples compared to the top floor samples and there was a high degree of compositional dissimilarity within and between the two different areas within the building. Fungal OTUs were placed in the phyla Ascomycota (55%), Basidiomycota (41%), Zygomycota (3%), Glomeromycota (0.4%), Chytridiomycota (0.3%), and unassigned fungi (0.5%). The Ascomycota classes with the highest relative abundances included the Dothideomycetes (30%) and Eurotiomycetes (16%). The Basidiomycota consisted of the classes Ustilaginomycetes (14%), Tremellomycetes (11%), and Agaricomycetes (8%). Sequence reads derived from the plant pathogen Ustilago syntherismae were the most abundant in the analysis as were obligate Basidiomycota yeast species that accounted for 12% and 11% of fungal ITS sequences, respectively. ITS gene sequencing provides additional insight into the diversity of fungal OTUs. These data further highlight the contribution of fungi placed in the phylum Basidiomycota, obligate yeasts, as well as xerophilic species that are typically not resolved using traditional culture methods.

Measurement of macrocyclic trichothecene in floor dust of water-damaged buildings using gas chromatography/tandem mass spectrometry-dust matrix effects.

Gas chromatography-tandem mass spectrometry (GC-MS/MS) was used to detect fungal secondary metabolites. Detection of verrucarol, the hydrolysis product of Stachybotrys chartarum macrocyclic trichothecene (MCT), was confounded by matrix effects associated with heterogeneous indoor environmental samples. In this study, we examined the role of dust matrix effects associated with GC-MS/MS to better quantify verrucarol in dust as a measure of total MCT. The efficiency of the internal standard (ISTD, 1,12-dodecanediol), and application of a matrix-matched standard correction method in measuring MCT in floor dust of water-damaged buildings was additionally examined. Compared to verrucarol, ISTD had substantially higher matrix effects in the dust extracts. The results of the ISTD evaluation showed that without ISTD adjustment, there was a 280% ion enhancement in the dust extracts compared to neat solvent. The recovery of verrucarol was 94% when the matrix-matched standard curve without the ISTD was used. Using traditional calibration curves with ISTD adjustment, none of the 21 dust samples collected from water damaged buildings were detectable. In contrast, when the matrix-matched calibration curves without ISTD adjustment were used, 38% of samples were detectable. The study results suggest that floor dust of water-damaged buildings may contain MCT. However, the measured levels of MCT in dust using the GC-MS/MS method could be significantly under- or overestimated, depending on the matrix effects, the inappropriate ISTD, or combination of the two. Our study further shows that the routine application of matrix-matched calibration may prove useful in obtaining accurate measurements of MCT in dust derived from damp indoor environments, while no isotopically labeled verrucarol is available.