Vpliv genetske variabilnosti v presnovi folata na dolžino telomer v zdravi slovenski populaciji

Gomboc, Tjaša (author), Trebušak Podkrajšek, Katarina (mentor), Dolžan, Vita (co-mentor)

Telomere so kompleksne strukture na koncu linearnih kromosomov, ki ščitijo DNA pred skrajševanjem. Čeprav njihova vloga še ni popolnoma znana, imajo telomere pomemben vpliv na staranje. Z vsako delitvijo celice se telomere krajšajo, dokler ne postanejo tako kratke, da se celica več ne more deliti. Krajše kot so telomere, bolj smo dovzetni za bolezni, povezane s staranjem, med njimi rak, ateroskleroza, sladkorna bolezen in druge. Na krajšanje telomer negativno vplivajo tudi različni okoljski dejavniki, kot so kajenje, stres, neaktiven življenjski slog, strupene snovi iz okolja, debelost in podobno. V magistrski nalogi smo preučevali povezavo med dolžino telomer in prisotnimi polimorfizmi gena za metilentetrahidrofolat reduktazo (MTHFR). V ta namen smo v 183 vzorcih DNA zdravih preiskovancev dveh starostnih skupin (mlajše s povprečno starostjo 23 let (N = 91) in starejše s povprečno starostjo 57 let (N = 92)), ki so bili izolirani iz polne krvi, določili relativno dolžino telomer z monokromatsko multipleksno kvantitativno reakcijo s polimerazo. S kompetitivnim specifičnim alelnim PCR (angl. KASP PCR) pa smo genotipizirali polimorfizma rs1801131 in rs1801133 v genu, ki kodira metilentetrahidrofolat reduktazo (MTHFR). S statistično analizo smo nato preverili povezavo med relativno dolžino telomer in prisotnimi polimorfizmi. Preverili smo tudi vpliv spola in starosti preiskovancev na dolžino telomer. Noben izmed preučevanih kliničnih in genetskih dejavnikov ni bil statistično značilno povezan z dolžino telomer. Kljub temu, da sta povezavo med polimorfizmi gena MTHFR in dolžino telomer že raziskovali dve raziskavi, je naša raziskava prva, ki je preverjala dolžino telomer in polimorfizme gena MTHFR pri obeh spolih in v različnih starostnih skupinah. Naša raziskava je ena izmed mnogih, ki dokazuje, kako kompleksno je uravnavanje dolžine telomer in da imamo znanja o njih zaenkrat še premalo, da bi lahko prišli do klinično pomembnih zaključkov. Da bi lahko bolje ovrednotili vpliv polimorfizmov gena MTHFR na krajšanje telomer, bi bilo potrebno izvesti longitudinalne študije, ki bi vključevale večje število preiskovancev v določenem časovnem obdobju, o preiskovancih pa bi potrebovali tudi bistveno več podatkov kot zgolj spol in starost. Še posebej pomemben bi bil podatek o prehranskem vnosu folata, v raziskavo pa bi lahko vključili tudi več genov folatne poti.

• Language: Slovenian
• Keywords: relativna dolžina telomer, kvantitativna reakcija s polimerazo v realnem času, metilen-tetrahidrofolat reduktaza, polimorfizem, rs1801131, rs1801133
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2020
• PID: 20.500.12556/RUL-120745
• Publication date in RUL: 25.09.2020

Secondary language

• Language: English
• Title: The impact of genetic variability in folate metabolism on telomere length in healthy Slovenian population

Abstract

Telomeres are complex structures at the end of linear chromosomes that protect the DNA from shortening down in size. Altough their role is not yet fully understood, telomeres have a significant impact on aging. With each cell division, the telomeres shorten to the point, where they become so short, that the cells can no longer divide. The shorter the telomeres become, the more susceptible individual becomes to diseases associated with aging, as well as diseases such as atherosclerosis, diabetes and others. Telomere shortening is also adversely affected by various factors, such as smoking, stress, inactive lifestyles, toxic environmental substances, obesity etc. In this master’s thesis, we have studied the relationship between telomere length and polymorphisms in the methylenetetrahydrofolate reductase gene (MTHFR). For this purpose, the relative telomere length by monochromatic multiplex quantitative polymerase chain reaction was determined in 183 DNA samples from healthy subjects of two age groups (younger with average age of 23 years and older with average age of 57 years) isolated from whole blood. Competitive allele specific PCR (KASP PCR) was used to genotype the rs1801131 and rs1801133 in gene encoding methylenetetrahydrofolate reductase (MTHFR). With the statistical analysis, we then verified the relationship between the relative length of telomeres and the polymorphisms present. We also wanted to correlate telomere length regarding the gender and age of the subjects. We did not confirm an association between telomere length and selected factors, as the tests did not reach statistical significance. Although two previous studies had evaluated the relation of the telomere lenght and polymorphisms of the MTHFR gene, our study is the first to compare telomere length and MTHFR polymorphisms in both genders and in different age groups. Our study is one of many that demonstrate the complexity of the telomere length managment and the lack of knowledge in this field, making drawing clinically relevant conclusions difficult. In order to better evaluate if MTHFR polymorphisms affect telomere shortening, longitudinal studies involving a larger number of subjects over a period of time and more extensive clinical data would be required. Data on dietary folate intake would be particularly important. In addition, several folate pathway genes could be included in the study.

• Keywords: relative telomere length, quantitative polimerase chain reaction, methylenetetrahydrofolate reductase, polymorphism, rs1801131, rs1801133