title: Testosterone production by a Leydig tumor cell line is suppressed by hyperthermia-induced endoplasmic reticulum stress in mice.
abstract: OBJECTIVE
  Leydig cells are characterized by their ability to produce testosterone. When the Leydig cells are unable to produce enough testosterone, spermatogenesis fails completely. Considering this, it is of great interest to investigate whether the expressions of steroidogenic enzymes are affected by testicular heat stress. This study aimed to demonstrate that heat induced ER-stress significantly influences steroidogenic enzyme expression and testosterone production in the Leydig cells.
  
  
  METHODS
  C57BL/6 mice were subjected to repetitive testicular heat-treatment at 42 °C for 15 min per day, and heat-treated mLTC-1 cells following hCG treatment for 1h. The protein and RNA expressions were measured by Western blot, RT-PCR. The testosterone and progesterone levels were detected by EIA. The histological and pathological characteristics using hematoxylin and eosin (H&E) and antibody stains.
  
  
  RESULTS
  The 3β-HSD expression was decreased by heat-stress and hCG treatment. While the GRP78/BiP and CHOP levels were increased by ER-stress inducers, those of the steroidogenic enzyme and progesterone were decreased. In contrast, an ER-stress inhibitor rescued the testosterone levels, even under heat-stress conditions. Moreover, the Leydig cells were randomly scattered, and severely damaged upon repetitive testicular heat-treatment. Additionally, immunohistochemical analyses revealed that cleaved caspase-3 was elevated in the testicular Leydig cells, and rescued by TUDCA. Thus, repetitive testicular heat-treatment in mice promotes excessive ER-stress, thereby leading to apoptosis of the Leydig cells and thus, decreased testosterone production.
  
  
  CONCLUSIONS
  Our findings help to provide an ER-stress mediate mechanistic explanation to the impairment of spermatogenesis upon elevation of the testicular temperature.
authors.affiliation: School of Life Sciences and Biotechnology, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea.
authors.forename: Jung-Hak
authors.initials: JH
authors.lastname: Kim
authors.affiliation: School of Life Sciences and Biotechnology, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea.
authors.forename: Sun-Ji
authors.initials: SJ
authors.lastname: Park
authors.affiliation: Embryology Laboratory, Neway Fertility, 115 East 57th Street Suite 500, New York, NY 10022, USA.
authors.forename: Tae-Shin
authors.initials: TS
authors.lastname: Kim
authors.affiliation: Cancer Research Institute and Department of Pathology, School of Medicine, Chungnam National University, Daejeon 305-732, Republic of Korea.
authors.forename: Jin-Man
authors.initials: JM
authors.lastname: Kim
authors.affiliation: School of Life Sciences and Biotechnology, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Republic of Korea. Electronic address: Lee1@knu.ac.kr.
authors.forename: Dong-Seok
authors.initials: DS
authors.lastname: Lee
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D045744:Cell Line, Tumor; D006063:Chorionic Gonadotropin / Q000494:pharmacology; D000091342:Endoplasmic Reticulum Chaperone BiP; D059865:Endoplasmic Reticulum Stress; D006360:Heat-Shock Proteins / Q000096:biosynthesis; D006358:Hot Temperature; D006979:Hyperthermia, Induced; D007984:Leydig Cell Tumor / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011374:Progesterone / Q000096:biosynthesis; D012313:RNA / Q000096:biosynthesis; D013256:Steroids / Q000096:biosynthesis; D013739:Testosterone / Q000096:biosynthesis*; D051742:Transcription Factor CHOP / Q000096:biosynthesis
chemical_list: D006063:Chorionic Gonadotropin; C497250:Ddit3 protein, mouse; D000091342:Endoplasmic Reticulum Chaperone BiP; D006360:Heat-Shock Proteins; C000717248:Hspa5 protein, mouse; D013256:Steroids; D051742:Transcription Factor CHOP; D013739:Testosterone; D011374:Progesterone; D012313:RNA; D015096:3-Hydroxysteroid Dehydrogenases; C505409:Casp3 protein, mouse; D053148:Caspase 3
keywords: Apoptosis; Endoplasmic reticulum stress; Heat stress; Leydig cells; Testosterone