Expression of translationally controlled tumor protein in heat-stressed human dental pulp cells.
OBJECTIVE
The aim of this study was to investigate the effects of heat stress on cell viability, translationally controlled tumor protein (TCTP) expression, and the effects of recombinant TCTP on heat-stressed human dental pulp cells (HDPCs).


METHODS
HDPCs were isolated from human teeth and cultured at 37°C. For heat stress, HPDCs were incubated at 43°C for 45min. After heat stress, recombinant TCTP were added to HDPCs and cultured for various periods of time at 37°C. Heat-treated cells were then analyzed by DNA staining with Hoechst 33258, MTT, and caspase 3 activity assays. TCTP expression level was assessed by real-time PCR and western blot analysis.


RESULTS
Heat-treated cells displayed lower cell density and nuclear morphology resembling apoptotic body. Heat stress significantly decreased cell viability and induced activity of caspase 3. The effect of recombinant TCTP on pulp cell death from heat stress varied depending on each subject and TCTP concentration. Heat stress up-regulated TCTP mRNA expression level. In contrast, TCTP protein level remained unchanged. Recombinant TCTP did not affect TCTP mRNA expression but down-regulated TCTP protein in heat-treated cells.


CONCLUSIONS
Heat stress induces caspase 3 activation and up-regulates TCTP mRNA expression in HDPCs. TCTP did not play a key role on pulp cell recovery from heat stress.
Department of Molecular Biotechnology and Bioinformatics, Faculty of Science, Prince of Songkla University, Songkhla, Thailand.
Canussanun
C
Jirachotikoon
Department of Oral Biology and Occlusion, Faculty of Dentistry, Prince of Songkla University, Songkhla, Thailand. Electronic address: sissada.t@psu.ac.th.
Sissada
S
Tannukit
Department of Oral Biology and Occlusion, Faculty of Dentistry, Prince of Songkla University, Songkhla, Thailand.
Ureporn
U
Kedjarune-Leggat
D000293:Adolescent; D000328:Adult; D000818:Animals; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D053148:Caspase 3 / Q000378:metabolism; D016923:Cell Death; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D015536:Down-Regulation; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D006358:Hot Temperature; D006801:Humans; D033561:Penaeidae; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D000090324:Tumor Protein, Translationally-Controlled 1; D015854:Up-Regulation; D055815:Young Adult
D014408:Biomarkers, Tumor; D012333:RNA, Messenger; D011994:Recombinant Proteins; C000715647:TPT1 protein, human; D000090324:Tumor Protein, Translationally-Controlled 1; D053148:Caspase 3
Apoptosis; Dental pulp; Heat stress; TCTP