Lipocalin 2

Overview

Lipocalin 2 (LCN2), also known as neutrophil gelatinase-associated lipocalin (NGAL), is a secreted lipocalin-family protein with important roles in inflammation, tissue injury responses, and metabolic regulation. It is widely studied as a biomarker of kidney injury, but it is also increasingly recognized as a biologically active mediator rather than only a passive marker. In disease settings, LCN2 is often induced by inflammatory stimuli and stress signals, including bacterial lipopolysaccharide, high glucose, and other injury-associated cues.

Beyond its established use in renal research, LCN2 has been implicated in metabolic dysfunction associated steatotic liver disease, Metabolic dysfunction associated steatohepatitis (MASH), muscle atrophy, and neuroinflammatory responses. Recent studies also connect LCN2 with pathways involving IL-6, iNOS, PPARα activation, oxidative stress, and renal tubular injury markers such as KIM-1. These findings support a broader view of LCN2 as a stress-responsive mediator linking inflammation, organ injury, and systemic metabolic disease.

Focus of Latest Publications

Recent publications have examined LCN2 in several disease contexts, most prominently asthma, kidney injury, metabolic disease, and neuroinflammation.

In asthma, one study identified a novel Fra2/LCN2 axis by which PM2.5 exposure aggravates disease pathogenesis. The authors reported that activation of Fos-related antigen 2 (Fra2) and Lipocalin 2 promotes ferroptosis in M2 macrophages, thereby contributing to PM2.5-exacerbated asthma. This places LCN2 within a pro-inflammatory, cell-death-associated pathway involving macrophage polarization and ferroptosis, and suggests that suppressing the Fra2/LCN2 axis may attenuate pollutant-driven airway inflammation.

In cancer-related cell biology, LCN2 was targeted by CRISPR/Cas9 genome editing in MDA-MB-231 cells using an optimized lipid nanoparticle delivery platform. Knockout of the LCN2 gene produced a strong reduction in mRNA expression and was associated with inhibited cell proliferation and migration. Although the publication focused on delivery technology, the reported phenotype supports a role for LCN2 in supporting malignant cell growth and motility in this breast cancer model.

LCN2 also appeared in a study of social disruption-induced behavioral changes, where ubiquinol reduced hippocampal inflammatory responses. The treatment suppressed the upregulation of inducible nitric oxide synthase (iNOS), LCN2, and interleukin-6 (IL-6), indicating that LCN2 is part of a neuroinflammatory signature responsive to antioxidant intervention and PPARα-linked modulation.

In kidney research, LCN2 was referenced as a comparator biomarker in an acute kidney injury (AKI) diagnostic study following kidney transplantation. The study developed a four-gene signature and reported favorable clinical utility for early AKI identification compared with established biomarkers such as neutrophil gelatinase-associated lipocalin. This underscores LCN2/NGAL’s continued role as a benchmark marker in renal injury assessment, even when newer molecular signatures are being evaluated.

A separate renal biomarker study involving diabetic nephropathy severity mentioned NGAL among renal tubular injury markers correlated with circulating fibrinogen-like protein 2. While LCN2 was not the primary focus there, its inclusion alongside KIM-1 and inflammatory mediators reflects its established position in kidney injury biology.

LCN2 was also highlighted in metabolic liver disease research. In murine MASH models, investigators identified LCN2, LGALS3, and osteopontin (OPN) as MASH-induced hepatokines. The study concluded that these hepatokines drive muscle atrophy, linking LCN2 to liver-to-muscle endocrine signaling in metabolic dysfunction associated steatotic liver disease and Metabolic dysfunction associated steatohepatitis. This expands LCN2’s relevance beyond inflammation and kidney injury to systemic metabolic crosstalk and skeletal muscle wasting.

In another study, galantamine treatment in lupus mice reduced renal injury markers, including urinary albumin, kidney injury molecule-1, and NGAL, and improved survival and blood pressure. Here, LCN2 served as part of the renal injury readout in a systemic autoimmune model, again reinforcing its utility as a marker of kidney damage in inflammatory disease.

LCN2 was also measured in a behavioral neuroscience study in which ubiquinol suppressed hippocampal iNOS, LCN2, and IL-6 after social disruption stress, suggesting that LCN2 may participate in central inflammatory responses associated with stress-related behavioral changes.

Overall, the recent literature presented here portrays LCN2 as a multifunctional protein involved in inflammatory amplification, ferroptosis-related macrophage dysfunction, tumor cell behavior, hepatokine signaling, and renal injury biomarker biology. Its repeated appearance alongside interleukin-6, oxidative stress, KEAP1/Nrf2-related pathways, macrophage activation, and ferroptosis highlights its broad integration into immune-metabolic disease networks.

Key Publications

NEWMay Targeting the Fra2/LCN2 axis attenuates PM2.5-aggravated asthma by suppressing M2 macrophage ferroptosis. (Redox biology, 2026, PMID 42214888): "This study identifies a novel pathway by which PM2.5 promotes asthma pathogenesis by activating the Fos-related antigen 2 (Fra2)/Lipocalin 2 (LCN2) axis, thereby inducing ferroptosis in M2 macrophages."
NEWJul An optimised lipid nanoparticle platform enables efficient CRISPR/Cas9 genome editing in hard-to-transfect cells. (Acta biomaterialia, 2026, PMID 42214710): "Knockout of the LCN2 gene in MDA-MB-231 cells resulted in a 90.8% reduction in mRNA expression, outperforming the 51.1% reduction achieved using CRISPRMAX Lipofectamine, and functional assays confirmed that LCN2 disruption significantly inhibited cell proliferation and migration."
NEWJun Ubiquinol ameliorates social disruption-induced behavioral changes via modulating inflammatory responses and PPARα activation. (Behavioural brain research, 2026, PMID 41962635): "Additionally, ubiquinol suppressed SD-induced upregulation of inducible nitric oxide synthase (iNOS), lipocalin 2, and interleukin-6 (IL-6) in the hippocampus."
Jun CDK5-p25 Peptide Inhibitor Samples an Intrinsically Disordered Ensemble in Solution. (The journal of physical chemistry. B, 2026, PMID 42284526): "The 24-residue peptide p5 (KEAFWDRCLSVINLMSSKMLQINA) selectively inhibits the pathological CDK5-p25 complex implicated in Alzheimer's disease and other neurodegenerative disorders, yet the structural basis for this selectivity remains poorly understood."
Jun A four-gene signature for diagnosis of acute kidney injury following kidney transplantation. (Renal failure, 2026, PMID 42315974): "Decision curve analyses indicated potential clinical utility for early AKI identification across a broad threshold-probability range, with favorable performance compared with several established biomarkers such as neutrophil gelatinase-associated lipocalin."
Jun Hepatokines lipocalin 2 and osteopontin drive muscle atrophy in MASH. (Molecular metabolism, 2026, PMID 42270040): "we identified three MASH-induced hepatokines, namely LCN2, LGALS3 and OPN."
May Serum fibrinogen-like protein 2 is associated with diabetic nephropathy severity and modulates high glucose-induced tubular dysfunction via Akt-FoxO1 signaling. (Renal failure, 2026, PMID 42161877): "Circulating FGL2 positively correlated with glycemic indices, insulin resistance, lipid parameters, renal tubular injury markers (NGAL, KIM-1), inflammatory cytokines (TNF-α, IL-6), and fibrotic mediators (TGF-β1, CTGF)."
May DNA-engineered immunosensing platform for ultrasensitive detection of clinical protein biomarkers. (Biosensors & bioelectronics, 2026, PMID 41655520): "As proof of concept, DEISP was employed to detect the kidney injury biomarker neutrophil gelatinase-associated lipocalin (NGAL), the pro-inflammatory cytokine interleukin-6 (IL-6), and the cardiac troponin I (cTnI) associated with myocardial infarction, demonstrating remarkable sensitivity with limits of detection (LODs) of 0.025 pg mL-1 for NGAL, 0.026 pg mL-1 for IL-6, and 2.35 pg mL-1 for cTnI."
May Cafestol ameliorates diabetic nephropathy via Keap1-Nrf2 axis activation: A novel renoprotective mechanism independent of glycemic control. (PloS one, 2026, PMID 42133719): "In the control rats, Cafestol (10 mg/kg) did not cause any significant changes to any of the measured parameters, including 24-hour urine volume, urinary albumin, creatinine, and renal injury parameters (KIM-1, NGAL, nephrin), suggesting that Cafestol has no adverse renal effect in normal physiology."
May Acetylcholinesterase inhibitor therapy mitigates hypertension in lupus mice. (Clinical science (London, England : 1979), 2026, PMID 42003680): "Long-term galantamine treatment improved survival; lowered blood pressure; reduced renal injury markers, including urinary albumin, kidney injury molecule-1, and neutrophil gelatinase-associated lipocalin; and decreased renal fibrosis in female mice with SLE."