Flores, A. E. | bioRxiv Science

bioRxiv2021

Dynamic structural cell responses in the thymus to acute injury, regeneration, and age

The thymus is essential for establishing adaptive immunity yet undergoes age-related atrophy leading to compromised immune responsiveness. The thymus is also extremely sensitive to acute insult and although capable of regeneration, this capacity declines with age. Focusing on non-hematopoietic stromal cells, and using single-cell and spatial transcriptomics, lineage-tracing, and advanced imaging, we discovered two atypical thymic epithelial cell (TEC) states that emerged with age. Age-associated (aa)TECs formed atypical high-density epithelial clusters that were devoid of thymocytes, an accretion of non-functional thymic tissue that worsened with age and exhibited features of partial epithelial-to-mesenchymal transition (EMT). In silico interaction analysis revealed that aaTEC emergence drew tonic signals from other TEC populations at baseline, acting as a sink for TEC growth factors. Following damage, aaTEC expanded substantially, further perturbing trophic pathways, and correlating with defective regeneration of the involuted thymus. These findings define a unique feature of thymic involution linked to immune aging.

immunology↗

bioRxiv2019

Multiplex PCR for simultaneous genotyping of kdr mutations V410L, V1,016I and F1,534C in Aedes aegypti (L.).

BackgroundKnock down resistance (kdr) is the main mechanism that confers resistance to pyrethroids and DDT. This is a product of nonsynonymous mutations in the he voltage-gated sodium channel (VGSC) gene, these mutations produce a change of a single amino acid which reduces the affinity of the target site for the insecticide molecule. In Mexico, V410L, V1,016I and F1,534C mutations are common in pyrethroid-resistant Aedes aegypti (L.) populations. MethodsA multiplex PCR was developed to detect the V410L, V1,016I and F1,534C mutations in Ae. aegypti. The validation of the technique was carried out using wild populations previously characterized for the three mutations through allele-specific PCR (AS-PCR) and with different levels of genotypic frequencies. ResultsThe standardized protocol for multiplex endpoint PCR was highly effective in detecting 12 genotypes in five wild Ae. aegypti populations from Mexico. A complete concordance with AS-PCR was found for the simultaneous detection of the three kdr mutations. ConclusionsOur diagnostic method is highly effective for the simultaneous detection of V410L, V1,016I and F1,534C, when they co-occur. This technique represents a viable alternative to complement and strengthen current monitoring and resistance management strategies against Ae. aegypti.

molecular biology↗