IBD is a multifactorial disease that affected by a combination of environmental and genetic factors; the definite IBD etiology is still unrecognized (1).
This study carried out to reveal if there is an association between the SNP of the MYH9 gene and IBD. The study conducted on 150 subjects including 70 healthy controls, and 80 cases with IBD.
In this study, age and gender were not significantly different between cases and controls (p > 0.05). However, there was a statistically significant difference between cases and controls regarding BMI (p < 0.001). BMI was significantly higher in the IBD group compared to controls.
The continuous blood loss in addition to tenesmus, diarrhea, and other associated symptoms of IBD are responsible for decrease body weight as compared to the controls.
However, based upon the disease severity this change in the BMI could be insignificant. As reported by Hanafy et al. (2018) who reported that the mean values of the body mass index for the IBD and controls (11).
These current results were comparable to El-Hodhod et al. (2013) who reported that hemoglobin concentration was significantly lower in IBD patients during flare compared to controls (12)
In this study, regarding the distribution of rs3753462 of MYH9 in the IBD and control group, The CT and TT genotypes were significantly higher prevalence in the IBD group; T allele has 3.79-fold increase risk of IBD. In addition, on analyzing rs4821480 of MYH9, It was evident that the GG genotype had a significantly higher prevalence in IBD cases; G allele has 5.93-fold increase risk of IBD. Moreover, the GG genotype had significantly lower hemoglobin levels and higher BMI compared to the other two types. To the best of our knowledge, the polymorphisms in the MYH9 gene concerning IBD not tested before.
Many studies utilized genetic and pharmacologic inhibition of the heavy chains NM II to evaluate their importance in the monolayers model of the intestinal mucosa. These studies concluded that first, the motor activity of NM II is critical for the standard barrier properties preservation of these layers. Second, NM II has a significant responsibility in regulating the junctional remodeling by motivating 2 phases against each other: junctional assembly and reassembly. Third, the heavy chain of NM IIA works as a vital AJ/TJ functions regulator (13–15).
In several previous studies, the expression of MYH9 proved to be as an indicator to observe the progression and prognosis of gastrointestinal tract (16–21).
Another study found that MYH9 down-regulated many small interfering RNAs (siRNAs) in pancreatic cancer patients, and the down-regulation of tumor suppressor genes led to the occurrence of tumors (22).
A modern study on mice evaluating the specific NM IIA knockout in the epithelium of the intestine documented that the NM IIA loss was reasonable to increase the GIT barrier permeability and to stimulate low-grade inflammation in the intestine and elevates the sensitivity of the animal to colitis, which lead to severe erosion of the epithelium and more barrier breakdown exacerbation. (23).
The interactions of heavy chain with proteins, which bind to myosin, as well as specific heavy chain of NM IIA phosphorylation may have a relation with abnormal cytoskeleton organization in the intestinal epithelium lead to inflammation development in the intestine (24).
Outside the GIT, the polymorphisms of the (MYH9) gene have been claimed in dissimilar kidney diseases, as well as in diabetic nephropathy (25).
Several studies imply that MYH9/NMHC-IIA plays an important role in the invasive behavior of cancer cells. For instance, the EGF-dependent heavy chain phosphorylation of the myosin-IIA has a clear responsibility in mediating chemotaxis and motility (26). Myosin IIA seems to be the main mts1target (27), the metastasis- 1, and co-localizes with mts1 to the migrating tumor cells leading edge (28); mts1 affects both the myosin IIA phosphorylation and its assembly behavior (29, 30). A modern study associates MYH9 as an SRF target, that plays a role in cancer cell invasion and metastasis (31).
Further studies are required to explain the mechanism regulate functions of NM IIA in the epithelium of the intestine in the state of health and inflammation of GIT.