ABSTRACT
BACKGROUND: Hyperthermia upregulates DNAJA4, a member of heat shock proteins (HSPs) 40 family, in human keratinocytes and HPV-infected tissue. DNAJA4 deficiency enhances growth arrest induced by hyperthermia. Clusterin (CLU) and phosphorylated ERK (p-ERK) play a role in regulating cell proliferation and apoptosis, under environmental stress. OBJECTIVES: To examine the downstream molecules and signalling pathways of DNAJA4 and assess their roles in cell cycle and apoptosis of keratinocytes in response to hyperthermia. METHODS: Wild-type and DNAJA4-knockout (KO) HaCaT cells were exposed to either 44 °C (hyperthermia) or 37 °C (control) for 30 min. The expression levels of CLU and p-ERK were determined by RT-PCR and Western blotting. RNAi and PD98059 were used to inhibit the expression of CLU and p-ERK, respectively. Cell viability, cell cycle and apoptosis were analysed by MTS assay and flow cytometry. Fresh biopsy samples of human normal foreskin or condyloma acuminatum (CA) were utilized to examine the expression of CLU and p-ERK after ex vivo culture at 44 °C. RESULTS: The expression of CLU and p-ERK was significantly increased by hyperthermia treatment at 44 °C in HaCaT cells, foreskin and HPV-infected tissues. In HaCaT cells subjected to hyperthermia, DNAJA4 deficiency further augmented the expression of CLU and p-ERK. CLU deficiency enhanced the p-ERK expression. Hyperthermia-induced CLU and p-ERK exerted protective roles mainly through inhibiting apoptosis and maintaining cell cycle, respectively. CONCLUSIONS: In keratinocytes, CLU and p-ERK are induced by hyperthermia, an effect which can be further enhanced by DNAJA4 deficiency. CLU deficiency also increases p-ERK expression. Both CLU and p-ERK are critical protective factors of human keratinocytes from hyperthermia-induced injury.
Subject(s)
Clusterin , Hyperthermia, Induced , Apoptosis , Clusterin/genetics , HSP40 Heat-Shock Proteins , Humans , Hyperthermia , Keratinocytes , Protective FactorsSubject(s)
Hyperthermia, Induced/methods , Molluscum Contagiosum/therapy , Adolescent , Adult , Child , Child, Preschool , Female , Humans , Male , Pilot Projects , Treatment Outcome , Young AdultSubject(s)
DNA/genetics , Exome Sequencing/methods , Fatty Acid Transport Proteins/genetics , Melkersson-Rosenthal Syndrome/genetics , Mutation , Biopsy , DNA Mutational Analysis , Exome , Fatty Acid Transport Proteins/metabolism , Female , Humans , Male , Melkersson-Rosenthal Syndrome/diagnosis , PedigreeABSTRACT
Langerhans cells (LCs) are bone marrow-derived immature skin-residential dendritic cells (DCs) with a life cycle distinct from that of other types of DCs. The mechanisms involved in LC homeostasis and immunological functions are still not clear. MicroRNAs (miRNAs) are a class of short noncoding RNAs that regulate gene expression through either translational repression or mRNA degradation. A recent study showed that specific deletion of total miRNAs in DCs affects the homeostasis and function of only LCs, but not of other types of DCs. The roles of specific individual miRNA in LC development are still lacking. The miRNA miR-17-92 class, encoding miR-17, miR-18, miR-19a, miR-19b, miR-20 and miR-92, plays a very important role in B- and T-cell development and function. Here, we first report that epidermal LCs highly express the miR-17-92 class compared with spleen naive T cells. To further characterize the role of miR-17-92 in LC development, we generated LC-specific miR-17-92 knockout and knock-in mice. Interestingly, LC-specific gain- and loss-of-function of miR-17-92 cluster did not significantly change LC homeostasis, maturation ability, antigen capture and migration to draining lymph nodes. Thus, the miR-17-92 cluster may be functionally redundant and not critically required for LC development and function.
