Pleiotrophin (PTN): Multifunctional Regulation and Therapeutic Potential in The Nervous System
- VernacularTitle:多效生长因子在神经系统中的多功能调控与治疗潜力
- Author:
Xin TIAN
1
;
Zhen ZHANG
1
;
Fu-Cheng LUO
1
;
Tao LÜ
2
Author Information
- Publication Type:Journal Article
- Keywords: pleiotrophin (PTN); neurodegeneration; neuroinflammation; PTPRZ1; myelin
- From: Progress in Biochemistry and Biophysics 2026;53(3):550-563
- CountryChina
- Language:Chinese
- Abstract: Neurological disorders, including Alzheimer’s disease (AD), Parkinson’s disease (PD), cerebral ischemia, and multiple sclerosis (MS), impose an escalating global health burden and remain largely incurable. These disorders arise from multifactorial and interconnected pathological processes, such as chronic neuroinflammation, oxidative stress, protein misfolding and aggregation, demyelination, and neurovascular dysfunction. Despite substantial advances in elucidating disease-associated molecular mechanisms, current therapeutic strategies are predominantly symptomatic and fail to effectively halt or reverse disease progression. This limitation highlights the urgent need to identify endogenous regulatory molecules capable of coordinating neuronal survival, synaptic maintenance, inflammatory control, and tissue repair within the central nervous system (CNS). Pleiotrophin (PTN) is a heparin-binding, growth-associated cytokine that has emerged as a key regulator of neural development, plasticity, and regeneration. Structurally, PTN contains multiple high-affinity heparin-binding domains that facilitate interactions with extracellular matrix components and cell surface proteoglycans, enabling spatially restricted and context-dependent signaling. Through these molecular properties, PTN functions as a multifunctional organizer of neural growth, plasticity, and tissue remodeling across developmental and adult stages. Its diverse biological effects are executed through a multi-receptor signaling system that integrates extracellular cues with intracellular programs governing cellular survival, migration, and differentiation. Notably, PTN displays a highly dynamic and cell type-specific expression pattern in the central nervous system, being enriched in neural progenitor cells during development and later restricted to discrete neuronal populations, neural stem cells, and non-neuronal niche cells—including astrocytes, pericytes, and vascular endothelial cells—which serve as critical sources of PTN under physiological and pathological conditions. PTN expression is tightly regulated during development and exhibits pronounced plasticity in response to pathological stimuli. Under physiological conditions, PTN is transiently expressed during critical windows of neural growth and synaptogenesis, supporting neuron-glia interactions and myelin formation. In contrast, in pathological contexts such as amyloid β-protein (Aβ) accumulation in AD, dopaminergic neuron degeneration in PD, demyelination in MS, and ischemic brain injury, PTN expression is frequently dysregulated, suggesting an active role in disease-associated remodeling rather than a passive bystander effect. Importantly, accumulating evidence indicates that PTN exerts a dual and context-dependent influence on neurological disorders. On the one hand, aberrant PTN signaling may contribute to maladaptive responses, including sustained glial activation, dysregulated neuroinflammation, extracellular matrix remodeling, and enhanced Aβ deposition. On the other hand, PTN displays robust neuroprotective and reparative functions by promoting neuronal survival, enhancing oligodendrocyte maturation and remyelination, and stimulating post-injury angiogenesis, thereby facilitating tissue repair and functional recovery. At the mechanistic level, PTN signaling is characterized by extensive cross-talk among receptor-dependent pathways. Activation of anaplastic lymphoma kinase (ALK) triggers canonical PI3K-AKT-mTOR and MAPK cascades that support neuronal survival and axonal integrity. PTN binding to protein tyrosine phosphatase receptor type Z1 (PTPRZ1) induces conformational inhibition of its phosphatase activity, resulting in increased phosphorylation of downstream effectors such as β-catenin, Fyn, and Src, which regulate neuronal migration and synaptic stabilization. Syndecan-3 (SDC3) functions as both a co-receptor and an independent signaling mediator by capturing extracellular PTN, amplifying ALK- and PTPRZ1-dependent signaling, and directly modulating cytoskeletal dynamics through PKC and ERK pathways. In parallel, PTN interaction with αVβ3 integrin contributes to remodeling of the neurovascular niche, linking angiogenesis with neurogenesis and neural repair. From a translational perspective, therapeutic strategies targeting PTN can be broadly classified into 3 categories: direct enhancement of PTN signaling through exogenous protein supplementation or gene therapy-mediated upregulation, pharmacological modulation of PTN-associated receptor pathways and downstream signaling nodes, and exploitation of PTN as a dynamic biomarker to inform disease stratification and therapeutic responsiveness. These complementary approaches underscore the growing interest in PTN-centered interventions across a spectrum of neurological disorders. In summary, PTN functions not merely as a classical trophic factor but as a central signaling hub integrating inflammatory regulation, neural regeneration, and vascular remodeling within the CNS. This review aims to synthesize current insights into PTN’s molecular architecture, multi-receptor signaling mechanisms, and disease-specific functions, and to highlight emerging therapeutic strategies targeting PTN. By conceptualizing PTN as a dynamic modulator of neuronal resilience rather than a static biomarker, we propose that precise modulation of PTN signaling may offer promising avenues for therapeutic development in neurodegenerative and neuroinflammatory diseases.
