Unlocking the Mystery of Pulmonary Hypertension: How HMGB1 Holds the Key
"New research reveals the critical role of HMGB1 in the development of pulmonary hypertension, offering potential new targets for treatment and prevention."
Pulmonary hypertension (PH) is a devastating disease characterized by the narrowing of pulmonary arteries, leading to right heart failure and ultimately, death. While the exact causes of PH remain elusive, inflammation and the mobilization of intracellular calcium are known contributors. High-mobility group box 1 (HMGB1), a DNA chaperone with diverse cellular functions, has recently emerged as a critical player in PH development.
HMGB1, traditionally known for its role in DNA repair and replication within the cell nucleus, takes on a different persona when it ventures outside. Released into the cytoplasm or extracellular space, HMGB1 acts as a damage-associated molecular pattern (DAMP), triggering a cascade of cellular responses, including inflammation and immunity. This dual nature of HMGB1 has sparked intense research into its role in various diseases, including pulmonary hypertension.
Recent studies have highlighted HMGB1's involvement in PH, with researchers exploring its potential as a therapeutic target. Now, a groundbreaking study sheds new light on the mechanistic importance of HMGB1 in pulmonary hypertension, revealing its intricate interplay with toll-like receptor 4 (TLR4), calcium signaling, and the Akt pathway. This discovery paves the way for novel strategies to combat this life-threatening condition.
HMGB1 in Pulmonary Hypertension
A clinical and in vivo pilot study examined high mobility group box 1 protein (HMGB1) as a biomarker in hypoxia-induced persistent pulmonary hypertension of the newborn. A study dated August 21, 2026, investigated the prognostic value of serum HMGB1 in people experiencing acute exacerbations of chronic obstructive pulmonary disease with concurrent pulmonary hypertension. Its stated rationale is that these combined conditions worsen outcomes while reliable prognostic biomarkers remain lacking.
Current Methods and Gaps
Pulmonary arterial hypertension can impair haemodynamics, right-heart function, exercise capacity, quality of life, and survival. Current therapies act through signalling involving one of four pathways. Contemporary guidance also emphasizes baseline and provocative invasive hemodynamic testing for accurate diagnosis, phenotyping, and management, while significant therapeutic gaps remain and few innovative therapies beyond traditional endothelial-dysfunction pathways have reached clinical-trial phases.
How Does HMGB1 Contribute to Pulmonary Hypertension?
The new research paper uncovers a cascade of events initiated by HMGB1 that leads to the progression of pulmonary hypertension. The study, conducted on rat models, reveals that HMGB1 levels surge in lung tissue and blood plasma following chronic hypoxia exposure and monocrotaline treatment, two common methods for inducing PH in animals. This surge prompts HMGB1 to translocate from the nucleus to the cytoplasm in pulmonary artery smooth muscle cells (PASMCs), a process seemingly mediated by the production of reactive oxygen species (ROS).
- HMGB1 Release: Increased levels of HMGB1 are observed in lung tissue and blood plasma under PH-inducing conditions.
- Cellular Translocation: HMGB1 moves from the nucleus to the cytoplasm in PASMCs.
- Calcium Mobilization: HMGB1 triggers calcium signaling within PASMCs.
- TLR4 and TRPC Involvement: This signaling is dependent on TLR4 and TRPC channels.
HMGB1, Glycolysis, and YAP
A 2025 study reported that HMGB1-treated pulmonary arterial smooth muscle cells showed significantly increased PFKFB3 expression and glycolysis. These changes were accompanied by dephosphorylation and nuclear translocation of Yes-associated protein (YAP) through Rho-associated protein kinase signalling. The findings connect HMGB1 exposure with cellular pathways involved in pulmonary arterial smooth muscle cell behavior in pulmonary arterial hypertension.
Implications for Future Therapies
These findings highlight the mechanistic importance of HMGB1 in pulmonary hypertension. By revealing its role in TLR4- and TRPC-associated calcium influx, and Akt phosphorylation-driven PASMC migration, this research identifies potential new targets for therapeutic intervention. Future research efforts should focus on developing HMGB1 inhibitors or strategies to disrupt its interaction with TLR4 and downstream signaling pathways. This could pave the way for more effective treatments for pulmonary hypertension.
A Potential Prognostic Signal
Research on acute exacerbations of chronic obstructive pulmonary disease with concurrent pulmonary hypertension describes serum HMGB1 as a potential tool for prognostic assessment. The reported work examined HMGB1's relationship with inflammatory and vascular markers, and another summary states that serum HMGB1 may aid risk assessment during acute exacerbations. Together, these reports support continued evaluation of HMGB1 as a clinically useful prognostic biomarker rather than treating its role as established.
Diagnostic Complexity and Disease Burden
Pulmonary hypertension associated with left heart disease is described as the most prevalent form of pulmonary hypertension and carries substantial morbidity and mortality risk. Diagnosis is challenging because phenotypes overlap, echocardiographic estimates can be imprecise, and clinicians may need invasive hemodynamic assessment. Against this background, HMGB1 has been reported as potentially critical to pulmonary hypertension development, although its underlying mechanism has not been fully revealed.