High levels of fatty acid-binding protein 5 excessively enhances fatty acid synthesis and proliferation of granulosa cells in polycystic ovary syndrome.

{"sci_version": "1.2", "schema": "https://corpus.bntrg.co.uk/sci/1.0/sci.schema.json", "id": "pmid:38373971", "kind": "science-record", "revision": 2, "content_hash": "sha256:804f7c66487a21fa50af624c13cf8159741295c81eda15e8e5cdaf2443823a46", "created_at": "2026-11-01T19:20:19Z", "updated_at": "2026-11-01T21:32:33Z", "generator": {"name": "corpus-assay-engine", "run_id": "reading-sci-2026-11-01"}, "paper": {"state": "complete", "title": "High levels of fatty acid-binding protein 5 excessively enhances fatty acid synthesis and proliferation of granulosa cells in polycystic ovary syndrome.", "doi": "10.1186/s13048-024-01368-6", "pmid": "38373971", "authors": ["Jingyu Liu", "Jie Li", "Xin Wu", "Mei Zhang", "Guijun Yan", "Haixiang Sun", "Dong Li"], "journal": "Journal of ovarian research", "year": 2024, "abstract": "BACKGROUND: Polycystic ovary syndrome (PCOS) is one of the most complex endocrine disorders in women of reproductive age. Abnormal proliferation of granulosa cells (GCs) is an important cause of PCOS. This study aimed to explore the role of fatty acid-binding protein 5 (FABP5) in granulosa cell (GC) proliferation in polycystic ovary syndrome (PCOS) patients.\nMETHODS: The FABP5 gene, which is related to lipid metabolism, was identified through data analysis of the gene expression profiles of GSE138518 from the Gene Expression Omnibus (GEO) database. The expression levels of FABP5 were measured by quantitative real-time PCR (qRT‒PCR) and western blotting. Cell proliferation was evaluated with a cell counting kit-8 (CCK-8) assay. Western blotting was used to assess the expression of the proliferation marker PCNA, and immunofluorescence microscopy was used to detect Ki67 expression. Moreover, lipid droplet formation was detected with Nile red staining, and qRT‒PCR was used to analyze fatty acid storage-related gene expression.\nRESULTS: We found that FABP5 was upregulated in ovarian GCs obtained from PCOS patients and PCOS mice. FABP5 knockdown suppressed lipid droplet formation and proliferation in a human granulosa-like tumor cell line (KGN), whereas FABP5 overexpression significantly enhanced lipid droplet formation and KGN cell proliferation. Moreover, we determined that FABP5 knockdown inhibited PI3K-AKT signaling by suppressing AKT phosphorylation and that FABP5 overexpression activated PI3K-AKT signaling by facilitating AKT phosphorylation. Finally, we used the PI3K-AKT signaling pathway inhibitor LY294002 and found that the facilitation of KGN cell proliferation and lipid droplet formation induced by FABP5 overexpression was inhibited. In contrast, the PI3K-AKT signaling pathway agonist SC79 significantly rescued the suppression of KGN cell proliferation and lipid droplet formation caused by FABP5 knockdown.\nCONCLUSIONS: FABP5 promotes active fatty acid synthesis and excessive proliferation of GCs by activating PI3K-AKT signaling, suggesting that abnormally high expression of FABP5 in GCs may be a novel biomarker or a research target for PCOS treatment.", "claims": [{"id": "claim-method", "statement": "Statistical significance was evaluated with a two-tailed unpaired t test.", "kind": "methodological", "target": null, "evidence": [{"asset": "source:pmid:38373971", "locator": "sections[16] \"Statistical analysis\" paragraph 2", "quote": "Statistical significance was evaluated with a two-tailed unpaired t test."}], "state": "complete"}, {"id": "claim-data-access", "statement": "We downloaded the gene expression profiles of GSE138518 from the GEO database (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE138518) [24]. The dataset included 3 PCOS ovarian granule cell samples and 3 normal samples.", "kind": "methodological", "target": null, "evidence": [{"asset": "source:pmid:38373971", "locator": "sections[3] \"Data collection\" paragraph 2", "quote": "We downloaded the gene expression profiles of GSE138518 from the GEO database (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE138518) [24]. The dataset included 3 PCOS ovarian granule cell samples and 3 normal samples."}], "state": "complete"}, {"id": "claim-target-result", "statement": "FABP5 promotes active fatty acid synthesis and excessive proliferation of GCs by activating PI3K-AKT signaling.", "kind": "qualitative", "target": null, "evidence": [{"asset": "source:pmid:38373971", "locator": "sections[0] \"Abstract\" paragraph 4", "quote": "FABP5 promotes active fatty acid synthesis and excessive proliferation of GCs by activating PI3K-AKT signaling, suggesting that abnormally high expression of FABP5 in GCs may be a novel biomarker or a research target for PCOS treatment."}], "state": "complete"}], "gaps": []}, "experiment": {"state": "complete", "objective": "FABP5 promotes active fatty acid synthesis and excessive proliferation of GCs by activating PI3K-AKT signaling.", "steps": [{"id": "read_published_estimate", "order": 1, "name": "Read the published estimate from the source", "kind": "other", "state": "complete", "blocked_on": null, "description": "The claim, method and evidence span published with the source article.", "duration_hours": null, "parameters": {}, "inputs": ["source:pmid:38373971"], "outputs": ["the published estimate and its evidence"], "instruments": [], "reagents": []}, {"id": "obtain_source_data", "order": 2, "name": "Obtain the source data from the named repository", "kind": "data-preparation", "state": "complete", "blocked_on": null, "description": "The GEO series accession resolves and its sample accessions are listed. This lane did not download the dataset or read its licence.", "duration_hours": null, "parameters": {}, "inputs": ["data:geo:GSE138518"], "outputs": ["the source data with its repository provenance"], "instruments": [], "reagents": []}, {"id": "run_analysis", "order": 3, "name": "Run the published analysis", "kind": "analysis", "state": "complete", "blocked_on": null, "description": "Apply the paper's statistical method to the resolved series and compare the result with the published target.", "duration_hours": null, "parameters": {}, "inputs": ["data:geo:GSE138518"], "outputs": ["the replicated result and its comparison"], "instruments": [], "reagents": []}], "materials": [], "instruments": [], "reagents": [], "conditions": {}, "gaps": []}, "data": {"state": "partial", "assets": [{"id": "source:pmid:38373971", "role": "manuscript", "format": "xml", "media_type": "application/xml", "uri": "https://doi.org/10.1186/s13048-024-01368-6", "sha256": "sha256:34f098a9b5a228aafd0edcc30f8cbe7215f896d6da44b8269de1893c1619eeae", "bytes": 42630, "access": "open", "state": "resolved", "reader": null, "reader_status": "reader_required", "identifier": "10.1186/s13048-024-01368-6", "version": null, "note": "Full article fetched from PMC; the checksum covers the rendered section body, not the original XML bytes.", "structure": {"pmcid": "PMC10875862", "source": "europe_pmc_fulltext", "coverage": "whole_body_without_references", "text_hash_scope": "rendered_section_body"}}, {"id": "data:geo:GSE138518", "role": "raw", "format": "geo-series", "media_type": "application/vnd.ncbi.geo-series+json", "uri": "https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE138518", "sha256": null, "bytes": null, "access": "open", "state": "resolved", "reader": null, "reader_status": "reader_required", "identifier": "GSE138518", "version": null, "note": "We downloaded the gene expression profiles of GSE138518 from the GEO database (https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE138518) [24]. 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Cell prolife"], "order_basis": "paper_text_order:724", "id": "assay:1"}, {"role": "data_generation", "definition_id": "western_blot", "definition_version": "99e1195c7d6f", "definition_digest": null, "required_operations": [], "support_state": "partial", "source_hashes": {"assay_lexicon": "99e1195c7d6f"}, "confidence": 0.99, "evidence": ["by quantitative real-time PCR (qRT‒PCR) and western blotting. Cell proliferation was evaluated with a cel", "ed with a cell counting kit-8 (CCK-8) assay. Western blotting was used to assess the expression of the pro", "the ovaries of mice with PCOS determined by Western blot analysis (n = 4). F Immunohistochemical plot", "with PCOS measured by qRT‒PCR (n = 6). D, E Immunoblot plot (D) and bar plot of the statistical ana"], "order_basis": "paper_text_order:753", "id": "assay:2"}, {"role": "data_generation", "definition_id": "apoptosis_assay", "definition_version": "99e1195c7d6f", "definition_digest": null, "required_operations": [], "support_state": "partial", "source_hashes": {"assay_lexicon": "99e1195c7d6f"}, "confidence": 0.93, "evidence": ["on was evaluated with a cell counting kit-8 (CCK-8) assay. Western blotting was used to assess"], "order_basis": "paper_text_order:831", "id": "assay:3"}, {"role": "data_generation", "definition_id": "ihc", "definition_version": "99e1195c7d6f", "definition_digest": null, "required_operations": [], "support_state": "partial", "source_hashes": {"assay_lexicon": "99e1195c7d6f"}, "confidence": 0.99, "evidence": ["ession of the proliferation marker PCNA, and immunofluorescence microscopy was used to detect Ki67 expressio", "nofluorescence microscopy was used to detect Ki67 expression. Moreover, lipid droplet formatio", "termined by Western blot analysis (n = 4). F Immunohistochemical plot of FABP5 expression and localization in", "ividuals, as measured by qRT‒PCR (n = 12). B Immunofluorescence staining of FABP5 in human primary ovarian G"], "order_basis": "paper_text_order:934", "id": "assay:4"}, {"role": "data_generation", "definition_id": "transfection", "definition_version": "99e1195c7d6f", "definition_digest": null, "required_operations": [], "support_state": "partial", "source_hashes": {"assay_lexicon": "99e1195c7d6f"}, "confidence": 0.99, "evidence": ["ined from PCOS patients and PCOS mice. FABP5 knockdown suppressed lipid droplet formation and proli", "feration. Moreover, we determined that FABP5 knockdown inhibited PI3K-AKT signaling by suppressing", "and lipid droplet formation caused by FABP5 knockdown. CONCLUSIONS: FABP5 promotes active fatty ac", "t 37 °C with 5% CO2. Forty-eight hours after transfection with the myc-FABP5 plasmid or FABP5 siRNA, K"], "order_basis": "paper_text_order:1256", "id": "assay:5"}, {"role": "data_generation", "definition_id": "cell_culture", "definition_version": "99e1195c7d6f", "definition_digest": null, "required_operations": [], "support_state": "partial", "source_hashes": {"assay_lexicon": "99e1195c7d6f"}, "confidence": 0.85, "evidence": ["re used in cell culture experiments. The KGN cell line was grown in DMEM/F12 medium (Corning, New York, USA)"], "order_basis": "paper_text_order:4061", "id": "assay:6"}, {"role": "data_generation", "definition_id": "animal_model", "definition_version": "99e1195c7d6f", "definition_digest": null, "required_operations": [], "support_state": "partial", "source_hashes": {"assay_lexicon": "99e1195c7d6f"}, "confidence": 0.69, "evidence": ["s and oocytes at all follicle levels in PCOS mouse ovaries (Fig. 2F).Fig. 2Aberrantly increased"], "order_basis": "paper_text_order:5915", "id": "assay:7"}]}