Blood Pressure Drug Diltiazem Shows Promise Against Childhood Dementia

A widely prescribed blood pressure medication may offer an unexpected lifeline for children battling one of the most devastating neurodegenerative diseases of childhood. New research published in the Journal of Molecular Medicine suggests that diltiazem, a calcium channel blocker used for decades to treat hypertension and angina, can suppress a destructive form of cell death known as parthanatos in cells from patients with juvenile neuronal ceroid lipofuscinosis, or JNCL. The findings, from a team at Hoseo University in South Korea, not only identify a druggable target for a disease that currently has no cure but also reveal an intricate molecular circuitry linking calcium signaling, DNA repair, and catastrophic cellular self-destruction.

Juvenile neuronal ceroid lipofuscinosis, also known as juvenile Batten disease, is caused by mutations in the CLN3 gene and represents a major form of juvenile dementia. Children with the condition typically develop vision loss in early childhood, followed by seizures, motor decline, and progressive cognitive deterioration, usually dying in their late twenties or thirties. The disease belongs to a family of lysosomal storage disorders in which cellular waste-processing machinery fails, leading to the accumulation of fatty waste materials called ceroid lipofuscin inside cells. Despite decades of research into the underlying genetics, effective therapies that slow the relentless neurodegeneration remain painfully out of reach.

The Korean team, led by Hyungkuen Kim, Eunmi Hwang, and Sung-Jo Kim, focused their investigation on parthanatos, a distinctive form of programmed cell death that has been extensively studied in Alzheimer’s disease but never before systematically characterized in JNCL. Parthanatos takes its name from poly(ADP-ribose), or PAR, a polymer produced by the enzyme PARP1. When cells experience excessive DNA damage, PARP1 becomes hyperactivated and floods the nucleus with PAR chains. These polymers eventually trigger the release of apoptosis-inducing factor from mitochondria, which migrates to the nucleus and orchestrates large-scale DNA fragmentation, killing the cell in a way that is distinct from classical apoptosis.

Using patient-derived lymphoblasts, immortalized white blood cells generated from JNCL patients, the researchers employed quantitative immunofluorescence microscopy to compare the disease cells with healthy controls. The results were striking. JNCL cells accumulated significantly higher levels of 8-oxoguanine, a pre-mutagenic DNA lesion produced when reactive oxygen species attack guanine bases, as well as elevated levels of PAR, the molecular signature of parthanatos. The accumulation of 8-oxoguanine is particularly insidious because it impairs DNA repair pathways, creating a vicious cycle in which oxidative damage begets repair failure, which begets further PARP1 overactivation and ultimately cell death.

The mechanistic logic connecting these observations to calcium is central to the study. JNCL is known to exhibit elevated intracellular calcium levels, a disturbance that has been documented in previous work on CLN3-deficient cells. Calcium overload is a well-established activator of PARP1, and studies in cardiomyocytes and other cell types have shown that calcium influx can directly stimulate PAR polymer production. In JNCL, this calcium-PARP1 axis appeared to be running unchecked, pushing vulnerable cells toward the parthanatos threshold. The researchers reasoned that if excess calcium was fueling the PARP1 fire, then dampening calcium entry might extinguish it.

Enter diltiazem. This L-type calcium channel blocker, which has been on pharmacy shelves since the 1970s, works by blocking voltage-gated calcium channels in heart and vascular smooth muscle. When the team treated JNCL patient-derived lymphoblasts with diltiazem, PAR accumulation dropped markedly. Critically, the protective effect persisted even when the cells were simultaneously exposed to a calcium ionophore, a chemical that forcibly floods cells with calcium. This suggested that diltiazem was not merely plugging calcium channels at the membrane but was intervening in the downstream signaling cascade that translates calcium excess into PARP1 activation, suppressing the expression of PARP1 itself and thereby limiting the raw material for parthanatos.

The drug’s benefits did not stop there. Diltiazem also reduced the accumulation of 8-oxoguanine in the JNCL cells, though intriguingly, this effect appeared to be largely independent of its calcium-blocking activity. Subcellular fractionation followed by immunoblotting, a technique that separates cellular compartments and identifies which proteins reside where, revealed that diltiazem enhanced the nuclear recruitment of OGG1, the primary enzyme responsible for excising 8-oxoguanine from DNA, along with its partner proteins. In other words, the drug was not just reducing the damage signal but was actively bolstering the cell’s repair crew, delivering the fix-it enzymes to the nucleus where the oxidative lesions accumulate.

To confirm that OGG1 was genuinely central to the drug’s protective mechanism, the researchers performed knockdown experiments, silencing the OGG1 gene in the treated cells. The results were unambiguous: when OGG1 was removed, diltiazem’s protective effects vanished entirely. This dependency establishes a dual role for the drug, acting simultaneously on calcium signaling to suppress PARP1 expression and on the OGG1-dependent base excision repair pathway to clear oxidative DNA damage. The finding also underscores a broader biological principle that has emerged from studies in Alzheimer’s disease and aging: OGG1-initiated repair is a double-edged sword, essential for genome maintenance but capable of exacerbating parthanatos when repair intermediates overstimulate PARP1.

The therapeutic implications are considerable. Diltiazem is an approved, well-characterized medication with decades of clinical safety data, which means that repurposing it for JNCL could potentially bypass some of the lengthy development timelines that plague novel drug candidates. Previous studies have already hinted at the drug’s relevance to neurodegeneration, with earlier work showing that L-type calcium channel blockers significantly lower intracellular calcium in CLN3-deficient neuroblastoma cells, and animal research demonstrating protective effects of diltiazem in chemically induced dementia models in mice. The new study adds a specific molecular mechanism, parthanatos suppression via PARP1 and OGG1 modulation, to this growing body of evidence.

Significant caveats remain before patients can benefit. The current findings derive from patient-derived lymphoblasts, which are accessible but imperfect proxies for the neurons that actually die in JNCL, and the researchers note that their data identify parthanatos as a novel therapeutic target rather than a validated clinical intervention. Whether diltiazem can cross the blood-brain barrier at sufficient concentrations, whether it will slow neurodegeneration in living organisms, and what dosing regimens would be appropriate for children all require further study. Nevertheless, by pinpointing PAR accumulation as a hallmark of JNCL pathology and demonstrating that an existing cardiovascular drug can interrupt this deadly cascade at two distinct points, the Hoseo University team has given the Batten disease research community something it has long needed: a concrete, pharmacologically tractable target in a disease where hope has been in short supply.

Subject of Research: Parthanatos and DNA repair dysfunction in juvenile neuronal ceroid lipofuscinosis and its modulation by the calcium channel blocker diltiazem

Article Title: The calcium channel blocker diltiazem ameliorates parthanatos in juvenile neuronal ceroid lipofuscinosis

Article References: Kim, H., Hwang, E., & Kim, S.-J. (2026). The calcium channel blocker diltiazem ameliorates parthanatos in juvenile neuronal ceroid lipofuscinosis. Journal of Molecular Medicine, 104(1), Article 118. https://doi.org/10.1007/s00109-026-02726-1

Image Credits: AI Generated

DOI: 10.1007/s00109-026-02726-1

Keywords: juvenile neuronal ceroid lipofuscinosis, Batten disease, CLN3, parthanatos, PARP1, diltiazem, 8-oxoguanine, OGG1, calcium signaling, DNA repair, drug repurposing, neurodegeneration