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Updated: Mar 19, 2026
Detecting Migration and Infiltration of Neutrophils in Mice
Published on: February 6, 2020
Reduction of GPSM3 expression akin to the arthritis-protective SNP rs204989 differentially affects migration in a
B J Gall1, A B Schroer1, J D Gross1
1Department of Physiology and Pharmacology, West Virginia University School of Medicine, Morgantown, WV, USA.
Abstract:
G Protein Signaling Modulator-3 (GPSM3) is a leukocyte-specific regulator of G protein-coupled receptors (GPCRs), which binds inactivated Gαi·GDP subunits and precludes their reassociation with Gβγ subunits. GPSM3 deficiency protects mice from inflammatory arthritis and, in humans, GPSM3 single-nucleotide polymorphisms (SNPs) are inversely associated with the risk of rheumatoid arthritis development; recently, these polymorphisms were linked to one particular SNP (rs204989) that decreases GPSM3 transcript abundance. However, the precise role of GPSM3 in leukocyte biology is unknown. Here, we show that GPSM3 is induced in the human promyelocytic leukemia NB4 cell line following retinoic acid treatment, which differentiates this cell line into a model of neutrophil physiology (NB4*). Reducing GPSM3 expression in NB4* cells, akin to the effect ascribed to the rs204989 C>T transition, disrupts cellular migration toward leukotriene B4 (LTB4) and (to a lesser extent) interleukin-8 (a.k.a. IL-8 or CXCL8), but not migration toward formylated peptides (fMLP). As the chemoattractants LTB4 and CXCL8 are involved in recruitment of neutrophils to the arthritic joint, our results suggest that the arthritis-protective GPSM3 SNP rs204989 may act to decrease neutrophil chemoattractant responsiveness.
Insights
G Protein Signaling Modulator-3 (GPSM3) regulates leukocyte function. Reduced GPSM3 impairs neutrophil migration to inflammatory signals, suggesting a mechanism for how a GPSM3 gene variant protects against rheumatoid arthritis.
Area of Science:
- Immunology
- Molecular Biology
- Genetics
Background:
- G Protein Signaling Modulator-3 (GPSM3) is a leukocyte-specific regulator of G protein-coupled receptors (GPCRs).
- GPSM3 deficiency confers protection against inflammatory arthritis in mice.
- Human GPSM3 single-nucleotide polymorphisms (SNPs) are linked to rheumatoid arthritis risk, with one SNP (rs204989) decreasing GPSM3 transcript levels.
Purpose of the Study:
- To investigate the precise role of GPSM3 in leukocyte biology.
- To understand the functional consequences of reduced GPSM3 expression in neutrophils.
- To elucidate the potential mechanism by which the arthritis-protective GPSM3 SNP rs204989 influences rheumatoid arthritis risk.
Main Methods:
- GPSM3 expression was induced in a human promyelocytic leukemia NB4 cell line differentiated into a neutrophil model (NB4*).
- GPSM3 expression was reduced in NB4* cells, mimicking the rs204989 SNP effect.
- Neutrophil migration assays were performed using various chemoattractants, including leukotriene B4 (LTB4), interleukin-8 (CXCL8), and formylated peptides (fMLP).
Main Results:
- Reduced GPSM3 expression in NB4* cells significantly disrupted migration toward LTB4.
- Migration toward CXCL8 was also impaired, though to a lesser extent.
- Neutrophil migration toward fMLP was unaffected by GPSM3 reduction.
Conclusions:
- GPSM3 plays a critical role in regulating neutrophil chemotaxis toward specific inflammatory chemoattractants like LTB4 and CXCL8.
- The arthritis-protective GPSM3 SNP rs204989 may exert its effect by diminishing neutrophil responsiveness to these chemoattractants.
- These findings provide a molecular link between GPSM3 function, neutrophil behavior, and rheumatoid arthritis pathogenesis.
