IGSF3 mutation identified in patient with severe COPD alters cell function and motility

Area of Science:

• Genetics
• Pulmonology
• Cell Biology

Background:

• Cigarette smoking (CS) and genetic factors significantly influence chronic obstructive pulmonary disease (COPD) risk and severity.
• A specific chromosomal translocation, 46,XX,t(1;4)(p13.1;q34.3), was investigated for its potential link to severe COPD.
• This translocation disrupts the immunoglobulin superfamily member 3 (IGSF3) gene, leading to reduced gene expression.

Purpose of the Study:

• To investigate the association between a chromosomal translocation affecting the IGSF3 gene and the risk of severe COPD.
• To explore the functional consequences of IGSF3 deficiency on cellular processes relevant to lung injury and repair.
• To identify specific IGSF3 single nucleotide polymorphisms (SNPs) associated with COPD severity and exacerbations.

Main Methods:

• Analysis of a patient with a balanced reciprocal chromosomal translocation and severe COPD.
• Examination of the COPDGene cohort to identify IGSF3 SNPs associated with COPD severity.
• Functional studies using patient-derived lymphoblastoids and lung structural cells with IGSF3 deficiency or knockdown.

Main Results:

• The translocation breakpoint was found within the IGSF3 gene, causing decreased expression.
• Fourteen IGSF3 SNPs were identified, with rs1414272 and rs12066192 directly associated and rs6703791 inversely associated with COPD severity.
• IGSF3 deficiency led to altered gene expression, changes in sphingolipid metabolism (increased ceramide), impaired cell repair, and weakened barrier function in lung cells.

Conclusions:

• IGSF3 plays a crucial role in maintaining sphingolipid homeostasis and membrane receptor function, essential for cell mobility and lung injury repair.
• IGSF3 deficiency compromises cellular repair mechanisms and barrier integrity, potentially increasing susceptibility to cigarette smoking-induced lung injury in COPD patients.
• Genetic variations in IGSF3 may contribute to COPD severity and exacerbation risk.