Biology subjects

Ayer, A.

Publications and source records attributed to Ayer, A..

5 recordsLinked to original sources

bioRxiv2026

LIPC-E97G Gain-of-function variant potentiates the hypocholesterolemic and anti-atherogenic effects of evinacumab in Ldlr-/- mice

Introduction: Cardiovascular disease is the leading cause of death worldwide (Dagenais et al. 2020), and its main risk factor is LDL-C (Hagenbeek et al. 2020). Only a few genes are associated with LDL-C concentrations, and only 2 genes, ANGPTL3 (Musunuru et al. 2010) and LIPC, are associated with familial combined hypocholesterolemia. Our team recently identified the second genetic cause associated with familial combined hypocholesterolemia, a gain-of-function mutant of the LIPC gene encoding hepatic lipase (HL), LIPC-E97G (Dijk et al. 2022). Although the mode of action of this variant remains largely unknown, we have demonstrated that it significantly increases the phospholipase activity of HL and affects lipoprotein metabolism by promoting plasma cholesterol clearance, particularly of LDL and HDL. Objective: The aim of this study was to explore the additive effect of our HL-E97G variant with a pharmacological inhibitor of the ANGPTL3 protein, evinacumab, on cholesterolemia and atherosclerosis. Materiel and methods: Atherosclerosis measurements were performed on Ldlr-/- mice fed a pro-atherogenic diet. These mice received a single injection of a liver-targeting AAV8 expressing the wild-type or E97G human form of the LIPC gene (1.10E11 genome copies/mouse) and a weekly injection of NaCl or evinacumab (25 mg/kg/week). Results: From a therapeutic approach, we demonstrated a cumulative effect of HL-E97G with evinacumab. Atherosclerotic lesions in the aortic arch of Ldlr-/- mice were reduced by 36% (p=0.4897) with evinacumab, by 65% (p-value=0.0028) with HL-E97G, and by 80% (p-value < 0.0001) with the combined therapy. Conclusion: Our data demonstrate that HL-E97G reduces the development of atherosclerosis in mice in an LDLR- and ANGPTL3-independent manner, strongly reinforcing the therapeutic potential of HL-E97G for patients at high risk of cardiovascular disease.

physiology↗

bioRxiv2026

Genome-scale mapping of variant, enhancer and gene function in primary human CD4+ T cells

CD4+ T cells harbor a disproportionate enrichment of immune disease risk loci and represent the primary cellular context for immune disease biology, yet the genes and regulatory programs these variants affect remain largely unknown. We combined targeted Perturb-seq of 1,032 cis-regulatory elements (CREs) overlapping 4,724 variants across 14 immune diseases with genome-wide Perturb-seq of all expressed genes in primary human CD4+ T cells, spanning 4.1 million cells. We identified 626 CRE-gene pairs, and connected CRE targets to downstream regulatory cascades. At the TYK2 and DEXI/CLEC16A loci, we resolved target genes and linked noncoding variants to inflammatory and metabolic programs. Across diseases, we revealed that dispersed variants converged on shared and disease-specific programs. Our work provides a framework for tracing variant-to-CRE-to-gene-to-network in disease-relevant primary cells.

genetics↗

bioRxiv2023

PCSK9 inhibition protects mice from food allergy

The Proprotein Convertase Subtilisin Kexin of type 9 (PCSK9) has been identified in 2003 as the third gene involved in familial hypercholesterolemia. PCSK9 binds to the membrane low-density lipoprotein receptor (LDLR) and promotes its cellular internalization and lysosomal degradation. Beyond this canonical role, PCSK9 was recently described to be involved in several immune responses. However, to date, the contribution of PCSK9 in food allergy remains unknown. Here, we showed that Pcsk9 deficiency or pharmacological inhibition of circulating PCSK9 with a specific monoclonal antibody (m-Ab) protected mice against symptoms of gliadin-induced-food allergy, such as increased intestinal transit time and ear oedema. Furthermore, specific PCSK9 inhibition during the elicitation steps of allergic process was sufficient to ensure anti-allergic effects in mice. Interestingly, the protective effect of PCSK9 inhibition against food allergy symptoms was independent of the LDLR as PCSK9 inhibitors remained effective in Ldlr deficient mice. In vitro, we showed that recombinant gain of function PCSK9 (PCSK9 D374Y) increased the percentage of mature bone marrow derived dendritic cells (BMDCs), promoted naive T cell proliferation and potentiated the gliadin induced basophils degranulation. Altogether, our data demonstrate that PCSK9 inhibition is protective against gliadin induced food allergy in a LDLR-independent manner.

physiology↗

bioRxiv2021

Zebrafish heme oxygenase 1a is necessary for normal development and macrophage migration

Heme oxygenase function is highly conserved between vertebrates where it plays important roles in normal embryonic development and controls oxidative stress. Expression of the zebrafish heme oxygenase 1 genes are known to be responsive to oxidative stress suggesting a conserved physiological function. Here we generate a knockout allele of zebrafish hmox1a and characterize the effects of hmox1a and hmox1b loss on embryonic development. We find that loss of hmox1a or hmox1b causes developmental defects in only a minority of embryos, in contrast to Hmox1 gene deletions in mice that causes loss of most embryos. Using a tail wound inflammation assay we find a conserved role for hmox1a, but not hmox1b, in normal macrophage migration to the wound site. Together our results indicate zebrafish hmox1a has clearly a partitioned role from hmox1b that is more consistent with conserved functions of mammalian Heme oxygenase 1.

developmental biology↗

bioRxiv2020

Multiplex single-molecule kinetics of nanopore-coupled polymerases

DNA polymerases have revolutionized the biotechnology field due to their ability to precisely replicate stored genetic information. Screening variants of these enzymes for unique properties gives the opportunity to identify polymerases with novel features. We have previously developed a single-molecule DNA sequencing platform by coupling a DNA polymerase to a -hemolysin pore on a nanopore array. Here, we use this approach to demonstrate a single-molecule method that enables rapid screening of polymerase variants in a multiplex manner. In this approach, barcoded DNA strands are complexed with polymerase variants and serve as templates for nanopore sequencing. Nanopore sequencing of the barcoded DNA reveals both the barcode identity and kinetic properties of the polymerase variant associated with the cognate barcode, allowing for multiplexed investigation of many polymerase variants in parallel on a single nanopore array. Further, we develop a robust classification algorithm that discriminates kinetic characteristics of the different polymerase mutants. As a proof of concept, we demonstrate the utility of our approach by screening a library of ~100 polymerases to identify variants for potential applications of biotechnological interest. We anticipate our screening method to be broadly useful for applications that require polymerases with unique or altered physical properties.

synthetic biology↗