Thymosin Alpha-1 Provides Direct Neuroprotection by Engaging the Orexin Receptor HCRTR1 to Suppress Neuronal Necroptosis.

Mixed-methods study involving human observational cohort analysis and in vivo/in vitro animal experiments

“15 healthy donors and consecutive 28 AIS patients within 7 days of symptom onset were prospectively enrolled in the Third Affiliated Hospital of Sun Yat‐sen University from July 2024 to December 2025.”

Human acute ischemic stroke patients, healthy human donors, and male C57/Bl6 wild-type and Ptma+/− mice

“8‐12‐weeks‐old, male C57/Bl6 wild‐type mice were purchased from Guangdong Medical Laboratory Animal Center (Guangzhou, China).”

43 human participants (15 healthy controls, 28 AIS patients) and variable mouse cohorts (e.g., N=20 per group for survival, N=10 per group for infarct volume)

“Healthy control (HC) (N = 15) and AIS patients (N = 28) peripheral blood serum and clinical data were collected and subjected to further analysis.”

Human enrollment from July 2024 to December 2025; mouse experiments assessed at 3 and 14 days post-stroke with 14-day treatment period

“15 healthy donors and consecutive 28 AIS patients within 7 days of symptom onset were prospectively enrolled in the Third Affiliated Hospital of Sun Yat‐sen University from July 2024 to December 2025.”

Thymosin alpha-1 (Tα1) functions as a non-canonical ligand for the Hypocretin (Orexin) Receptor 1 (HCRTR1) on neurons

“We show that the thymus‐derived peptide Thymosin alpha‐1 (Tα1) functions as a non‐canonical ligand for the Hypocretin (Orexin) Receptor 1 (HCRTR1), a classical neuropeptide receptor on neurons.”

Tα1 engagement of HCRTR1 suppresses Receptor‐Interacting Protein Kinase 3 (RIPK3) activity, thereby inhibiting necroptosis and protecting neurons from cell death

“This engagement shields neurons from cell death by suppressing the activity of Receptor‐Interacting Protein Kinase 3 (RIPK3), a central executioner of necroptosis.”

Circulating Tα1 levels are significantly reduced in ischemic stroke patients and mice, correlating with disease severity, and genetic deletion of Ptma exacerbates stroke injury

“The physiological relevance of this pathway is highlighted in ischemic stroke, where we found that circulating Tα1 levels were significantly reduced in patients and mice, strongly correlating with disease severity.”

Use of heterozygous knockout mice instead of conditional models, need for validation in larger longitudinal human cohorts, and lack of comprehensive time-course analyses of immune cell populations

“The use of heterozygous knockout mice, while necessary, provides a conditional, cell‐specific knockout models would further refine our understanding of Tα1's role.”