An RNA Eraser Gone Rogue: ALKBH5 Emerges as a Molecular Driver of Preeclampsia

Preeclampsia remains one of the most feared complications of pregnancy, a condition that strikes without warning, endangers two lives at once, and still defies a complete molecular explanation. Characterized by newly onset hypertension and often organ damage after the twentieth week of gestation, it affects a substantial proportion of pregnancies worldwide and stands among the leading causes of maternal and perinatal mortality. The placenta sits at the center of the disease: when the specialized cells called trophoblasts fail to invade and remodel the maternal vasculature properly, the placenta becomes under-perfused, oxidative stress mounts, and a cascade of maternal symptoms follows. Yet despite decades of research, the precise molecular switches that disable trophoblast function have remained frustratingly elusive. Now, a team of researchers at the Key Laboratory of Maternal and Fetal Medicine of the National Health Commission of China, based at the Shandong Provincial Maternal and Child Health Care Hospital affiliated with Qingdao University, has uncovered a surprising culprit operating at the level of RNA chemistry rather than DNA sequence.

The new study, published as an open-access original article in Cellular and Molecular Life Sciences, focuses on a chemical tag known as N6-methyladenosine, or m6A, the most abundant internal modification found in messenger RNA molecules across eukaryotic cells. Far from being decorative, m6A marks act as a dynamic layer of gene regulation: they influence how efficiently a transcript is translated into protein, how long it survives before being degraded, and even where it localizes within the cell. Writers install the mark, readers interpret it, and erasers remove it. The enzyme at the heart of the new findings, alkylation repair homolog protein 5, better known as ALKBH5, belongs to this last category. It is a demethylase, an enzyme that chemically strips m6A marks from RNA, and previous work had implicated it in everything from spermatogenesis to cancer progression. Whether it played any role in the diseased placenta, however, was unknown.

To find out, the researchers began where the disease begins: in placental tissue. Analyzing clinical samples from patients with preeclampsia, they discovered that ALKBH5 was consistently upregulated in the placentas of affected mothers compared with healthy pregnancies. Crucially, this overabundance of the demethylase coincided with a global decrease in m6A levels across placental transcripts, exactly what one would expect if an RNA eraser were working overtime. The same pattern appeared in a mouse model of preeclampsia-like disease, strengthening the case that the observation was not a human-tissue artifact but a reproducible feature of the disorder. The correlation, while compelling, left open the central question of causation: was ALKBH5 merely a bystander in the stressed placenta, or was it actively driving the pathology?

The team turned to a laboratory workhorse to answer that question. HTR8/SVneo cells, an immortalized human trophoblast line widely used to model placental cell behavior, were exposed to hydrogen peroxide to induce oxidative stress, mimicking the hostile environment that trophoblasts face in a preeclamptic placenta. As anticipated, the stressed cells lost their ability to invade and migrate, the very functions that healthy trophoblasts must perform to anchor the placenta and remodel maternal spiral arteries. But when the researchers knocked down ALKBH5 using small interfering RNA, the damage was partially reversed. The treated cells recovered a significant portion of their invasive and migratory capacity, suggesting that ALKBH5 was not simply responding to stress but actively contributing to the functional collapse of trophoblasts under oxidative assault.

With a functional link established, the next challenge was to identify the molecular target through which ALKBH5 exerted its effects. The researchers performed an integrated bioinformatics analysis, cross-referencing the RM2Target database with Gene Expression Omnibus datasets to search for genes that were both regulated by ALKBH5 and relevant to trophoblast biology. The search converged on a single compelling candidate: formyl peptide receptor 2, or FPR2, a G-protein-coupled receptor known to participate in inflammatory signaling. Subsequent validation experiments, including RNA immunoprecipitation and dual-luciferase reporter assays, confirmed that ALKBH5 physically and functionally interacts with FPR2 messenger RNA, establishing FPR2 as a bona fide downstream target of the demethylase.

The mechanistic details that emerged are elegant and, in the context of pregnancy disease, genuinely novel. ALKBH5 binds to the 3′ untranslated region of the FPR2 transcript, the stretch of RNA that follows the protein-coding sequence and typically governs transcript stability. By erasing m6A marks at this location, ALKBH5 stabilizes the FPR2 mRNA, allowing it to persist longer in the cell and driving up the production of the FPR2 receptor protein. In other words, the demethylase does not change the genetic message itself; it changes how long the message survives, and in doing so it amplifies a receptor that ultimately undermines trophoblast behavior. This m6A-dependent stabilization mechanism illustrates how epitranscriptomic regulation, a field barely two decades old, can produce consequences as dramatic as a pregnancy disorder.

The functional experiments sealed the argument. When the researchers overexpressed FPR2 in trophoblasts that had been protected by ALKBH5 knockdown, the protective effect vanished: the cells once again lost their invasive and migratory prowess under oxidative stress. FPR2, it appeared, was the executioner carrying out the damage that ALKBH5 had set in motion. Conversely, when the team administered WRW4, a pharmacological antagonist of FPR2, to mice with preeclampsia-like features, the disease phenotype improved. The antagonist ameliorated the key characteristics of the disorder in the animal model, providing proof of principle that blocking the receptor downstream of ALKBH5 can counteract the pathological process in a living system.

Taken together, the findings define what the authors describe as an ALKBH5–FPR2 axis in preeclampsia pathogenesis: an RNA-erasing enzyme upregulated in the diseased placenta strips methylation marks from FPR2 transcripts, prolongs their half-life, boosts receptor expression, and thereby disrupts the trophoblast functions on which a healthy pregnancy depends. The chain of evidence runs from human placental tissue through cell culture under oxidative stress to a mouse model and back again, with pharmacological rescue at the endpoint. Few studies of preeclampsia have traced a causal pathway with this degree of molecular resolution, and the identification of an epitranscriptomic mechanism in the disorder opens a fresh dimension in a field long dominated by angiogenic factors and immune hypotheses.

The therapeutic implications are tantalizing, though tempered by the usual caveats of early-stage research. Both nodes of the axis offer potential points of intervention: inhibiting ALKBH5 activity or blocking FPR2 signaling with agents such as WRW4 could, in theory, restore trophoblast function before the maternal syndrome takes hold. Because FPR2 already has known pharmacological modulators, the receptor represents a particularly attractive druggable target, and repurposing efforts could accelerate translation. Yet significant hurdles remain. The mouse model recapitulates preeclampsia-like features but not the full human disease, the precise timing and cell types in which the axis operates during human placentation require further mapping, and any intervention in pregnancy demands an exceptionally high safety bar. Still, the study adds a powerful new concept to the preeclampsia literature: that the fate of a pregnancy may hinge not on which genes are present, but on how long their RNA messages endure. As m6A biology continues to reshape our understanding of human disease, the placenta has now joined the list of organs where the epitranscriptome writes, and erases, the story of health.

Subject of Research: The role of the m6A demethylase ALKBH5 and its downstream target FPR2 in the pathogenesis of preeclampsia

Article Title: ALKBH5 contributes to preeclampsia through m6A-dependent upregulation of FPR2

Article References: Fan, C., Zhang, C., Liu, L., & Zhang, M. (2026). ALKBH5 contributes to preeclampsia through m6A-dependent upregulation of FPR2. Cellular and Molecular Life Sciences. https://doi.org/10.1007/s00018-026-06471-z

Image Credits: AI Generated

DOI: 10.1007/s00018-026-06471-z

Keywords: preeclampsia, ALKBH5, FPR2, m6A, RNA methylation, epitranscriptomics, trophoblast, placenta, oxidative stress, RNA stability, pregnancy, molecular biology