HK2-mediated augmentation of endothelial cell glycolysis promotes placental vascular disorders through lactylation and pyroptosis

Abstract

Preeclampsia (PE) involves complex metabolic-inflammatory interactions, yet the mechanistic links among glycolysis, protein lactylation, and pyroptosis in placental pathogenesis remain undefined. In this study, we explore their tripartite relationship with PE development by combining bioinformatics analysis of PE-associated transcriptomes with experimental validation using placental tissues from PE patients and healthy controls. To elucidate the underlying mechanism, we utilize in vitro models involving hypoxic endothelial cell cultures, pharmacological glycolysis inhibition via 2-deoxyglucose, and genetic modulation of hexokinase 2 (HK2) expressions through siRNA silencing and plasmid-based overexpression. Molecular profiling is used to assess the expressions of key glycolytic enzymes, lactylation markers, and pyroptosis-related factors. Compared with control placental tissues, PE placental tissues present significantly higher expressions of glycolytic enzymes, elevated protein lactylation levels, and increased pyroptosis markers. Similarly, hypoxic endothelial cells exhibit coordinated upregulation of these three pathways. Notably, pharmacological glycolysis inhibition significantly reduces both lactylation and pyroptosis levels. Genetic experiments further demonstrate that HK2 silencing decreases glycolytic activity, subsequently attenuating lactylation and pyroptosis, whereas HK2 overexpression has opposite effects, underscoring its central regulatory role in this metabolic-inflammatory axis. Collectively, these findings indicate that HK2-mediated glycolysis drives placental vascular endothelial lactylation and pyroptosis, revealing a novel mechanistic pathway in PE pathophysiology.

1. Introduction

Preeclampsia (PE) is a prevalent and clinically distinct multisystem syndrome that manifests during pregnancy and is characterized primarily by hypertension and proteinuria [1,2]. As a major obstetric complication, PE contributes greatly to maternal and neonatal morbidity and mortality, affecting approximately 2%–8% of pregnancies worldwide [3]. Beyond its clinical severity, PE imposes substantial economic and societal burdens, further underscoring the urgency of understanding its pathogenesis [4]. Although placental dysfunction is widely recognized as a central driver of PE, the precise molecular mechanisms involved remain incompletely understood [5]. Consequently, unravelling the pathophysiological complexity of PE remains an important challenge in contemporary biomedical research.

Metabolic dysregulation, particularly anomalies in glycolytic metabolism, has emerged as a critical contributor to PE pathogenesis. Dysfunctional glycolysis may impair placental development, blastocyst implantation, and trophoblast invasion, all of which are crucial for healthy pregnancy progression [6–8]. These metabolic perturbations coincide with systemic inflammation, antiangiogenic factor imbalances, and endothelial dysfunction, all of which are hallmarks of the clinical manifestations of PE [9,10]. Intriguingly, our Pearson correlation analysis revealed that hexokinase 2 (HK2), a key glycolytic enzyme, is the most strongly correlated gene among the differentially expressed genes in PE. HK2 catalyzes the first committed step of glycolysis and is indispensable in cellular energy metabolism, particularly in highly proliferative cells such as endothelial cells [11]. Its overexpression is associated with the Warburg effect, a metabolic reprogramming phenomenon favoring aerobic glycolysis even under normoxic conditions [12,13]. Given these results, we hypothesize that HK2-mediated glycolytic dysregulation in placental vascular endothelial cells may be a critical factor in the development of PE, warranting further investigation.

A key consequence of increased glycolysis is the accumulation of lactate, a metabolic byproduct that increases under hypoxic conditions [14]. In addition to being an energy substrate, lactate is a precursor for protein lactylation, a novel posttranslational modification that influences gene expression by modulating histone and nonhistone protein function [15,16]. Notably, PE placental tissues exhibit elevated lactate levels and increased histone lactylation, with hypoxia further exacerbating lactate production in trophoblast models (HTR-8/SVneo and TEV-1 cells) [17]. Similarly, glycolysis-driven lactylation has been implicated in cardiovascular diseases and cancer, where it perpetuates endothelial dysfunction and inflammatory responses [18–20]. However, whether lactylation contributes to placental endothelial dysfunction in PE remains unexplored, indicating a critical knowledge gap.