Special attention was given to integrin subunit alpha 7 ( ITGA7
), N-myc downstream-regulated gene 2 ( NDRG2 ), and paired-like homeodomain transcription factor 2 ( PITX2 ) due to their roles in tumorigenesis.
Integrins are heterodimeric transmembrane glycoproteins consisting of an a and [sz] chain and play a role in mediating cell-cell and cell-matrix adhesion. Integrin a7[sz]1 is a major laminin a2 receptor in skeletal myotubes and mature myofibers. The a7 subunit is encoded by ITGA7 gene, expressed mainly in skeletal and cardiac muscle.
So far, this subtype has only described in three patients with normal laminin a2 but absent integrin a7 caused by mutations in ITGA7 gene. Phenotype of the subtype is variable.
As for the four subtypes of integrin, it was found that ITGA7 was the one that has been significantly promoted by Npnt (3.31 [+ or -] 0.10-fold); on the contrary, FCOL1 repressed its expression by 53% compared to noncoated control.
The results highlighted that Npnt triggered the upregulation of ITGA1 (1.31 [+ or -] 0.04-fold), ITGA4 (1.40 [+ or -] 0.05-fold), ITGA7 (1.33 [+ or -] 0.07-fold), and ITGB1 (1.87 [+ or -] 0.09-fold).
In addition, ITGA7 was found to be remarkably increased by Npnt as much as threefold more than the noncoated control, denoting that the ITGA7 may be required in the interaction between Npnt and hDPSCs at the late stage of osteoblastic differentiation.
Moreover, Npnt acts as a bioactive signal to initiate the upregulation of ITGA1, ITGA4, ITGA7, and ITGB1 as early as day five.
The quantitative mRNA expression of integrin [alpha]1 (ITGA1, (a)), [alpha]2 (ITGA2, (b)), [alpha]3 (ITGA3, (c)), [alpha]4 (ITGA4, (d)), [alpha]5 (ITGA5, (e)), [alpha]6 (ITGA6, (f)), [alpha]7 (ITGA7, (g)), [alpha]8 (ITGA8, (h)), [beta]1 (ITGB1, (i)), and [beta]3 (ITGB3, (j)) was determined by real-time RT-PCR.
Genetic screening of genes causing hereditary skeletal and cardiomyopathies was performed using targeted next-generation sequencing, and the screened gene panel included SGCD , TCAP , TRIM32 , TTN , FKTN , MYOT , LMNA , CAV3 , EMD , FHL1 , LAMA2 , ITGA7
, SEPN1 , ACTA1 , DES , CRYAB , LDB3 , BAG3 , STA , DMD , MYH7 , and LAMP2 .