Yeseung Jeong Essay

Genetic Underpinnings of Irritable Bowel Syndrome: Personal and Familial Journey 20221356 Yeseung Jeong

My Interest
I’m in interested in mucosal immune system, and the drug delivery system. Mucosal immunology is the study of immune system responses that occur at mucosal membranes of the intestines, the urogenital tract, and the respiratory system. In healthy states, the mucosal immune system protects the organism against infectious pathogens and maintains a tolerance towards non-harmful commensal microbes and benign environmental substances[1]. Disruption of this balance between tolerance and deprivation of pathogens can lead to pathological conditions such as food allergies, irritable bowel syndrome, susceptibility to infections, and more.[2]
I especially interested in irritable bowel syndrome (IBS). IBS is a functional gastrointestinal disorder characterized by a group of symptoms that commonly include abdominal pain, abdominal bloating and changes in the consistency of bowel movements.[3] The reason why I have interest in this symptom is I am the patient. I usually got symptoms relating to the genitourinary system and bloating. My family, especially paternal line has same symptoms. So, I really wanted to search what genomic state makes ill our family.

Gene Relation
First, I searched that IBS is really related in gene. By the research “Non-colonic features of irritable bowel syndrome” (Whorwell, 1986), up to 33% of patients with IBS had a family history of IBS compared to 2% of the control.[4] Through this study, I found out that IBS is a syndrome with a family history. And I want to find that what gene is occurring IBS.
IBS encountered worldwide, the global prevalence and the symptom of IBS varies from different regions and ethnic groups.[5] By this research paper, In Korean, 5HTTLPR (S/S in short(S) or long(L) allele), α2A-adrenergic receptor (-1291C/G), GNB3 (T homozygote in 825C/T), CNR1 ((AAT)n > 10 homozygote), CCK-1 receptor (re1800795(-174C/G)), IL-10 (G allele carriers in -1082A/G; C allele carriers in -592A/C), and TNF-α (GA heterozygote in -308G/A) makes IBS. From now, Finding relationships between IBS and these specific factors. First, 5HTTLPR is a polymorphism of the gene (SLC6A4) that encodes the serotonin transporter, and this mutation affects serotonin transport, causing IBS symptoms. Serotonin is a neurotransmitter that regulates the motility and secretion of the intestine. Second is α2A-adrenergic receptor. This is a receptor that transmits the signal of norepinephrine, and when a mutation occurs, it can affect the function of the autonomic nervous system and cause IBS symptoms. CNR1 encodes cannabinoid receptors, and mutations can affect the neural and immune responses of the intestine, causing IBS. GNB3 encodes the beta-3 subunit of the G protein, where the mutation affects the cellular signaling pathway, causing IBS symptoms. CCK-1receptor encodes the cholecystokinin receptor (hormone that promotes digestion of fat or protein in the digestive system), and mutations can affect the action of cholecystokinin in the digestion process, causing IBS symptoms. IL-10 is an anti-inflammatory cytokine, but when a mutation occurs, it may cause problems in controlling the inflammatory response and cause IBS symptoms. Last one, TNF- α will be mentioned later.

Researches
In another research. The serotonin transporter (SERT) gene encoding the SERT protein is located on chromosome 17q11.1-9.12. An association was reported between a functional polymorphism in the SERT gene and diarrhoea-predominant IBS.[6] Individuals with a long allele genotype of the SERT gene have been shown to be vulnerable to developing IBS with constipation.
Another research that I found is named “Identifying and testing candidate genetic polymorphisms in the irritable bowel syndrome (IBS): association with TNFSF15 and TNFα” (Swan, 2013).[7] It explained two genes related to IBS. TNFSF15 gene that acts regulating inflammatory reaction appears with higher frequency in IBS patients. The other gene is TNFα. This gene encodes a tumor necrosis factor alpha. TNFα is a major cytokine that triggers the inflammatory response, and polymorphism of the TNFα gene in IBS patients is associated with the inflammatory response and worsening symptoms.

Conclusion
In conclusion, my interest is wholly related to Genomics. Analyzing genes make more comprehension about IBS. When I can do my own research, I would use result of analyzing IBS to my research. I want to get the goal of drug delivery of personal disease, especially IBS. IBS has many types. Someday I want to cure the whole symptoms of IBS. Genomics course is helpful for my searching and thinking ability.

 

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[1] Wikipedia. “Mucosal immunology”, https://en.wikipedia.org/wiki/Mucosal_immunology#cite_note-Zheng_2020-2

[2] Danping Zheng, Timur Liwinski, and Eran Elinav, "Interaction between Microbiota and Immunity in Health and Disease," Cell Research 30 (2020): 492-506, https://doi.org/10.1038/s41422-020-0332-7

[3] NIH. “Definition and Facts for Irritable Bowel Syndrome”, https://zrr.kr/gFfb

[4] P. J. Whorwell, M. McCallum, F. H. Creed, and C. T. Roberts, "Non-colonic Features of Irritable Bowel Syndrome," Gut 27, no. 1 (1986): 37-40, https://doi.org/10.1136/gut.27.1.37

[5] Qi-Yun Xiao et al., "Ethnic Differences in Genetic Polymorphism Associated with Irritable Bowel Syndrome," World Journal of Gastroenterology 26, no. 17 (2020): 2049-2063, https://doi.org/10.3748/wjg.v26.i17.2049

[6] Magdy El-Salhy, "Irritable Bowel Syndrome: Diagnosis and Pathogenesis," World Journal of Gastroenterology 18, no. 37 (2012): 5151-5163, https://doi.org/10.3748/wjg.v18.i37.5151

[7] Swan C, Duroudier NP, Campbell E, et al. “Identifying and testing candidate genetic polymorphisms in the irritable bowel syndrome (IBS): association with TNFSF15 and TNFα”, Gut 62, no.7 (2013): 985-994, https://gut.bmj.com/content/62/7/985