FGL

preclinical

Also known as: FG Loop peptide, FGL(L)

**Mechanism of Action** FGL (FG Loop peptide) is a synthetic peptide derived from the neural cell adhesion molecule (NCAM) that mimics the FG loop region of NCAM’s fibronectin type III domain. It selectively binds to and activates fibroblast growth factor receptor 1 (FGFR1), initiating downstream signaling cascades such as MAPK/ERK and PI3K/Akt pathways. This activation promotes neurite outgrowth, synaptogenesis, and long-term potentiation (LTP), thereby enhancing synaptic plasticity and memory consolidation in preclinical models. **Key Research Findings** Preclinical studies demonstrate that FGL improves spatial learning and memory in rodent models of aging and neurodegeneration, including Alzheimer’s disease. It reduces amyloid-beta pathology and tau hyperphosphorylation while increasing hippocampal neurogenesis. FGL also shows neuroprotective effects against excitotoxicity and oxidative stress. However, its short half-life and limited blood-brain barrier penetration remain challenges for translational development. **Clinical Relevance** FGL is in preclinical development as a potential therapeutic for cognitive decline associated with neurodegenerative disorders. Its ability to enhance synaptic plasticity and neuroprotection positions it as a candidate for conditions like Alzheimer’s disease and age-related memory impairment. No human trials have been conducted to date. For research purposes only — not medical advice.

Key data

Category
Cognitive & Neuroprotective
Administration
intranasal, subcutaneous
Research status
preclinical
References
260
Tags
ncam, synaptic-plasticity

Research & studies

Regulatory Role of FGL-1 in Interorgan Communication by Controlling T Cell Homeostasis During the Onset of Sjögren Disease
Arthritis & rheumatology (Hoboken, N.J.) · 2025 · PubMed

FGL-1 is a potent factor for interorgan communication between the liver and immune system in primary Sjögren disease.; Liver FGL-1 production is induced by interleukin-6 from CD4+ T cells.; Fgl1-deficient mice show earlier onset of autoimmune lesions compared to wild-type mice.; FGL-1 levels are significantly elevated in patients with primary Sjögren disease and correlate with serum IL-6 levels.

Integrated molecular and clinical characterization of pulmonary large cell neuroendocrine carcinoma
Nature communications · 2025 · PubMed

Comparable overall survival across chemotherapy, chemoimmunotherapy, and immunotherapy regimens without unexpected adverse events.; Genomic analysis reveals NSCLC-like (KEAP1, KRAS, STK11) and SCLC-like (RB1, TP53) LCNEC subtypes, with 80% aligning with SCLC transcriptional profiles.; Elevated FGL-1 and SPINK1 expression in NSCLC-like LCNECs, and higher DLL3 levels in SCLC-like LCNECs.; Fewer tumor-infiltrating lymphocytes in LCNECs compared to other lung cancers.

Effects of Bioconverted Guava Leaf (Psidium guajava L.) Extract on Skeletal Muscle Damage by Regulation of Ubiquitin-Proteasome System and Apoptosis in Type 2 Diabetic Mice
International journal of molecular sciences · 2025 · PubMed
Pan-cancer single-cell analysis reveals the heterogeneity and plasticity of cancer-associated fibroblasts in the tumor microenvironment
Nature communications · 2022 · PubMed

Major CAF types exhibit three activation states with distinct interactions and prognostic relevance for immunotherapy.; Minor CAF components can originate from other TME components such as endothelia and macrophages.; Endothelial-to-mesenchymal transition CAFs are ubiquitously present and may interact with SPP1+ tumor-associated macrophages, impacting survival.

Moderated Network Models
Multivariate behavioral research · 2021 · PubMed

The GGM assumption of independent pairwise interactions is often implausible in psychological research.; MNMs allow each pairwise interaction to be moderated by a subset of other variables in the model.; Simulations show MNMs outperform split-sample methods (NCT and FGL) for detecting moderation effects.; The R-package mgm provides a reproducible tutorial for estimating MNMs.

Role of placental fibrinogen-like protein 1 in gestational diabetes
Translational research : the journal of laboratory and clinical medicine · 2020 · PubMed
NCAM Mimetic Peptides: Potential Therapeutic Target for Neurological Disorders
Neurochemical research · 2018 · PubMed
Peptides Acting as Cognitive Enhancers
Neuroscience · 2018 · PubMed

FGL peptide improves cognition by activating PKC pathway, leading to AMPA receptor delivery to synapses.; PTD4-PI3KAc peptide enhances hippocampal memory by promoting synapse and spine formation via PI3K signaling.; PTEN-derived peptide prevents memory deterioration in Alzheimer's mouse model by blocking pathological PTEN-PDZ interactions.; Synaptic function is a valid target for cognitive enhancement through peptide treatment.

Frequently asked questions

What is FGL?

**Mechanism of Action** FGL (FG Loop peptide) is a synthetic peptide derived from the neural cell adhesion molecule (NCAM) that mimics the FG loop region of NCAM’s fibronectin type III domain. It selectively binds to and activates fibroblast growth factor receptor 1 (FGFR1), initiating downstream signaling cascades suc

How does FGL work?

NCAM-derived FG-loop peptide that activates FGFR1 to enhance synaptic plasticity and memory in animal models.

What is the research status of FGL?

FGL is currently classified as preclinical, with 260 research references on record. This is for research purposes only and is not medical advice.

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