SP1/ADAM10/DRP1 Axis in Hypoxia-Induced Pulmonary Hypertensi

2026-07-17

SP1/ADAM10/DRP1 Axis in Hypoxia-Induced Pulmonary Hypertension

Study Background and Research Question

Hypoxia pulmonary hypertension (HPH) is a severe complication of chronic lung diseases, including chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF), characterized by elevated pulmonary artery pressure and progressive vascular remodeling. Endothelial cell (EC) and smooth muscle cell (SMC) interactions are central to this remodeling process, but the molecular mediators of their crosstalk in hypoxic conditions remain incompletely defined. The reference study (Li et al., 2025) investigates whether the SP1/ADAM10/DRP1 signaling axis and its downstream pathways mediate EC-SMC communication under hypoxic stress—ultimately influencing SMC proliferation, apoptosis, and pulmonary artery remodeling in HPH.

Key Innovation from the Reference Study

The major innovation presented by Li et al. is the identification of a SP1/ADAM10/DRP1 axis that functionally links hypoxia-exposed ECs to SMC phenotype regulation. This axis comprises transcriptional upregulation of ADAM10 by the transcription factor SP1 in hypoxic ECs, increased ADAM10 secretion, and subsequent activation of DRP1-dependent mitochondrial dynamics in SMCs. By dissecting this pathway, the study reveals how mitochondrial fission, regulated by DRP1, contributes to the proliferation and apoptosis resistance of SMCs—key events in pulmonary vascular remodeling. ADAM10 thus emerges as both a paracrine effector and a potential upstream switch for mitochondrial outer membrane permeabilization (MOMP) and apoptosis regulation in SMCs.

Methods and Experimental Design Insights

The study employed a combination of in vivo and in vitro approaches:

Hypoxia-induced pulmonary hypertension was modeled in rats, with pulmonary artery pressures and histopathology assessed to confirm disease induction.
Primary cultured pulmonary artery ECs and SMCs were subjected to hypoxic conditions. Expression of ADAM10, DRP1, and related signaling proteins was analyzed by Western blot and qPCR.
Conditioned media from ECs (with or without ADAM10 knockdown or overexpression) were applied to SMC cultures to study paracrine effects on SMC proliferation and apoptosis, including apoptosis assays and proliferation markers.
Pharmacological inhibition using Mdivi-1 (a selective DRP1 inhibitor) and LY294002 (PI3K inhibitor) was applied to SMCs to dissect the relative contributions of mitochondrial fission and PI3K/AKT/mTOR signaling.
Bioinformatic prediction (JASPAR database) and molecular assays confirmed SP1 as a transcriptional regulator of ADAM10 in hypoxic ECs.

This multifaceted design allowed the authors to interrogate both cell-intrinsic and paracrine mechanisms and to link transcriptional events with mitochondrial dynamics and cell fate decisions.

Core Findings and Why They Matter

The reference study's principal findings are:

ADAM10 is upregulated in hypoxia-exposed ECs and in rat models of HPH. Knockdown of ADAM10 in ECs alleviates HPH phenotypes in rats and reduces the malignant features of hypoxic ECs.
Conditioned media from hypoxic ECs promote SMC proliferation and apoptosis resistance, effects that are significantly reduced when ADAM10 is silenced in ECs.
SMCs exposed to ADAM10-rich conditioned media display increased DRP1, PI3K, AKT, and mTOR protein levels, implicating both mitochondrial dynamics and classic signaling pathways in phenotype modulation.
Pharmacologic inhibition of DRP1 using Mdivi-1 reverses the pro-proliferative, anti-apoptotic effects of ADAM10-rich media on SMCs, highlighting the functional role of mitochondrial fission in this context.
SP1 transcriptionally drives ADAM10 expression in hypoxic ECs, establishing the upstream regulatory framework of this intercellular axis.

Collectively, these results provide strong evidence that the SP1/ADAM10/DRP1 axis is a critical regulator of EC–SMC communication under hypoxic stress—a central event in the pathogenesis of HPH. By linking mitochondrial fission directly with cell fate in pulmonary vascular remodeling, the study opens new avenues for targeted intervention in diseases marked by aberrant mitochondrial dynamics.

Comparison with Existing Internal Articles

The mechanistic insights from this study align closely with multiple recent reviews and protocols centered on mitochondrial dynamics and DRP1 inhibition:

The internal article "SP1/ADAM10/DRP1 Axis in Hypoxia Pulmonary Hypertension Crosstalk" independently highlights the significance of DRP1 as a signaling hub in EC–SMC interactions and corroborates the potential of selective DRP1 inhibition to modulate pulmonary vascular remodeling.
For researchers interested in technical application, "Applied Mdivi-1: Protocols for Selective DRP1 Inhibition in Mitochondrial Dynamics" offers workflow-driven guidance for Mdivi-1 use in both cell-based and animal models of pulmonary hypertension, complementing the reference study's experimental approach.
Furthermore, "Mdivi-1: Selective DRP1 Inhibitor for Mitochondrial Dynamics" elaborates on the compound’s mechanism and showcases its utility in apoptosis assays and neuroprotection, thus providing background for interpreting DRP1-targeted results in the pulmonary vascular context.

These resources reinforce the translational relevance of DRP1 as a target and support the reference study’s methodological choices.

Limitations and Transferability

Despite its strengths, the study has several limitations. The in vivo component is restricted to a single animal model of hypoxia-induced hypertension, which may not fully capture the heterogeneity of human pulmonary vascular disease. While the use of conditioned media elegantly demonstrates paracrine signaling, the precise cargo (e.g., extracellular vesicles, soluble factors) responsible for transmitting ADAM10’s effects remains to be further dissected. The reliance on pharmacological inhibition, though informative, may be subject to off-target effects; thus, complementary genetic approaches could strengthen causal inference. Finally, while ADAM10 and DRP1 appear central to EC–SMC crosstalk under hypoxia, transferability to other vascular beds or disease contexts awaits further study.

Protocol Parameters

Mdivi-1 treatment (cell-based assays): 50 μM, added to SMC cultures for 24–48 hours to inhibit DRP1-mediated mitochondrial fission, as demonstrated in the reference study and protocol resources.
Mdivi-1 administration (in vivo studies): 50 mg/kg intraperitoneally, typically administered daily in rodent models of HPH to assess effects on vascular remodeling and cell apoptosis.
Conditioned medium preparation: Collect supernatant from hypoxic ECs or ECs with manipulated ADAM10 expression after 24–48 hours; filter before use in SMC cultures.
Apoptosis assay timing: Assess SMC apoptosis 24–48 hours after exposure to conditioned medium and/or pharmacological inhibitors.
Gene knockdown/overexpression: Use validated siRNA or expression vectors for ADAM10 and SP1; confirm efficiency by Western blot or qPCR prior to downstream assays.

These parameters reflect both the literature evidence and practical recommendations for those establishing similar experimental workflows.

Research Support Resources

For researchers aiming to investigate mitochondrial dynamics, apoptosis, and vascular remodeling, selective DRP1 inhibitors remain essential tools. Mdivi-1 (SKU A4472, APExBIO) is widely applied for this purpose, offering high selectivity and compatibility with both cell-based and animal models. Its use is well-established in protocols analyzing mitochondrial fission, apoptosis, and neuroprotection, as detailed in the product information and recent workflows. Researchers can reference these resources to optimize mitochondrial dynamics research and related apoptosis assays, particularly in the context of hypoxia-induced pulmonary vascular disease.