Identification and analysis of KLF13 variants in patients with congenital heart disease

Abstract

Background: The protein Kruppel-like factor 13 (KLF13) is a member of the KLF family that has been identified as a novel cardiac transcription factor which is involved in heart development. However, the relationship between KLF13 variants and CHDs in humans remains largely unknown. The present study aimed to screen the KLF13 variants in CHDs patients and genetically analyze the function of these variants. Methods: KLF13 variants were sequenced in a cohort of 309 CHD patients and population-matched healthy controls (n = 200) using targeted sequencing. To investigate the effect of variants on the functional ability of the KLF13 protein, the expressions and subcellular localization of protein, as well as the transcriptional activities of downstream genes and physically interacted with other transcription factor were assessed. Results: Two novel heterozygous variants, c.487C>T (P163S) and c.467G>A (S156N), were identified in two out of 309 CHDs patients with Tricuspid-valve atresia and transposition of the great arteries, respectively. No variants were found among healthy controls. The variant c.467G>A (S156N) increased protein expression and enhanced functionality compared with that of wild-type, without affecting the subcellular localization. The other variant, c.487C>T (P163S), did not show any abnormalities in protein expression and subcellular localization, however it eliminated the transcriptional activities of downstream target genes and physically interacted with TBX5, another cardiac transcription factor. Conclusion: Our results show that the S156N and P163S variants contributed to CHD etiology. Additionally, our findings suggest that KLF13 may be a potential gene contributing to congenital heart disease.

A novel KLF13 mutation underlying congenital patent ductus arteriosus and ventricular septal defect, as well as bicuspid aortic valve

“…As one member of the KLF family, the KLF13 protein harbors four critical structural domains encompassing a transactivation domain, which functions to transactivate downstream target genes, a transcriptional inhibition domain, which serves to transcriptionally inhibit downstream target genes, a nuclear localization signals responsible for nuclear localization, and three zinc-fingers required for binding to target gene promoters and interaction with other transcriptionally cooperative partners (67,87). Previous investigations have substantiated the ample expression of KLF13 in the hearts of both humans and vertebrates during embryonic development, and the pivotal effect of KLF13 on cardiovascular morphogenesis (66,67,86,88). Recent experimental studies have corroborated that KLF13 transactivates the expression of several downstream genes, encompassing NPPA, NPPB, VEGFA and ACTC1, separately or synergistically with TBX5, GATA4 and GATA6 (86,88).…”

“…Notably, KLF13 variations have been reported to cause distinct types of congenital cardiovascular deformities in humans, including TGA, TVA, DORV, VSD and ASD (66,67). In the present study, the affected family members who carried an identified KLF13 mutation manifested PDA, BAV and VSD, therefore expanding the phenotypic spectrum ascribed to mutant KLF13 and highlighting the genetic heterogeneity of CHD.…”

“…Notably, mutations in the Kruppel-like factor 13 (KLF13) gene, which codes for a Kruppel-like transcription factor crucial for proper cardiovascular morphogenesis, have recently been discovered to cause distinct types of CHD (66,67). Li et al (66) performed targeted sequencing analyses of the entire coding region of KLF13 in a cohort of 309 index patients suffering from CHD, and found two heterozygous KLF13 variants in 2 out of 309 CHD patients, including NM_015995.3: c.467G>A; p.(Ser156Asn) in one patient affected with TGA and NM_015995.3: c.487C>T; p.(Pro163Ser) in another patient with TVA, VSD and ASD. These two missense mutations were absent from 200 population-matched healthy controls.…”

“…Biological assays elucidated that Ser156Asn-mutant KLF13 had enhanced transcriptional activation on the downstream target gene brain natriuretic peptide, alone or in synergy with TBX5, and a significantly enhanced ability to bind physically to TBX5, whereas the Pro163Ser variant showed a loss-of-function effect (66). Wang et al (67) performed whole-exome sequencing analyses in a family with a high incidence of CHD (DORV and VSD), and identified a new KLF13 variant, NM_015995.3: c.370G>T; p.(Glu124*).…”

The Involvement of Krüppel-like Factors in Cardiovascular Diseases

“…In contrast, S156N had a significantly increased ability to interact with TBX5. Although, authors suggest that the overexpression of KLF-13 associated to S156N might be accompanied by higher protein instability, resulting in a loss-of function phenotype [85] Lavallée et al, have previously described similar results, identifying Klf-13 as a modifier of Gata4, a key transcription factor for the cardiac natriuretic peptide genes Nppa and Nppb. In this study, Klf-13 Knockdown resulted in atrial septal defects, hypotrabeculation and hypoplastic myocardium in Xenopus embryos [31].…”