Biology subjects

Hudgins, A. D.

Publications and source records attributed to Hudgins, A. D..

3 recordsLinked to original sources

bioRxiv2024

In vitro heterochronic parabiosis identifies pigment epithelium-derived factor as a systemic mediator of rejuvenation by young blood

Several decades of heterochronic parabiosis (HCPB) studies have demonstrated the restorative impact of young blood, and deleterious influence of aged blood, on physiological function and homeostasis across tissues, although few of the factors responsible for these observations have been identified. Here we develop an in vitro HCPB system to identify these circulating factors, using replicative lifespan (RLS) of primary human fibroblasts as an endpoint of cellular health. We find that RLS is inversely correlated with serum donor age and sensitive to the presence or absence of specific serum components. Through in vitro HCPB, we identify the secreted protein pigment epithelium-derived factor (PEDF) as a circulating factor that extends RLS of primary human fibroblasts and declines with age in mammals. Systemic administration of PEDF to aged mice reverses age-related functional decline and pathology across several tissues, improving cognitive function and reducing hepatic fibrosis and renal lipid accumulation. Together, our data supports PEDF as a systemic mediator of the effect of young blood on organismal health and homeostasis and establishes our in vitro HCPB system as a valuable screening platform for the identification of candidate circulating factors involved in aging and rejuvenation.

cell biology↗

bioRxiv2023

Longevity-associated SMAD3 non-coding centenarian variant impairs a cell-type specific enhancer to reduce inflammation

Given the pro and anti-geronic roles of the TGF-{beta} superfamily in aging, we hypothesized that human longevity involves genetic variation in TGF-{beta} signaling genes. Here we utilized a candidate functional genomic approach to identify and characterize functional variants in TGF- {beta} signaling associated with human longevity. Targeted sequencing of 113 genes involved in aging- associated TGF- {beta} signaling in an Ashkenazi Jewish centenarian cohort identified genetic variants robustly associated with human longevity. In particular, a centenarian-enriched intronic variant residing in a cell-type specific enhancer in SMAD3, a critical receptor-regulated TGF- {beta} signal transducer, was identified. This non-coding SMAD3 variant (rs8040709) altered binding of ELK1, a member of the ETS family of transcription factor important for enhancer activity in certain cell types, resulting in reduced SMAD3 expression. Analysis of the variant in cell types derived from gene edited iPSCs demonstrated the variant reduced SMAD3 expression, senescence and inflammation in endothelial cells. In addition, heterozygosity in SMAD3 improved healthspan and reduced senescence in the Ercc1-/{Delta} progeroid mouse model of accelerated aging. Taken together, these experiments demonstrate that variants in a cell type specific enhancer of SMAD3 resulted in reduced expression, senescence and inflammation and contributes to human longevity. Thus, SMAD3 represents a validated targeted for drug development for extending human healthspan.

genetics↗

bioRxiv2022

A systems biology-based identification and in vivo functional screening of Alzheimer's disease risk genes reveals modulators of memory function

Genome-wide association studies (GWAS) have uncovered over 40 genomic loci associated with risk for late-onset Alzheimers Disease (LOAD), but identification of the underlying causal genes remains challenging. While the role of glial biology in the mediation of LOAD genetic risk has been increasingly recognized, recent studies of induced pluripotent stem cell (iPSC)-derived neurons from LOAD patients have demonstrated the existence of neuronal cell-intrinsic functional defects, absent interactions with other brain cell types or exposure to neurotoxic insults. Here, we searched for genetic contributions to neuronal dysfunction in LOAD pathobiology, using an integrative systems approach that incorporated multi-evidence-based gene-mapping and network analysis-based prioritization. We found widespread dysfunction in neuronal gene co-expression networks in the LOAD brain and identified synaptic and endolysosomal function as being specifically impacted by LOAD-associated genetic variation. A systematic perturbation screening of candidate risk genes in C. elegans revealed that neuronal knockdown of the LOAD risk gene orthologs vha-10 (ATP6V1G2), cmd-1 (CALM3), amph-1 (BIN1), ephx-1 (NGEF), and pho-5 (ACP2) significantly alters short/intermediate-term memory function, the cognitive domain affected earliest during LOAD progression. These results highlight the impact of LOAD risk genes on evolutionarily conserved memory function, as mediated through neuronal endosomal dysfunction, and identify new targets for further mechanistic interrogation.

genetics↗