RNA viruses in the house dust mite Dermatophagoides pteronyssinus, detection in environmental samples and in commercial allergen extracts used for in vivo diagnosis.

BACKGROUND: Allergy to house dust mites (HDM), the most important source of indoor allergens worldwide, is diagnosed and treated using natural extracts from cultures that can contain immunoactive components from the HDM microbiome, including mite-infecting viruses. This study aimed to contribute to the discovery and characterization of RNA viruses from Dermatophagoides pteronyssinus, followed by their detection in different mite-derived sources. METHODS: Viruses were assembled after in silico metatranscriptomic analysis of D. pteronyssinus RNA samples, visualized by electron microscopy, and RNA detected by direct RT-PCR or data mining. Mite culture performance was evaluated in vivo. RESULTS: Seven RNA viruses were identified in our laboratory stock colony. Picornavirus-like viral particles were detected in epithelial cells of the digestive system and in fecal pellets. Most of these viruses could be persistently transmitted to an inbred virus-free colony by inoculating fecal material from the stock colony. Upon viral infection, no significant effect could be seen on mite population growth. Transcriptomic screening confirmed the presence of homolog sequences to these viruses in independent laboratory stocks of D. pteronyssinus and in other Astigmata mites. Noteworthy, RNA from most of the viruses could be detected by RT-PCR on house dust samples, reference standards, and/or commercial diagnostic D. pteronyssinus extracts. CONCLUSIONS: Our results show that viral infections are common and widespread in D. pteronyssinus, both in natural and culture-based growth conditions. Potential effects on the mites themselves and consequences toward allergenicity in humans whether exposed naturally or after immunotherapy are discussed.

Differential toxicity biomarkers for irinotecan- and oxaliplatin-containing chemotherapy in colorectal cancer.

PURPOSE: Oxaliplatin or irinotecan is usually administered jointly with fluoropyrimidines in colorectal cancer patients treated with chemotherapy. Both drugs have different toxicity patterns. Biomarkers for predicting high-risk severe adverse reactions can help select the best treatment. METHODS: A retrospective analysis of 106 colorectal cancer patients receiving an oxaliplatin-based treatment and 56 receiving an irinotecan-based treatment was performed. One copy number variant (GSTT1) and nine polymorphisms in irinotecan and oxaliplatin metabolism, transport or DNA repair genes (ABCB1, UGT1A1, XRCC1, ERCC1, ERCC2, GSTP1) were genotyped by SNaPshot, polymerase chain reactions' length fragments, or copy number assays. RESULTS: In irinotecan-treated patients, T allele of ABCB1C1236T SNP was associated with a lower risk of asthenia(OR = 0.047; 95 % CI = 0.004­0.493; P = 0.011) and Tallele of ABCB1 C3435T SNP was associated with a lower risk of diarrhea (OR = 0.177; 95 % CI = 0.034­0.919;P = 0.039), and individuals with two copies of GSTT1 gene had a lower risk for asthenia (OR = 0.093; 95 %CI = 0.011­0.794; P = 0.030). In oxaliplatin-treated patients, carriers of one or two T variants of Asn118Asn ERCC1 SNP had a lower risk for neutropenia(OR = 0.205; 95 % CI = 0.061­0.690; P = 0.01) [corrected]. CONCLUSIONS: These biomarkers could help oncologists select the best treatment by reducing toxicity associated with irinotecan or oxaliplatin in colorectal cancer patients, thus increasing their quality of life.

Caveolar domain organization and trafficking is regulated by Abl kinases and mDia1.

The biology of caveolin-1 (Cav1)/caveolae is intimately linked to actin dynamics and adhesion receptors. Caveolar domains are organized in hierarchical levels of complexity from curved or flattened caveolae to large, higher-order caveolar rosettes. We report that stress fibers controlled by Abl kinases and mDia1 determine the level of caveolar domain organization, which conditions the subsequent inward trafficking of caveolar domains induced upon loss of cell adhesion from the extracellular matrix. Abl-deficient cells have fewer stress fibers, a smaller pool of stress-fiber co-aligned Cav1 and increased clustering of Cav1/caveolae at the cell surface. Defective caveolar linkage to stress fibers prevents the formation of big caveolar rosettes upon loss of cell adhesion, correlating with a lack of inward trafficking. Live imaging of stress fibers and Cav1 showed that the actin-linked Cav1 pool loses its spatial organization in the absence of actin polymerization and is dragged and clustered by depolymerizing filaments. We identified mDia1 as the actin polymerization regulator downstream of Abl kinases that controls the stress-fiber-linked Cav1 pool. mDia1 knockdown results in Cav1/caveolae clustering and defective inward trafficking upon loss of cell adhesion. By contrast, cell elongation imposed by the excess of stress fibers induced by active mDia1 flattens caveolae. Furthermore, active mDia1 rescues the actin co-aligned Cav1 pool and Cav1 inward trafficking upon loss of adhesion in Abl-deficient cells. Thus, caveolar domain organization and trafficking are tightly coupled to adhesive and stress fiber regulatory pathways.