CRISPR/Cas9 Unsettle PIP4K2A and α, β, and γ Globin Genes Expression

Phosphatidylinositol-phosphate kinases (PIPKins) belong to a family of lipid kinase enzymes that generate lipid messengers derivate from inositol, including the second messenger phosphatidylinositol-4,5-biphosphate [PI(4,5)P2], which participates in several cell regulation processes including gene expression. Previous studies developed in our laboratory suggested that the enzyme phosphatidylinositol-4-phosphate kinase-II-alpha (PIP4KIIα) may be related with the expression of the globin genes. Thus, the aim of this work was to evaluate the expression levels of the α, β and γ globin genes after disruption and overexpression of the PIP4KIIα gene (PIP4KIIA) in KU812 erythroleukemic cell line. The PIP4KIIα gene disruption was performed by using CRISPR/Cas9 and CRISPR/dCas9 techniques: KU812 cells were electro-transfected (Lonza 4D Nucleofector) with CRISPR/Cas9 lentiviral plasmid construct containing 3 gRNA targets to exon 8 of PIP4KIIA to knockout the gene; RNA samples from the pool of cells were collected and quantified by qPCR after 9 (t1) and 14 days (t2) of transfection. To overexpress PIP4K2A, CRISPR/dCas9 system (five lentiviral plasmids - 3 gRNAs targeting 214 nt upstream the transcriptional start site of PIP4K2A and 2 SAM accessorial factors) was transfected (Lipofectamine 3000) and RNA quantified by qPCR 24 (h1), 48 (h2) and 72 (h3) hours after the procedure. β-ACTIN and GAPDH genes were used as endogenous controls for qPCR. Our results with transfected cells without selection revealed, as expected, a reduction of PIP4KIIA compared to the control (no transfected cells - t1 and t2). The α globin genes presented a variation of 42% (increase in t1) and a 60% reduction in t2 (RQ = 1.42; RQ = 0.40, respectively), while β globin genes presented a 123% increase in t1 and remained similar to the control at t2 (RQ = 2.23; RQ = 1.01). The γ globin genes presented variation of 18% and 59% reduction in t1 and t2, respectively (RQ = 0.82; RQ = 0.41). The overexpression results suggested that PIP4KIIA leads to a higher γ globin expression in h2 and h3 (RQ = 3.26; RQ = 2.01) as well as a lower β globin expression in h1, h2 and h3 (RQ = 0.54; RQ = 0.002; RQ = 0.18), while a globin remained similar to the control at all analysed times (RQ variation of 1.26; 0.82 and 1.25, respectively). These results, although preliminary, suggest a possible relationship between PIP4KIIα and the regulation of expression of the globin genes. Financial Support: Fapesp, CNPq, CAPES, Faepex-Unicamp.