Biology subjects

King, R. E.

Publications and source records attributed to King, R. E..

5 recordsLinked to original sources

bioRxiv2025

Allelic Variation in CYP3A4 and PLB1 Drives Feed Efficiency and Immunometabolic Resilience in Beef Cattle

We evaluated genetic markers for feed efficiency and immunocompetence in 108 crossbred steers (217 {+/-} 8.2 kg) fed a high-forage total mixed ration for 35 days, using GrowSafe8000 intake nodes to calculate residual feed intake (RFI). From the 20 most efficient (low-RFI) and 20 least efficient (high-RFI) animals, we genotyped three metabolic loci (CYP3A4 rs438103222, PLB1 rs456635825, CRAT rs876019788) and profiled blood mRNA levels of these plus eight innate/adaptive immune genes. Logistic regression revealed that CYP3A4 and PLB1 polymorphisms--but not CRAT--were strongly associated with initial and final body weight, average daily gain, and feed intake: CYP3A4 A/A and PLB1 A-allele carriers achieved superior growth on reduced feed. Haplotype reconstruction across the three loci defined eight multi-SNP combinations, with the C-A-A haplotype enriched in low-RFI steers and combinations harboring CYP3A4 A and PLB1 A alleles linked to low RFI. Intriguingly, these favorable genotypes also overlapped with up-regulation of immune sensors and effectors (e.g., CD14, TLR4, TNF-), indicating a coordinated metabolic-immune adaptation in efficient cattle. Collectively, our results validate CYP3A4 and PLB1 as high-impact quantitative trait nucleotides for marker-assisted selection aimed at simultaneously improving feed efficiency and immune resilience in beef production.

genetics↗

bioRxiv2025

The Effects of Hypothermic Storage on Passaged Chondrocyte Viability and Redifferentiation Potential

Cell-based transplantation therapies, such as autologous chondrocyte implantation (ACI), are used to treat focal cartilage defects caused by trauma or degeneration. In ACI, chondrocytes are isolated from non-load-bearing regions of healthy cartilage regions and then sent to a cell manufacturing laboratory, where they are expanded for cell number in monolayer culture. Once a large number of cells are obtained, they are transported to the clinic for reimplantation into the defect site. The storage and transport conditions from cell manufacturing to implantation may be a critical time that could influence cell viability and redifferentiation potential. Although hypothermic storage at sub-physiological temperatures is commonly used to preserve cell viability, long-term storage of cartilage under hypothermic conditions can impair chondrocyte viability and function. However, the impact of short-term, acute hypothermic storage on passaged chondrocytes remains largely unknown. We tested the hypothesis that acute hypothermic storage negatively impacts passaged chondrocyte viability and reduces the capacity for redifferentiation. Passaged chondrocytes were stored either in monolayer culture or in suspension at 36, 19 or 8{degrees}C. In monolayer culture, hypothermic temperatures preserved cell viability with no difference compared to storage at 36{degrees}C for up to three days. Additionally, hypothermic temperatures promoted cell rounding, reduced proliferative capacity, depolymerized filamentous actin, and led to a slight reduction in the mRNA levels of specific matrix molecules compared to 36{degrees}C. Intriguingly, the effects of hypothermia were context-dependent. Exposure of passaged cells in suspension to hypothermia promoted the maintenance of cell viability and reduced aggregation compared to 36{degrees}C. When stored at 8{degrees}C in suspension, passaged cells exhibited enhanced expression of specific matrix molecule mRNA levels compared to cells at 36{degrees}C in suspension. Subsequently, when passaged cells in suspension at 8{degrees}C were seeded in 3D within adherent agarose molds, there was an increase in aggrecan expression 10 days after seeding. The tissues formed by cells stored in suspension at 9{degrees}C were thicker and stained more intensely for aggrecan. Therefore, in contrast to our hypothesis, we found that hypothermic storage did not have a negative impact; when stored for 1 day in suspension, it had lasting effects on matrix deposition. The storage of passaged chondrocytes under hypothermic conditions may be beneficial for ACI, warranting further investigations of cell hypothermic storage for in vivo repair.

bioengineering↗

bioRxiv2024

Invasive cancer and spontaneous regression two weeks after papillomavirus infection

Development of invasive cancer in mammals is thought to require months or years after initial events such as mutation or viral infection. Rarely, invasive cancers regress spontaneously. We show that cancers can develop and regress on a timescale of weeks, not months or years. Invasive squamous cell carcinomas developed in normal adult, immune-competent mice as soon as 2 weeks after infection with mouse papillomavirus MmuPV1. Tumor development, regression or persistence was tissue- and strain-dependent. Cancers in infected mice developed rapidly at sites also prone to papillomavirus-induced tumors and cancers in humans - the throat, anus, and skin - and their frequency was increased in mice constitutively expressing the papillomavirus E5 oncogene, which MmuPV1 lacks. Cancers and dysplasia in the throat and anus regressed completely within 4-8 weeks of infection; however, skin lesions in the ear persisted. T-cell depletion in the mouse showed that regression of throat and anal tumors requires T cells. We conclude that papillomavirus infection suffices for rapid onset of invasive cancer, and persistence of lesions depends on factors including tissue type and host immunity. The speed of these events should promote rapid progress in the study of viral cancer development, persistence, and regression. Summary Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=112 SRC="FIGDIR/small/611275v1_ufig1.gif" ALT="Figure 1"> View larger version (33K): org.highwire.dtl.DTLVardef@1da9642org.highwire.dtl.DTLVardef@1bef109org.highwire.dtl.DTLVardef@c2ba0eorg.highwire.dtl.DTLVardef@451baf_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2021

The production of 4,182 mouse lines identifies experimental and biological variables impacting Cas9-mediated mutant mouse line production

The International Mouse Phenotyping Consortium (IMPC) systematically produces and phenotypes mouse lines with presumptive null mutations to provide insight into gene function. The IMPC now uses the programmable RNA-guided nuclease Cas9 for its increased capacity and flexibility to efficiently generate null alleles in the C57BL/6N strain. In addition to being a valuable novel and accessible research resource, the production of 3,313 knockout mouse lines using comparable protocols provides a rich dataset to analyze experimental and biological variables affecting in vivo gene engineering with Cas9. Mouse line production has two critical steps - generation of founders with the desired allele and germline transmission (GLT) of that allele from founders to offspring. A systematic evaluation of the variables impacting success rates identified gene essentiality as the primary factor influencing successful production of null alleles. Collectively, our findings provide best practice recommendations for using Cas9 to generate alleles in mouse essential genes, many of which are orthologs of genes linked to human disease.

genetics↗

bioRxiv2019

A resource of targeted mutant mouse lines for 5,061 genes

The International Mouse Phenotyping Consortium reports the generation of new mouse mutant strains for over 5,000 genes from targeted embryonic stem cells on the C57BL/6N genetic background. This includes 2,850 null alleles for which no equivalent mutant mouse line exists, 2,987 novel conditional-ready alleles, and 4,433 novel reporter alleles. This nearly triples the number of genes with reporter alleles and almost doubles the number of conditional alleles available to the scientific community. When combined with more than 30 years of community effort, the total mutant allele mouse resource covers more than half of the genome. The extensively validated collection is archived and distributed through public repositories, facilitating availability to the worldwide biomedical research community, and expanding our understanding of gene function and human disease.

genetics↗