Vpliv diferenciacije skeletnomišičnih celic na izražanje receptorjev za citokine iz družine IL-6

Brdnik, Nuša (author), Pirkmajer, Sergej (mentor)

Ena izmed ključnih funkcij skeletnih mišic je njihova sekrecijska aktivnost. Skeletne mišice proizvajajo in izločajo citokine, ki jih imenujemo miokini. Miokini se sproščajo pod vplivom krčenja in delujejo avtokrino, parakrino ali endokrino. Prvi identificiran in najbolje raziskan miokin je interlevkin-6 (IL-6). Družino citokinov IL-6 definira skupna signalizacija preko na membrano vezanega receptorja glikoproteina 130. Citokini IL-6 imajo pomembno vlogo v avtokrini oziroma parakrini regulaciji metabolizma v skeletnih mišicah kot tudi v endokrini regulaciji raznovrstnih bioloških procesov v ostalih tkivih in organih preko aktivacije svojih receptorjev. Igrajo tudi ključno vlogo v patofiziologiji raznih metabolnih, jetrnih in gastrointestinalnih motenj, zaradi česar so postali zanimive farmacevtske tarče in središče pozornosti nedavnih raziskav. Medtem ko so sistemski učinki citokinov IL-6 dobro poznani, so njihovi mehanizmi delovanja in proizvodnja v skeletnih mišicah slabše raziskani. Poznavanje le-teh je ključno za nadaljnji razvoj zdravljenja različnih patofizioloških stanj. Vsi citokini IL-6, z izjemo IL-31, signalizirajo preko vsaj ene receptorske podenote gp130 in aktivirajo enake znotrajcelične signalne poti. Receptorji gp130 delujejo kot homodimer ali heterodimer, sestavljen iz ene gp130 β-receptorske podenote v kombinaciji z enim izmed ostalih treh β-receptorjev. Še zmeraj ne vemo, katere signalne poti se aktivirajo med diferenciacijo skeletnomišičnih celic, zato je bil namen tega dela preučiti izražanje izbranih receptorjev družine IL-6 na različnih stopnjah diferenciacije skeletnomišičnih celic. Kot eksperimentalni model smo uporabili kulture primarnih človeških skeletnomišičnih celic. Celice smo diferencirali v mišične cevčice sedem dni in nato analizirali izražanje tarčnih genov s kvantitativno verižno reakcijo s polimerazo v treh različnih stopnjah diferenciacije. Pokazali smo, da se izbrani receptorji za citokine iz družine IL-6; gp130, OSMR, LIFR, CNTFR in IL27RA izražajo med diferenciacijo skeletnomišičnih celic v kulturi in da raven njihovega izražanja ni odvisna od stopnje diferenciacije.

• Language: Slovenian
• Keywords: skeletna mišica, citokini, IL-6, diferenciacija
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FKKT - Faculty of Chemistry and Chemical Technology
• Year: 2023
• PID: 20.500.12556/RUL-149552
• COBISS.SI-ID: 164450051
• Publication date in RUL: 07.09.2023

Secondary language

• Language: English
• Title: Effect of differentiation of skeletal muscle cells on expression of receptors for the IL-6 family cytokines

Abstract

One of key functions of skeletal muscle is its secretory activity. Skeletal muscle produces and releases cytokines, which have been named myokines. Myokines are released in response to muscle contractions and exert autocrine, paracrine or endocrine effects. The first identified and most researched myokine is interleukin-6 (IL-6). The IL-6 family of cytokines is defined by its common signaling through the membrane bound receptor glycoprotein 130. IL-6 cytokines have an important role in autocrine and/or paracrine regulation of metabolism in skeletal muscle as well as in in regulation of various biological processes in other tissues and organs through their receptors. They are also implicated in the pathophysiology of various metabolic, liver and gastrointestinal disorders, which makes them interesting pharmaceutical targets and thus a focus of attention in recent research. The systemic effects of IL-6 cytokines are well known, but their mechanisms of action and their production in skeletal muscle are still not fully elucidated, which will be crucial for the development of treatments of various pathophysiological states. All IL-6 cytokines, except for IL-31, signal through at least one gp130 β-receptor subunit and induce common intracellular signaling pathways. Gp130 receptors function either as a homodimer or a heterodimer, comprised of one gp130 beta-receptor subunit in combination with one of the other three β-receptors. It is still not very well known which signaling pathways are activated during skeletal muscle cell differentiation. To shed further light on this topic, we aimed to determine the expression pattern of selected receptors of IL-6 family cytokines at different stages of differentiation. For the experimental model we used cultured primary human skeletal muscle cells. Cells were differentiated into myotubes for seven days and expression of target genes was analyzed using quantitative real-time PCR at three stages of differentiation. We demonstrated that the expression of selected receptors for the IL-6 family cytokines; gp130, OSMR, LIFR, CNTFR and IL27RA was constant during differentiation of cultured skeletal muscle cells.

• Keywords: skeletal muscle, cytokines, IL 6, differentiation