title: Comprehensive selection of reference genes for expression studies in meniscus injury using quantitative real-time PCR.
abstract: The meniscus plays critical roles in the knee function. Meniscal tears can lead to knee osteoarthritis. Gene expression analysis may be a useful tool for understanding meniscus tears, and reverse-transcription quantitative polymerase chain reaction (RT-qPCR) has become an effective method for such studies. However, this technique requires the use of suitable reference genes for data normalization. We evaluated the suitability of six reference genes (18S, ACTB, B2M, GAPDH, HPRT1 and TBP) using meniscus samples of (1) 19 patients with isolated meniscal tears, (2) 20 patients with meniscal tears and combined anterior cruciate ligament injury (ACL), and (3) 11 controls without meniscal tears. The stability of the candidate reference genes was determined using the NormFinder, geNorm, BestKeeper DataAssist and RefFinder software packages and comparative ΔCt method. Overall, HPRT1 was the best single reference gene. However, GenEx software demonstrated that two or more reference genes should be used for gene expression normalization, which was confirmed when we evaluated TGFβR1 expression using several reference gene combinations. HPRT1+TBP was the most frequently identified pair from the analysis of samples of (1) meniscal tear samples of patients with a concomitant ACL tears, (2) all meniscal tears, and (3) all samples. HPRT1+GAPDH was the most frequently identified pair from the analysis of samples of isolated meniscal tear samples and controls. In the analysis involving only controls, GAPDH+18S was the most frequently identified pair. In the analysis of only isolated meniscal tear samples and in the analysis of meniscal tear samples of patients with concomitant ACL tears and controls, both HPRT1+TBP and HPRT1+GAPDH were identified as suitable pairs. If the gene expression study aims to compare non-injured meniscus, isolated meniscal tears and meniscal tears of patients with ACL tears as three independent groups, the trio of HPRT1+TBP+GAPDH is the most suitable combination of reference genes.
authors.affiliation: Departamento de Ortopedia e Traumatologia, Universidade Federal de São Paulo, 04038-032, São Paulo, SP, Brazil; Disciplina de Genética, Departamento de Morfologia e Genética, Universidade Federal de São Paulo, 04023-001, São Paulo, SP, Brazil. Electronic address: mariana.morf@epm.br.
authors.forename: Mariana Ferreira
authors.initials: MF
authors.lastname: Leal
authors.affiliation: Departamento de Ortopedia e Traumatologia, Universidade Federal de São Paulo, 04038-032, São Paulo, SP, Brazil.
authors.forename: Gustavo Gonçalves
authors.initials: GG
authors.lastname: Arliani
authors.affiliation: Departamento de Ortopedia e Traumatologia, Universidade Federal de São Paulo, 04038-032, São Paulo, SP, Brazil.
authors.forename: Diego Costa
authors.initials: DC
authors.lastname: Astur
authors.affiliation: Departamento de Ortopedia e Traumatologia, Universidade Federal de São Paulo, 04038-032, São Paulo, SP, Brazil.
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Franciozi
authors.affiliation: Departamento de Ortopedia e Traumatologia, Universidade Federal de São Paulo, 04038-032, São Paulo, SP, Brazil.
authors.forename: Pedro
authors.initials: P
authors.lastname: Debieux
authors.affiliation: Departamento de Ortopedia e Traumatologia, Universidade Federal de São Paulo, 04038-032, São Paulo, SP, Brazil.
authors.forename: Carlos Vicente
authors.initials: CV
authors.lastname: Andreoli
authors.affiliation: Disciplina de Genética, Departamento de Morfologia e Genética, Universidade Federal de São Paulo, 04023-001, São Paulo, SP, Brazil.
authors.forename: Marília Cardoso
authors.initials: MC
authors.lastname: Smith
authors.affiliation: Departamento de Ortopedia e Traumatologia, Universidade Federal de São Paulo, 04038-032, São Paulo, SP, Brazil.
authors.forename: Alberto de Castro
authors.initials: AC
authors.lastname: Pochini
authors.affiliation: Departamento de Ortopedia e Traumatologia, Universidade Federal de São Paulo, 04038-032, São Paulo, SP, Brazil.
authors.forename: Benno
authors.initials: B
authors.lastname: Ejnisman
authors.affiliation: Departamento de Ortopedia e Traumatologia, Universidade Federal de São Paulo, 04038-032, São Paulo, SP, Brazil.
authors.forename: Moises
authors.initials: M
authors.lastname: Cohen
mesh_terms: D000328:Adult; D005260:Female; D015870:Gene Expression; D006801:Humans; D008297:Male; D008592:Menisci, Tibial / Q000378:metabolism; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D000070600:Tibial Meniscus Injuries
keywords: Expression normalization; Gene expression; Knee injury; Meniscal tears; Reference genes; Reverse-transcription quantitative polymerase chain reaction