Investigating the diversity of extracellular vesicle microRNA in response to exercise-induced muscle micro-damage: comparison of targeted plasma microRNA to targeted and in-depth analysis of extracellular vesicle microRNA

Date
2020-12
Journal Title
Journal ISSN
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Publisher
Stellenbosch : Stellenbosch University
Abstract
ENGLISH ABSTRACT: Background: Skeletal muscle (SkM) damage occurs routinely in sport and is present in acquired and inherited myopathies. Damage is confirmed by invasive muscle biopsy. Molecular events that occur during SkM injury and repair, including localized immune cell involvement, may be reflected in circulation. A detailed understanding is essential to the development of diagnosis and intervention strategies. Extracellular vesicles (EVs) are nanoscale (30 to 1000 nm) mediators of intercellular communication. EVs are released in abundance by all cell types, contain cargo including microRNA, and are stable in circulation. Circulating EV profiles adapt to differing physiological and pathological states. EVs may therefore serve as non-invasive biomarkers of SkM injury and regenerative processes. Aims: To determine the biomarker potential of microRNAs in plasma, large EVs and small EVs in regard to skeletal muscle damage induced by unaccustomed eccentrically biased exercise. Methods: Two consecutive bouts of muscle-damaging exercise (plyometric jumping and downhill running) were performed by 9 healthy male volunteers. Blood samples were taken at baseline, 2 and 24 hr post-exercise. Serum creatine kinase (CK) and perceived muscle pain (PMP) served as indirect markers of muscle damage. Canonical myomiRs, SkM- important miRs and immune-important miRs were analysed in 3 avenues of biomarker: plasma, large EVs and small EVs. Large EVs were isolated using a 10 000 G centrifugation step, whilst the subsequent supernatant was used for plasma analysis and qEV size exclusion isolation of small EVs. Small and large EV-enriched isolates were visualized using STEM, and size and numbers were quantified using NTA. Based on NTA results the highest particle fractions (7- 10) from qEV columns were pooled for RNA analysis. qPCR analysis of plasma, large EV and small EV miRs was done with normalization to an exogenous control. Small RNA sequencing was done on 3 randomly selected participants’ small EV samples from baseline and 24 hr. Results: PMP and CK increased post-exercise. Small EVs were confirmed using gel electrophoresis, NTA and STEM. Large EVs were confirmed using NTA and STEM. Both small and large EVs were visualised using STEM. No change in small or large EVs size or number was seen post-exercise. Plasma miR-1, 133a and 206 increased in abundance at 2 hr, with miR-1 and 206 returning to BL levels at 24 hr. Conversely, plasma miR-208b & 499 also increased at 2 hr, but showed a trend toward a sustained increase at 24 hr. miR-31, a SkM-important miR, decreased in small EVs at 24 hr when compared to BL and 2 hr. No change in immune-important miRs was found in any biomarker source. Lastly, small RNA sequencing revealed an increase in 18 miRs in small EV at 24 hr post-exercise, with a concomitant decrease in 10 miRs. Conclusion: Both small EV and plasma miRs changed in response to muscle-damaging exercise. Each exhibited distinct miR changes, and timing of changes as shown by qPCR. miR-31, for example, decreased only in small EVs post-exercise, whereas most myomiRs increased only in plasma. RNA sequencing revealed more small EV miR changes. However, these were not corroborated with qPCR.
AFRIKAANSE OPSOMMING: Agtergrond: Skeletale spier-(SkM)-beskadiging kom gereeld in sport voor en is teenwoordig in verworwe en oorerflike miopatie. Skade word bevestig deur indringende spierbiopsie. Molekulêre gebeure wat tydens SkM-besering en -herstel plaasvind, insluitend gelokaliseerde immuun sel betrokkenheid, mag in die sirkulasie weerspieël word. 'n Gedetailleerde begrip is noodsaaklik vir die ontwikkeling van diagnoserings- en intervensiestrategieë. Ekstrasellulêre vesikels (EVs) is nanoskaal-bemiddelaars (30 tot 1000 nm) van intersellulêre kommunikasie. EVs word in oorvloed vrygestel deur alle seltipes, bevat identifiseerbare vragte, insluitend mikroRNS, en is stabiel in sirkulasie. Sirkulerende EV-profiele pas by verskillende fisiologiese en patologiese toestande aan. EVs kan dus dien as nie-indringende biomerkers van SkM-beserings en regeneratiewe prosesse. Doelstellings: Om die biomerkpotensiaal van mikroRNS'e in plasma, groot EVs en klein EVs te bepaal ten opsigte van skade aan skeletspiere, wat veroorsaak word deur ongewone eksentriek-bevooroordeelde oefening. Metodes: Twee opeenvolgende instellings van spierbeskadigde oefening (pliometriese spring en afdraanddraf) is deur 9 gesonde manlike vrywilligers uitgevoer. Bloedmonsters was op basislyn, 2 en 24 uur na oefening geneem. Serum kreatien kinase (CK) en subjektief-waargenome spierpyn (PMP) het as indirekte merkers van spierskade gedien. Kanonieke “myomiRs”, SkM-belangrike “miRs” en immuunbelangrike “miRs” is geanaliseer in 3 weë van die biomerkerbron: plasma, groot EV's en klein EVs. Groot EVs is geïsoleer met behulp van 'n 10 000 G sentrifugeringsstap, terwyl die daaropvolgende supernatant gebruik was vir isolasie van klein EVs deur middel van qEV-grootte uitsluitende isolasie en plasma-analise. Klein en groot EV-verrykte isolate is gevisualiseer met behulp van STEM, en grootte en getalle is met behulp van NTA gekwantifiseer. Op grond van NTA-resultate is die hoogste deeltjiefraksies (7-10) uit qEV- kolomme saamgevoeg vir RNA-analise. kPKR-analise van plasma, groot EV en klein EV miRs is uitgevoer deur middel van normalisering tot 'n eksogene kontrole. Klein RNS volgorde ontleding is gedoen op 3 lukraak geselekteerde deelnemers se klein EV-monsters vanaf basislyn en 24 uur. Resultate: PMP en serum CK het verhoog na oefening. Klein EVs is bevestig met behulp van gelelektroforese, NTA en STEM. Groot EVs is met behulp van NTA en STEM bevestig. Beide klein en groot EVs is gevisualiseer met behulp van STEM. Geen verandering in klein of groot EV-grootte of aantal is as gevolg van die oefening gesien nie. Plasma miR-1, 133a en 206 het op 2 uur in oorvloed toegeneem, met miR-1 en 206 wat op 24 uur na BL-vlakke teruggekeer het. Aan die ander kant het plasma miR-208b & 499 ook op 2 uur gestyg, maar het op 24 uur 'n neiging tot volgehoue toename getoon. miR-31, 'n SkM-belangrike miR, het in klein EVs op 24 uur afgeneem in vergelyking met BL en 2 uur vlakke. Geen verandering in immuunbelangrike miRs is in enige biomerkbron gevind nie. Laastens het klein RNS volgorde ontleding 'n toename getoon in 18 miRs in klein EV op 24 uur na oefening, met 'n gepaardgaande afname in 10 miRs. Gevolgtrekking: Beide klein EV en plasma miRs het verander na afloop van spierbeskadigende oefeninge. Elkeen het unieke miR, asook tydstip veranderinge getoon, soos aangedui deur kPKR. Byvoorbeeld, miR-31 het slegs in klein EV afgeneem na oefening, terwyl meeste mio-miRs slegs in plasma vermeerder het. RNS volgorde ontleding het verdere veranderinge in klein EVs getoon. Hierdie veranderinge was egter nie met kPKR bevestig nie.
Description
Thesis (PhD)--Stellenbosch University, 2020.
Keywords
Skeletal muscle, Exosomes, MicroRNA -- Analysis, Extracellular space -- Physiological aspects, UCTD
Citation