Biology subjects

Hold, L. A.

Publications and source records attributed to Hold, L. A..

3 recordsLinked to original sources

bioRxiv2025

Candida auris skin colonization is mediated by Als4112 and interactions with host extracellular matrix proteins

Candida auris is an often multidrug-resistant fungal pathogen notorious for persistent skin colonization and transmission in healthcare settings. However, the mechanisms driving its adherence to skin remain poorly understood. Here, we developed in vitro systems to allow for detailed analysis of early skin colonization events and identified critical host and pathogen mediators of attachment. Across multiple strains and clades of C. auris, we identified that Als4112, a conserved adhesin, is required for skin colonization via keratinocyte attachment and direct interactions with host extracellular matrix (ECM) proteins, especially basement membrane proteins such as laminin. In a murine epicutaneous infection and human skin explants, deletion of ALS4112 significantly reduced skin colonization, underscoring its essential role in establishing cutaneous persistence. Als4112 also contributes to systemic infection, highlighting the connection between adherence and pathogenicity in this organism. Finally, coating plastic and catheter surfaces with collagen I or III markedly inhibited C. auris attachment and biofilm formation, offering an approach to curb nosocomial transmission. Our study highlights the critical role of Als4112 in C. auris colonization and virulence in vivo, making it an attractive target for future vaccine development. This study also explores the potential of specific collagen coatings as a novel strategy to prevent C. auris adherence to abiotic surfaces, offering new therapeutic avenues to control the spread of C. auris in healthcare settings.

microbiology↗

bioRxiv2025

AMPK signaling is dysregulated in human tendinopathy and loss of AMPKα1 leads to cell, matrix and mechanical dysfunction in mouse Achilles tendon

Tendinopathy is a debilitating tendon disorder affecting millions of people, characterized by pain, swelling, and diminished biomechanical properties. While the precise mechanisms underlying tendon homeostasis remain unclear, metabolic regulation plays a critical role. In this study, we combine transcriptomic analysis of human tendinopathic samples with a conditional mouse model in which Prkaa1 (encoding AMPK1) is selectively deleted in tendon progenitors to elucidate the role of AMPK signaling in tendon homeostasis. RNA sequencing of diseased human tendons revealed downregulation of key metabolic genes, including several involved in the mitochondrial electron transport chain and AMPK signaling pathways, alongside an increase in markers associated with senescence and a secretory inflammatory profile. In parallel, mice with loss of Prkaa1 function exhibited normal postnatal development; however, by one month of age, tendons demonstrated widespread transcriptional alterations related to cell cycle regulation and ECM organization. By three months, AMPK1-deficient tendons showed significant reductions in mechanical strength and increased expression of senescence markers p21 and p16, progressing to prominent ectopic calcification with age. In vitro studies further confirmed that tendon fibroblasts lacking AMPK1 have altered ECM substrate adhesion profiles. Importantly, voluntary exercise partially rescued these deficits by enhancing ECM organization and reducing senescence marker expression. Collectively, our findings demonstrate that AMPK1 is critical for maintaining energy balance, regulating ECM remodeling, and preventing premature cellular senescence in tendon. These insights highlight AMPK signaling as a promising therapeutic target and underscore the beneficial role of exercise in mitigating tendinopathic changes.

pathology↗

bioRxiv2024

Functional Changes to Achilles Tendon and Enthesis in a Mouse Model of an Adolescent Masculine Gender-Affirming Hormone Treatment

Many transgender youth seek gender affirming care, such as puberty suppression, to prolong decision-making and to align their physical sex characteristics with their gender identity. During peripubertal growth, connective tissues such as tendon rapidly adapt to applied mechanical loads (e.g., exercise) yet if and how tendon adaptation is influenced by sex and gender affirming hormone therapy during growth remains unknown. The goal of this study was to understand the how pubertal suppression influences the structural and functional properties of the Achilles tendon using an established mouse model of transmasculine gender affirming hormone therapy. C57BL/6N female-born mice were assigned to experimental groups to mimic gender-affirming hormone therapy in human adolescents, and treatment was initiated prior to the onset of puberty (at postnatal day 26, P26). Experimental groups included controls and mice serially treated with gonadotropin release hormone analogue (GnRHa), delayed Testosterone (T), or GnRHa followed by T. We found that puberty suppression using GnRHa, with and without T, improved the overall tendon load capacity in female-born mice. Treatment with T resulted in an increase in the maximum load that tendon can withstand before failure. Additionally, we found that GnRHa, but not T, treatment resulted in a significant increase in cell density at the Achilles enthesis. NEW & NOTEWORTHYThese findings demonstrate that puberty suppression or testosterone does not negatively influence tendon structural or functional properties in a mouse model of transmasculine gender affirming care. In all treatment groups, the ability of the tendon to withstand load was significantly increased. Puberty suppression with GnRHa significantly increased enthesis cell density, suggesting an extended growth phase. These findings elucidate the effects of gender affirming care on the structural and functional properties of the tendon and enthesis.

physiology↗