Overview
MIF-1, also known as Melanostatin or Pro-Leu-Gly-NH2, is a naturally occurring tripeptide made up of just three amino acids — proline, leucine, and glycinamide — that is found in the body and has also been synthesized for laboratory use. It belongs to the neuropeptide category and has drawn scientific interest for its role as a positive allosteric modulator of dopamine receptors, meaning it appears to influence how those receptors respond to signals rather than directly activating them. Researchers have also investigated its potential connections to the MIF cytokine family, which is associated with immune and inflammatory processes. With a relatively simple molecular structure and an endogenous origin, MIF-1 serves as a useful reference compound in studies exploring dopaminergic signaling and related biological pathways. Like all peptides listed on this site, MIF-1 is intended strictly for laboratory research purposes and is not approved for human use.
Research & Bioactivity
Researchers have studied MIF-1, also known as melanostatin, across several areas of biology, including neuroscience, immunology, inflammation, and parasitology. In the context of the central nervous system, studies have examined MIF-1's role as a positive allosteric modulator of dopamine D receptors, with in vitro and pharmacological research investigating how structural modifications to the peptide influence its activity at these receptor targets. Research has also explored MIF-1 in the context of inflammatory signaling, particularly its identity as a pro-inflammatory cytokine within the macrophage migration inhibitory factor family, with studies examining its potential as a biomarker in models of cardiac dysfunction. In the field of oncology and inflammation, researchers have investigated dual inhibition strategies targeting both MIF-1 and the related protein D-dopachrome tautomerase, designing and screening novel compounds in laboratory settings. Additionally, studies have examined the role of MIF-family proteins in host-parasite interactions, exploring how parasitic organisms may utilize MIF-related molecules to influence immune responses in animal infection models.
Published Research
Discovery of Furan-2-Carboxylic Acid Derivatives as Novel D-Dopachrome Tautomerase (D-DT) and Macrophage Migration Inhibitory Factor-1 (MIF-1) Dual Inhibitors.
Wu Z, Widjaja V, Skeens E, van der Velde JJH, Zahran M, et al. — 2026
D-dopachrome tautomerase (D-DT), also known as macrophage migration inhibitory factor-2, is a member of the MIF cytokine family and plays a key role in cancer and inflammation. Molecules that bind to the D-DT or MIF-1 tautomerase site could block their biological activity. However, relatively few D-DT inhibitors have been reported. In this study, we designed, synthesized, and screened a focused compound library. This led to the identification of , a furan-2-carboxylic acid derivative with IC values of 2.4 μM for D-DT and 9.8 μM for MIF-1. Subsequent SAR optimization yielded the more potent inhibitor , exhibiting IC values of 1.5 μM for D-DT and 1.0 μM for MIF-1. The specific interactions of with D-DT and MIF-1 were explored using H-N NMR endpoint titrations. also inhibited D-DT-induced ERK phosphorylation in A549 cells. Thus, and represent a new class of inhibitors that can be utilized as tools to investigate the biological functions of D-DT and MIF-1.
Discovery of first-in-class melanostatin-based ago-allosteric modulators of the dopamine D receptors.
Costa-Almeida HF, Correia XC, Silva-Reis SC, Pires-Lima BL, Costa VM, et al. — 2026
Melanostatin (MIF-1) is an endogenous tripeptide that acts as a positive allosteric modulator (PAM) of the dopamine D receptors (DR), making it a valuable pharmacological lead for the treatment of dopamine-related disorders of the central nervous system (CNS). In this study, a novel series of MIF-1 derivatives was synthesized and pharmacologically evaluated to investigate the influence of ring flexibility and stereochemistry on PAM activity. For this purpose, the alicyclic β-amino acids (1R,2S)-2-aminocyclopentane-1-carboxylic acid (cispentacin) and its unsaturated precursor, (1R,2S)-2-aminocyclopent-3-ene-1-carboxylic acid, were used as proline surrogates. The results obtained showed that cispentacin-based derivatives 8b and 9b displayed PAM activity at 10 pM, significantly reducing the EC of dopamine by 4.34- and 4.22-fold, respectively (8b: EC = 20.08 ± 3.95 nM; 9b: EC = 20.61 ± 4.60 nM). At 1 nM, 8b further decreased the EC of dopamine by 9.20-fold (EC = 9.47 ± 5.02 nM) and, at higher concentrations (10 and 100 μM), it activated the DR in the absence of dopamine, representing the first-in-class MIF-1-based ago-allosteric modulator of the DR. Cytotoxicity assays in human dopaminergic-differentiated SH-SY5Y cells showed that neither 8b nor 9b exhibited cytotoxic effects at 100 μM, as assessed by both the MTT reduction and neutral red uptake assays, supporting their favorable toxicological profiles. Overall, these findings demonstrate that a fine-tuned interplay between ring flexibility and stereochemistry is a key determinant in generating effective PAM of the DR, providing a framework for the future design of MIF-1-based modulators targeting Parkinson's disease and other dopamine-related CNS disorders.
Proline Homologation in Melanostatin Neuropeptide: Discovery of Potent Modulators of the Dopamine D Receptors.
Sampaio-Dias IE, Costa-Almeida HF, Correia XC, Silva-Reis SC, Costa VM, et al. — 2025
Melanostatin (MIF-1) is a naturally occurring neuropeptide acting as a positive allosteric modulator (PAM) of dopamine D receptors (DR), underscoring its potential for therapeutic use in central nervous system disorders associated with dopaminergic dysregulation, including depression, drug addiction, restless legs syndrome, tardive dyskinesia, and Parkinson's disease. In this work, a new series of MIF-1 analogs using l-pipecolic acid as an l-proline surrogate was synthesized and pharmacologically evaluated by functional assays at the DR. In this series, methyl l-pipecolyl-l-leucylglycinate () was found to exhibit superior performance compared to MIF-1 by promoting a 4.1- and 4.2-fold increase of dopamine potency at 0.01 and 1 nM, respectively. conformational studies demonstrate that preferentially adopts a γ-turn, corroborating that neither the C-terminal carboxamide nor the postulated type II β-turn conformation is required for PAM activity. Toxicological assays in human dopaminergic SH-SY5Y neuronal cells show that this compound exhibits no significant toxicity up to 100 μM in the MTT reduction and neutral red uptake assays.
Elevated Macrophage Migration Inhibitory Factor 1 Is Associated with Left and Right Ventricular Systolic Dysfunction in Heart Failure with Reduced Ejection Fraction.
Szabo TM, Vass M, Germán-Salló M, Frigy A, Nagy EE — 2025
: Low-grade systemic inflammation, characteristic of heart failure (HF), is a nonspecific inflammatory syndrome that affects the entire body. Macrophage migration inhibitory factor 1 (MIF-1) is a pro-inflammatory cytokine, a key mediator of the innate immune response, and may serve as a potential biomarker of monocyte homing and activation in HF with reduced and mildly reduced ejection fraction (HFrEF, HFmrEF). : We evaluated 70 hemodynamically stable patients with left ventricular EF (LVEF) < 50% by means of echocardiography and blood sampling. : We report significant correlations between MIF-1, LVEF (r = -0.33, = 0.005), LV global longitudinal strain (LVGLS, r = 0.41, = 0.0004), and tricuspid annular plane systolic excursion (TAPSE, r = -0.37, = 0.001). MIF-1 levels in HFrEF patients were relatively higher, but not significantly different from those observed in HFmrEF. MIF-1 showed significant associations with TAPSE to systolic pulmonary artery pressure ratio (TAPSE/sPAP, < 0.0001). Also, patients with TAPSE/sPAP < 0.40 mm/mmHg had significantly higher levels of MIF-1 ( = 0.009). Moreover, ischemic cardiomyopathy (ICM) was more frequent in patients with MIF-1 concentrations above 520 pg/mL (57.1% MIF-1 vs. 28.6% MIF-1, = 0.029). In terms of congestion, MIF-1 showed significant associations with the presence of peripheral edema ( = 0.007), but none was found with self-reported dyspnea ( = 0.307) and New York Heart Association (NYHA) class ( = 0.486). Also, no relationship was reported with N-terminal pro-B-type natriuretic peptide concentrations (NT-proBNP, r = 0.14, = 0.263). However, the six-minute walk distance was greater in individuals in the MIF-1 group when compared to those in the MIF-1 group (404.0 ± 127.4 vs. 324.8 ± 124.1 m, = 0.010). : Beyond identifying inflammatory biomarkers related to disease severity, linking MIF-1 to various pathophysiological mechanisms may highlight the active involvement of the monocyte-macrophage system in HF. This system holds notable significance in congestion-related conditions, acting as a major source of reactive oxygen species that perpetuate inflammation.
Analysis of the role of macrophage migration inhibitory factors in host-parasite interactions.
Karabowicz J, Długosz E, Bąska P, Pękacz M, Wysmołek ME, et al. — 2024
INTRODUCTION: is a zoonotic parasitic filarial nematode that infects carnivores and occasionally humans. Knowledge of the host-parasite molecular interactions enabling the parasite's avoidance of the host immune response in subcutaneous dirofilariasis remains limited. Parasitic orthologues of host macrophage migration inhibitory factor (MIF) are molecules potentially involved in this process. MATERIAL AND METHODS: Complementary DNA encoding two MIF orthologues (r-MIF-1 and r-MIF-2) was cloned into a pET-28a expression vector. The recombinant proteins were produced in and purified using affinity nickel chromatography. The reactivity of both recombinant proteins was analysed with infected dog and immunised mouse sera. RESULTS: Stronger antibody production was induced by rMIF-1 in mice, as evidenced by significantly higher levels of anti-r-MIF-1 total IgG, IgG2 and IgE antibodies than of anti-r-MIF-2 immunoglobulins. Additionally, a significantly different level of antibodies specific to both proteins was noted between the sera of infected dogs and those of uninfected dogs. CONCLUSION: This study is the first attempt to characterise MIF orthologues from the filarial parasite , which may affect the immune response during infection.