title: Unfolding protein response signaling is involved in development, maintenance, and regression of the corpus luteum during the bovine estrous cycle.
abstract: The corpus luteum (CL) is a transient endocrine organ. Development, maintenance, and regression of CL are effectively controlled by dynamic changes in gene expression. However, it is unknown what types of gene are affected during the CL life span of the estrous cycle in bovine. Here, we determined whether unfolded protein response (UPR) signaling via eIF2α/ATF4/GADD34, p90ATF6/p50ATF6, and IRE1/XBP1, which is a cellular stress response associated with the endoplasmic reticulum (ER), is involved in the bovine CL life span. Our results indicated that expression of Grp78/Bip, the master UPR regulator, was increased during the maintenance stage and rapidly decreased at the regression stage. Additionally, UPR signaling pathways genes were found to be involved in luteal phase progression during the estrous cycle. Our findings suggested that Grp78/Bip, ATF6, and XBP1 act as ER chaperones for initiating CL development and maintaining the CL. In addition, we investigated whether ER stress-mediated apoptosis is occurred through three UPR signaling pathways in CL regression stage. Interestingly, pIRE1 and CHOP were found to be involved in both the adaptive response and ER stress-mediated apoptosis. During the CL regression stage, increased expression of pJNK and CHOP, two components of ER stress-mediated apoptotic cascades, occurred before increased level of cleaved caspase 3 were observed. The present investigation was performed to identify a functional link between UPR signaling and CL life span during the bovine estrous cycle. Taken together, results from this study demonstrated that UPR protein/gene expression levels were different at various stages of the bovine CL life span. Variations in the expression of these protein/genes may play important roles in luteal stage progression during the estrous cycle.
authors.affiliation: School of Life Science and Biotechnology (BK 21 plus program), Kyungpook National University, Daegu 702-701, Republic of Korea.
authors.forename: Hyo-Jin
authors.initials: HJ
authors.lastname: Park
authors.forename: Sun-Ji
authors.initials: SJ
authors.lastname: Park
authors.forename: Deog-Bon
authors.initials: DB
authors.lastname: Koo
authors.forename: Il-Keun
authors.initials: IK
authors.lastname: Kong
authors.forename: Min Kyu
authors.initials: MK
authors.lastname: Kim
authors.forename: Jin-Man
authors.initials: JM
authors.lastname: Kim
authors.forename: Myung-Sook
authors.initials: MS
authors.lastname: Choi
authors.forename: Young-Ho
authors.initials: YH
authors.lastname: Park
authors.forename: Sun-Uk
authors.initials: SU
authors.lastname: Kim
authors.forename: Kyu-Tae
authors.initials: KT
authors.lastname: Chang
authors.forename: Choon-Keun
authors.initials: CK
authors.lastname: Park
authors.forename: Jung-Il
authors.initials: JI
authors.lastname: Chae
authors.forename: Dong-Seok
authors.initials: DS
authors.lastname: Lee
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics; D051702:Activating Transcription Factor 6 / Q000378:metabolism; D000818:Animals; D002417:Cattle; D003338:Corpus Luteum / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D004268:DNA-Binding Proteins / Q000378:metabolism; D000091342:Endoplasmic Reticulum Chaperone BiP; D060746:Endoplasmic Reticulum-Associated Degradation; D030762:Estrous Cycle / Q000235:genetics / Q000378:metabolism*; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006360:Heat-Shock Proteins / Q000378:metabolism; D003341:Luteolysis / Q000235:genetics / Q000378:metabolism*; D058767:Protein Unfolding; D000071701:Regulatory Factor X Transcription Factors; D015398:Signal Transduction; D014157:Transcription Factors / Q000378:metabolism; D056811:Unfolded Protein Response
chemical_list: D051702:Activating Transcription Factor 6; D004268:DNA-Binding Proteins; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors; D015096:3-Hydroxysteroid Dehydrogenases
keywords: Corpus luteum; ER stress; Estrous cycle; Progesterone; Steroidogenic enzymes; Unfolding protein response